Michael P. Nageotte, MD

• Executive Careline Director
• Long Beach Memorial Hospital
• Long Beach, California
• Professor, Department of Obstetrics and Gynecology
• University of California at Irvine
• Irvine, California

Music training related to brain changes has been shown to alter cortical circuitry and connections that underlie sound processing (Patel treatment uveitis order 2 mg ropinirole otc, 2003) symptoms 10dpo 0.5 mg ropinirole purchase with mastercard. Training in instrumental music powerfully engages a large number of sensorimotor and higher-order cognitive processes because of the numerous and interacting skills required to attain proficiency (Kraus medicine 911 0.5 mg ropinirole buy mastercard, 2012; Moreno & Bidelman symptoms ketoacidosis order ropinirole online pills, 2014) treatment alternatives boca raton ropinirole 0.5 mg buy cheap. More critically, musical abilities of an individual have been shown to be related to gains in linguistic capacity, both receptively and expressively (Weiss & Bidelman, 2015). Given the strong modulatory influences of the brainstem on cortical areas for a wide range of perceptual and cognitive behaviors, does musical training translate into brainstem-level changes as well In a recent study by Weiss and Bidelman (2015), brainstem responses to decisions about speech intelligibility were found to be superior in trained musicians compared to untrained nonmusicians. The authors hypothesized that musical experiences may have caused enhanced neuroplastic changes to brainstem circuitry that participates in early auditory signal processing. These subcortical enhancements may have contributed to the faster and better decisions that musically trained individuals in their study made on factors related to speech perception. It is thought that trained musicians may have a more reliable and accurate representation of the general acoustic features of sound - features that are first processed in the brainstem. These improved and enriched brainstemlevel sound recognition abilities may be the same ones used to better identify speech sounds near categorical boundaries, thus making speech more comprehensible. In other words, musical training appears to enhance or "tune" the early stages of complex auditory processing of sounds in the brainstem, an effect referred to as pre-attentive sensory learning (Weiss & Bidelman, 2015). This study, and others like it, squarely argue for the importance and benefits of early musical training for positively influencing the reliability with which speech-related acoustic features are appreciated by the brain. Examining neural plasticity and cognitive benefit through the unique lens of musical training. Listening to the brainstem: Musicianship enhances intelligibility of subcortical representations for speech. Stylopharyngeus elevates and widens the rostral area of the pharynx and operates to shorten the pharyngeal passageway during the swallow. This action may also contribute to the cross-section volume changes necessary to alter the first and second formants of vowels. Afferent fibers from baroreceptors project to the caudal region of the solitary nucleus in the medulla. The dorsal motor nucleus of vagus is considered the chief parasympathetic nucleus of the brain, indicating that its actions are related to returning the body to equilibrium after a period of excitation. The interconnection between the solitary and dorsal motor nuclei allows for blood pressure measures within the vasculature in and around the heart to influence cardiac rate. This response is commonly referred to as the baroreceptor reflex (Kiernan, 2005; McMullan & Pilowsky, 2010). Inputs from these sensory endings cHaPter 4 Neuroanatomy: anatomical Nomenclature, embryology, the spinal cord, and the Brainstem 147 enter the brainstem and synapse onto neurons of the caudal solitary nucleus. Within the reticular formation are descending pathways, known as reticulospinal fibers, which innervate motoneurons of the cervical spinal cord. The importance of all this connectivity is that the upper cervical spinal cord drives contraction of the diaphragm. Thus, changes in blood chemistry operate to increase respiration rate and depth to normalize these blood chemistry measures. In Latin, the term vagus is translated to "wandering," as in the English word vagabond. The vagus exits the brainstem on the ventrolateral aspect of the medulla, just behind the pyramids, in the form of a large plexus or bundle of fibers (Siegel & Sapru, 2006; Wilson-Pauwels et al. These fibers contain axons from each of the five functional components making up this cranial nerve system. As these fibers exit the brainstem, they divide into several key branches that project to the musculature of the pharynx and larynx. You should also be aware as a speech pathologist that clients who have undergone some form of surgery in the neck region, such as cervical vertebral fusion, often present with swallowing deficits and vocal fold paralysis. These autonomic fibers innervate several visceral body structures, including the respiratory system and the gastrointestinal tract, as well as the spleen, liver, and kidneys. Fibers from these regions project centrally to the brainstem and synapse onto neurons of the solitary nucleus in the dorsal medulla. The principal function of these sensory inputs is to drive the production of visceral reflexes, such as peristalsis, vomiting, coughing, gagging, production of phlegm in various segments of the respiratory system, and the reflexive control of blood pressure. Connections from the solitary nucleus to the dorsal motor nucleus of vagus underlie the expression of these visceral responses. As with all other taste-related inputs, these signals project to the gustatory center of the rostral solitary nucleus. Tactile and proprioceptive inputs from the laryngeal region are hypothesized to be a key source of afferent information during the voluntary motor control of the vocal folds during vocalization (Ludlow, 2004). For humans, the need for robust amounts of detailed afferent information during vocalization is likely very high given the exquisite degree of control we have over adjustments in the position and stiffness of vocal fold tissues (affecting vocal pitch). Animal studies in a variety of different species have confirmed that the internal surface of the larynx is richly supplied with tactile sensory receptors that can encode changes to the shape of the vocal folds as well as tell us how they are moving (Andreatta, Mann, Poletto, & Ludlow, 2002). A limited number of neuroanatomical studies have demonstrated that afferent inputs originating from the larynx can activate neurons of the periaqueductal gray region in the cat, an area known to be related to vocalization control (Ambalavanar, Tanaka, Damirjian, & Ludlow, 1999). Unfortunately, in humans, the exact pathway of laryngeal sensory inputs from the periphery to the brain continues to be poorly understood. Velopharyngeal movement can be assessed by observing the palate moving up and down during repeated production of the syllable /ah/. Deviation of the uvula or asymmetrical palatal motion is a sure sign of paralysis caused by vagal damage. The uvula will deviate away from the damaged side because tonic muscle activity on the healthy side is unopposed, pulling the uvula in that direction. The integrity of the laryngeal motor system can be grossly assessed by listening to the person speaking and noting for hoarseness, pitch breaks, or breathy vocal quality. Any of these conditions can be the result of some degree of vocal fold paralysis or other pathologies. Although direct visual imaging of the larynx is the optimal way to clinically assess vocal fold motion, in the absence of endoscopic equipment, perceptual testing is sufficient to gain a gross overview of a deficit affecting voice. The gag reflex is elicited by lightly stroking the anterior faucial pillars with a tongue depressor. The sternocleidomastoid produces head rotation and flexion of the neck, whereas the trapezius operates to retract and depress the shoulder region. Some anatomists have suggested that the medullary segment of the accessory nucleus (the segment that is actually in the brainstem) is an extension of the nucleus ambiguus due to the embryonic similarities among the cells. This view is consistent with the position of the accessory nucleus relative to the nucleus ambiguus. Lesions to the accessory nerve produce a drooping of the shoulder ipsilateral to the injury and impaired head turning and neck flexion to the contralateral side when a resistance is applied (patient tries turning head or flexing neck while the clinician pushes gently in the opposite direction). First, if the person is supine, ask the patient to lift his or her head off the pillow, or if the person is upright request that he or she turn his or her head to the contralateral side against a resistance. Trapezius assessment is straightforward and a matter of observing the symmetry between the left and right shoulders. To confirm damage, you could also ask the patient to elevate his or her shoulders as you apply a downward resistive force. While intrinsic tongue muscles operate to produce nuanced shape change to the tongue body, extrinsic muscles set the overall position of the tongue in the oral cavity during speech and feeding actions. Together, precision control of the tongue is a leading factor in speech intelligibility. The tongue, when at rest, will have a pronounced curvature toward the affected side because of the lack of mechanical opposition relative to the healthy side. The surface of the affected side also will appear much more wrinkled, less bulky, and atrophied upon palpation. Such a situation will lead to a significant flaccid dysarthria and swallowing difficulties during the oral and pharyngeal phases. Because the tongue now lacks fine mobility, speech intelligibility will be affected to a degree related to the severity of the motor control deficit. This method will reveal finer degrees of impairment than gross motor tongue protrusion and lateralization tasks typically performed during an oral mechanism exam. Learning the relationship between neuroanatomic structures requires you to create a "geographical" and "functional" map in your mind. Understanding the workings of the nervous system is directly related to your ability to appreciate the physical relationships and functional interactions among numerous anatomical structures that underlie a given behavior. Development of the nervous system begins with the process of neurulation, whereby the ectoderm of the early embryo differentiates into the neural tube and neural crest cells. Structural and organizing features of various segments of the nervous system can be traced back directly to embryological development. The spinal cord acts as the chief input and output site for sensory and motor signals between the body and the nervous system. First, the spinal cord receives all manner of sensory inputs from sensory endings located in the skin, muscle tissue, connective tissues, and viscera. These inputs are critical for providing realtime feedback of internal and external environmental conditions that inform and guide actions taken by the nervous system. Second, the spinal cord is responsible for the transmission of ascending and descending information via segregated fiber tracts that interconnect the periphery with the cerebral cortex, brainstem, and gray matter within the spinal cord itself. Through these pathways, the brain is able to act upon and perceive the world around us. Each major component of the brainstem (midbrain, pons, and medulla) possesses characteristic structural features and functions that allow for the localization of normal and disordered behavior to specific subareas. Behaviors such as speech, hearing, swallowing, facial gesturing, and voice production depend heavily upon the health and integrity of these nuclei and their associated cranial nerves. The medulla is a critical center for cranial nerve function associated with sensory and motor behaviors related to hearing and balance, swallowing, voice production, and motion of the tongue. In addition, the medulla houses other nuclei such as the inferior olive, the cuneate, and gracile nuclei, which are all involved in the transmission of sensory information from the body below the neck to cerebellar and/or primary sensorimotor processing areas in the cerebrum. Lastly, the medulla plays a crucial and life-sustaining role in cardiovascular and respiratory function through the existence of clusters of interconnected cells within the reticular formation of the medullary brainstem. The pons operates as a key anatomical bridge between the cerebrum, spinal cord, and cerebellum. Connections among the frontal cerebrum, spinal cord, and cerebellum are crucial during the learning of new skills and the refinement of coordinated movements. The pons is a critical center for cranial nerve motor functions related to control of the facial muscles, mandible, and motion of the eye. Nuclei within the pontine tegmentum mediate tactile and movement-related sensory inputs from the skin of the face, oral mucosa, and the mandibular region. The pons also houses several noncranial nerve system nuclei related to sound localization, attention, and respiratory control. The mesencephalon (midbrain) is the uppermost segment of the brainstem and is a major conduit for both ascending and descending axon pathways. Additionally, it is a critical center for cranial nerve functions associated with motion of the eyes and visual 152 Neuroscience Fundamentals for communication sciences and disorders sectioN 1 the top ten list continued reflexes to light. The midbrain also houses nuclei that are closely associated with motor control functions of the cerebellum and basal ganglia, and with sound and visual signal processing. The cranial nerves consist of 12 pairs of nerves that emerge from the brainstem and the ventral surface of the cerebrum. Cell bodies of cranial nerves mediating motor and sensory functions are located within various brainstem nuclei. Cranial nerve nuclei are classified into different functional groupings reflecting three interacting categories: (a) the quality of the information carried by the nerves and processed by the associated nuclei, (b) the site of innervation, and (c) the distribution pattern of the nerve. For speech pathologists and audiologists, understanding and being able to describe the normal and disordered functioning of cranial nerve systems is critically important. Because speech production, facial gesturing, hearing, and swallowing behaviors are all reliant on the health and integrity of the cranial nerves, the diagnostic and therapeutic information that one can obtain from appreciating these complex systems is substantial. Explain the nature of the ventral and dorsal roots in relation to the spinal nerve. For each fasciculus, identify the afferent and efferent fiber tracts and pathways contained within. Identify, label, and describe the major subdivisions and external structural landmarks for all areas of the brainstem. Create a summary table that lists the unique functional and structural characteristics of each brainstem subdivision. What functional and structural elements are shared across two or more brainstem subdivisions How does the medullary reticular formation contribute to cardiac function and respiration Laryngeal afferent stimulation enhances fos immunoreactivity in periaqueductal gray in the cat. Brainstem reflexes: Electrodiagnostic techniques, physiology, normative data, and clinical applications. Recent advances in laryngeal sensorimotor control for voice, speech and swallowing. Central nervous system control of interactions between vocalization and respiration in mammals. Brainstem circuits that control mastication: Do they have anything to say during speech Visual accommodation in vertebrates: Mechanisms, physiological response and stimuli. Perioral somesthetic sensibility: Do the skin of the lower face and the midface exhibit comparable sensitivity Brainstem projections to the major respiratory neuron populations in the medulla of the cat.

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Toxic shock syndrome toxin is a superantigen that stimulates the release of large amounts of cytokines from many helper T cells medications 1 discount ropinirole 1 mg buy. Diagnosis: Tinea corporis (ringworm) caused by one of the dermatophytes medications japan best ropinirole 0.25 mg, especially species of Microsporum medicine glossary buy ropinirole, Trichophyton medicine research discount ropinirole 2 mg free shipping, or Epidermophyton medicine lyrics generic ropinirole 0.25 mg visa. Dermatophytes use keratin as a nutrient source, so lesions are limited to the skin. Vaginal examination reveals two flat, moist, slightly raised lesions on the labia. Material from a labial lesion examined in a dark-field microscope revealed spirochetes. The rash on the palms coupled with the vaginal lesions (condylomata lata) is compatible with secondary syphilis. On examination, she has a temperature of 39°C, the right external canal contained dried blood, the drum was perforated, and a small amount of purulent fluid was seen. These organisms colonize the oropharynx and enter the middle ear via the eustachian tube. The lesions are scattered over the body, are irregularly shaped, and are not raised. Today, she also complains of headache and abdominal pain but no nausea, vomiting, or diarrhea. Travel history reveals she returned from an extended trip to several countries in central Africa 1 week ago. If banana-shaped gametocytes seen in the blood smear, think Plasmodium falciparum. Plasmodium falciparum is the species that causes the life-threatening complications of malaria, such as cerebral malaria. The fever and chills experienced by the patient coincide with the release of merozoites from infected red blood cells and occur in either a tertian or quartan pattern. Analysis of his spinal fluid reveals no abnormality, and no organisms are seen in the Gram stain. Pathologic examination of the brain reveals eosinophilic inclusion bodies in the cytoplasm of neurons. The patient was a farm worker who was bitten by a bat about a month prior to the onset of symptoms. People bitten by a bat (or any wild animal) should receive rabies immunization consisting of the inactivated vaccine plus rabies immune globulins (passive­active immunization). Three days later, he spiked a fever, and there was pus on the dressing that had a blue­green color. On examination, she is afebrile but has a staggering gait, and myoclonus can be elicited. On autopsy, microscopic examination of the brain reveals many vacuoles but no viral inclusion bodies. Urinalysis shows many red cells, no white cells, and several large eggs with terminal spines. Schistosome eggs in venules of the bladder damage the bladder epithelium and cause bleeding. When questioned, he says that cheeses, especially the unpasteurized varieties, are some of his favorite foods. Domestic animals such as cows and goats are the main reservoir for Brucella, and it is often transmitted in unpasteurized dairy products. A few days prior to the appearance of the rash, she had a runny nose and anorexia. This virus also causes aplastic anemia because it preferentially infects and kills erythroblasts. It also infects the fetus, causing hydrops fetalis, and causes an immune complex­ mediated arthritis, especially in adult women. Forty-eight hours later, he spiked a fever (temperature, 40°C), and the wound area became necrotic. Crepitus was felt, and a foul-smelling odor was perceived originating from the wound. The main virulence factor produced by this organism is an exotoxin that is a lecithinase. It causes necrosis of tissue and lysis of red blood cells (causing hemolytic anemia). A foul-smelling exudate is characteristic of infections caused by anaerobic bacteria. Sexual history reveals she is a commercial sex worker and has had unprotected vaginal, oral, and anal intercourse with multiple partners. The absence of vesicles indicates that her symptoms are not caused by herpes simplex virus type 2. There are three genera of curved gram-negative rods: Vibrio, Campylobacter, and Helicobacter. If an outbreak of bloody diarrhea had occurred in the refugee camp, then Shigella dysenteriae would be the most likely cause. Pertinent past history includes rheumatic fever when he was 15 years old and the extraction of two wisdom teeth about 3 weeks before his symptoms began. Blood cultures grow gram-positive cocci in chains that produce green (alpha) hemolysis on blood agar. Diagnosis: Subacute bacterial endocarditis caused by one of the viridans group streptococci, such as Streptococcus sanguinis. The laboratory findings are also compatible with Enterococcus faecalis, but the history of dental surgery makes the viridans group streptococci more likely to be the cause. Pertinent past history includes her cigarette smoking (2 packs per day for 40 years) and her occupation as an archaeologist, digging primarily in Arizona and New Mexico. Pathologic examination revealed large (25 m) round structures with thick walls and many round spores inside. Detection of IgM antibody in the Sabin-Feldman dye test can also be used to make a diagnosis. Domestic farm animals, such as cattle, acquire the organism by accidentally eating cat feces. A Giemsa-stained smear of material from the base of a vesicle revealed multinucleated giant cells with intranuclear inclusions. Life-threatening encephalitis and disseminated infection of the neonate also occur. There is a history of headaches for the past week and one episode of vertigo but no previous seizures. She is a native of Honduras but has lived in the United States for the past 5 years. Infection is acquired by ingesting the tapeworm eggs, not by ingesting undercooked pork. This clinical picture can also be caused by a brain abscess, a granuloma such as a tuberculoma, or a brain tumor. The inclusion contains large numbers of the intracellular replicating forms called reticulate bodies. In order to do this, the student should know the reservoir of the organism, its mode of transmission, and the meaning of factors such as travel, occupation, and exposure to pets, farm animals, or wild animals. Knowledge of the microbes that typically cause disease in individuals with specific immunodeficiencies will also be helpful. Toxoplasma gondii Disease Enterocolitis and hemolytic-uremic syndrome Enterocolitis Variant Creutzfeldt-Jakob disease Taeniasis (intestinal tapeworm) Toxoplasmosis Neonatal sepsis Brucellosis Intestinal tuberculosis Anthrax Q fever Brucellosis Taeniasis (intestinal tapeworm) Trichinosis Enterocolitis Enterocolitis Echinococcosis Visceral larva migrans Leptospirosis Rabies Sepsis Tinea corporis Toxoplasmosis Cellulitis Cat-scratch disease; bacillary angiomatosis Rabies 3 2. Contact with animal hides Sheep Goats Pigs Poultry (chickens; turkeys) Dogs Inhalation of amniotic fluid Ingestion of milk products Ingestion of meat1 Ingestion of meat or eggs1 1. Ingestion of eggs in human feces, not ingestion of pork, results in cysticercosis. Sparrows Snakes, turtles Beaver Fish Inhale aerosol Inhale aerosol Inhale aerosol Inhale spores Mosquito bite Fecal­oral Fecal­oral Ingestion of fish1 Chlamydia psittaci Influenza virus Cryptococcus neoformans Histoplasma capsulatum Encephalitis viruses. Mycobacterium fortuitum-chelonei Pseudomonas aeruginosa, Acinetobacter baumannii P. Bacteria Treponema pallidum Neisseria gonorrhoeae Chlamydia trachomatis Streptococcus agalactiae (group B Streptococcus) Escherichia coli Listeria monocytogenes C. Papule is a raised, erythematous lesion with no visible fluid inside; resembles a mosquito bite. Vesicle is a raised, erythematous lesion with yellowish fluid (resembling plasma) inside; approximately the same size as a papule. Pustule is a raised, erythematous lesion with cloudy fluid (pus) inside; typically larger than a papule or vesicle. During an outbreak of gastrointestinal disease caused by an Escherichia coli strain sensitive to ampicillin, tetracycline, and chloramphenicol, a stool sample from one patient yields E. A retrovirus without an oncogene does not induce leukemia in mice; after repeated passages through mice, viruses recovered from a tumor were highly oncogenic and contained a new gene. Questions 47­51 (A) Diphtheria toxin (B) Tetanus toxin (C) Botulinum toxin (D) Toxic shock syndrome toxin (E) Cholera toxin 47. An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery. Your patient is a 30-year-old woman with nonbloody diarrhea for the past 14 hours. A 50-year-old homeless alcoholic has a fever and is coughing up 1 cup of green, foul-smelling sputum per day. Your patient has subacute bacterial endocarditis caused by a member of the viridans group of streptococci. A culture of skin lesions from a patient with pyoderma (impetigo) shows numerous colonies surrounded by a zone of -hemolysis on a blood agar plate. The coagulase test, in which the bacteria cause plasma to clot, is used to distinguish: (A) Streptococcus pyogenes from Enterococcus faecalis (B) Streptococcus pyogenes from Staphylococcus aureus (C) Staphylococcus aureus from Staphylococcus epidermidis (D) Staphylococcus epidermidis from Neisseria meningitidis 63. For which one of the following bacterial vaccines are toxic side effects an important concern Your patient is a 70-year-old man who underwent bowel surgery for colon cancer 3 days ago. You perform a Gram stain on a specimen of the discharge and see neutrophils but no bacteria. Two hours after a delicious Thanksgiving dinner of barley soup, roast turkey, stuffing, sweet potato, green beans, cranberry sauce, and pumpkin pie topped with whipped cream, the Smith family of four experience vomiting and diarrhea. Your patient has a brain abscess that was detected 1 month after a dental extraction. Five hours after eating reheated rice at a restaurant, a 24-yearold woman and her husband both developed nausea, vomiting, and diarrhea. Which one of the following organisms principally infects vascular endothelial cells and as a result often causes a petechial rash She denies having had sexual contact with a partner who had symptoms of a venereal disease. Acute glomerulonephritis is a nonsuppurative complication that follows infection by which one of the following organisms A 70-year-old man is found to have a hard mass in his prostate, which is suspected to be a carcinoma. Twenty-four hours after surgical removal of the mass, he develops fever to 39°C and has several shaking chills. Diarrhea caused by which one of the following agents is characterized by the presence of fecal leukocytes Tissue-degrading enzymes play an important role in the pathogenesis of several bacteria. Three organisms, Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae, cause the vast majority of cases of bacterial meningitis. Which one of the following organisms causes diarrhea by producing an enterotoxin that increases adenylate cyclase activity within enterocytes Causes a pseudomembrane in the throat, which can cause respiratory tract obstruction 147. Causes meningitis in neonates and the immunosuppressed Questions 148­150 (A) Escherichia coli (B) Klebsiella pneumoniae (C) Salmonella enteritidis (D) Proteus mirabilis 148. Is frequently implicated in nosocomial infections, is an important cause of community-acquired pneumonia in adults, and has a thick, mucoid capsule 149. Pathogenicity associated primarily with urinary tract infections; produces urease Questions 151­154 (A) Staphylococcus aureus (B) Streptococcus pyogenes (C) Enterococcus faecalis (D) Streptococcus pneumoniae 151. Is associated with rheumatic fever Questions 155­158 (A) Bacteroides fragilis (B) Haemophilus influenzae (C) Pseudomonas aeruginosa (D) Chlamydia pneumoniae 155. Oxidase-positive gram-negative rod that is an important cause of wound and burn infections 157. Questions 137­140 (A) Mycobacterium avium-intracellulare (B) Treponema pallidum (C) Rickettsia prowazekii (D) Mycoplasma pneumoniae 137. Is an acid-fast rod Questions 141­143 (A) Borrelia burgdorferi (B) Helicobacter pylori (C) Pasteurella multocida (D) Brucella melitensis 141. Viruses enter cells by adsorbing to specific sites on the outer membrane of cells. A temperate bacteriophage has been induced from a new pathogenic strain of Escherichia coli that produces a toxin. A stock of virus particles has been found by electron microscopy to contain 108 particles/mL, but a plaque assay reveals only 105 plaque-forming units/mL.

The vast majority of neurons that produce this transmitter are located in a region of the brainstem called the substantia nigra (Latin for "black looking stuff ") medicine queen mary order ropinirole no prescription. Epi will cause blood vessels to dilate (increase in diameter) within skeletal muscle tissue medications covered by medicare generic 1 mg ropinirole amex, increasing blood flow and the availability of oxygen and glucose to support greater degrees of contraction medications 1 1 mg ropinirole order with amex. In the cardiac system symptoms zoloft overdose buy 0.5 mg ropinirole free shipping, Epi will cause the system to increase the rate and power of cardiac output symptoms vaginal cancer order ropinirole with a visa, rapidly raising blood pressures. Epi also increases glucose levels in the blood, providing the body with energy in times of stress when increased attention and activity are required. Neurons of the raphe nuclei are known to have widespread projections to the brain and spinal cord. Modern classes cHaPter 3 Basics of Neural signaling and synaptic Function 75 of drugs to treat these conditions, such as Zoloft or Prozac, operate on neurons expressing serotonin, specifically inhibiting (blocking) reuptake transporters in the synapse (go back to the synapse section to remind yourself of this mechanism) and allowing for serotonin to remain for a longer time in the cleft. Peptides are short chains of amino acids, or you can think of them loosely as very small proteins. A neuropeptide, then, is a peptide that resides within the nervous system and is used to communicate information between neurons (Stahl, 2013; van den Pol, 2012). Neuropeptides differ significantly from classical neurotransmitters in several ways. First, neuropeptides are generated in the soma and transported to the presynaptic terminal via fast axonal transport mechanisms. Second, in contrast to classical neurotransmitters that are released only from active zones, neuropeptides can be released from anywhere in the presynaptic terminal, suggesting that their effects go well beyond the postsynaptic region immediately opposite the terminal. Third, neuropeptides are released in small quantities and usually under conditions of intense synaptic activity. Neurons that are undergoing intense activation are ones that are the most likely to be structurally and functionally altered to enhance their behavior. Finally, neuropeptides tend to remain active for longer periods of time compared to classical transmitters. Unlike the plethora of enzymes ready and waiting to degrade classical neurotransmitters, neuropeptide inactivation is limited to simple diffusion away from the release site and/or protein degradation via extracellular proteases (an enzyme that specifically degrades proteins). Together, these differences paint a picture of a unique neurotransmitter type that is (a) metabolically more "expensive" to produce, (b) used sparingly under intense periods of synaptic activity, and (c) has widespread, long-term, and modulatory effects throughout its environment. Among the widespread and long-term effects that neuropeptides can have are (a) changes to gene expression to affect the structure and metabolism of the neuron, (b) adjustments to local blood flow affecting the availability of oxygen and glucose to active populations of neurons, and (c) modulation of pain and emotional states. Given the complexities of neuropeptide activity, drug companies and neuropharmacologists are understandably very interested in neuropeptides for their value in understanding the neural bases of these conditions, and also for fabricating treatments to combat the devastating effects of addiction on individuals. This reverse type of communication between the two sides of the synapse is referred to as retrograde messaging. Retrograde messaging is suggested to operate as a feedback system whereby the postsynaptic cell messages the presynaptic cell to alter its activity, thus modulating the "normal" form of transmission (pre- to post-). Rather, neuromodulators enhance, diminish, and/or lengthen the duration of effect of other transmitters that may have a more principal role in activating a channel. For example, ionotropic receptors can be influenced by neuromodulators through the existence of secondary binding sites on the ion channel specific to that modulator. A classic example of neuromodulation is the interaction of dopamine (well appreciated as a neuromodulator) with glutamate. In some neurons of the brain, ion channels that bind to glutamate can also bind dopamine simultaneously. When this situation arises, the normal opening response of the ion channel to glutamate alone is altered. Binding both dopamine (our neuromodulator) and glutamate simultaneously lengthens the time the ion channel remains open and conducting a current. Neuromodulators not only influence synapses directly, but also are capable of more diffuse effects. Neuromodulators can be released from any region of the presynaptic terminal, which gives them free access to diffuse over a large area. This phenomenon, known as volume transmission, has the capacity to affect large numbers of synaptic sites all at once. This can lead to a change in the bias or operating state of an entire region to more specific inputs that are coming from other sources. Over the past 20 years, though, this idea has undergone extensive revision, and we now understand that a given neuron will co-express one type of classical neurotransmitter (either an amino acid or amine) along with one or more nonclassical transmitters (neuropeptide and/or gas). Neurotransmitters are the crucial connections between neurons comprising our functionally and structurally diverse neural networks. Neurotransmission is never static, but is under continuous and dynamic adjustment to meet the moment-to-moment demands of neural networks that underlie our behavior. At this point in your study, you should have a good understanding of: · the internal and external structures comprising a neuron, along with their functionality; · the way neurons develop electrical potentials; · how a neuron develops and maintains a resting membrane potential; · how a neuron produces and propagates the action potential; · the general structure and operation of synapses; · the detailed process of synaptic transmission in chemical synapses; and · the properties and uses of neurotransmitters. If any of these bullet points are not entirely clear to you, go back through the material and the previous chapter to reread and review before moving forward. As discussed earlier, electrochemical signals represent the actual "information" that is processed by interconnected and cooperatively functioning populations of neurons to generate all forms of sensory/perceptual, motor, and cogni- tive behavior. Recalling the voting analogy that was used in Chapter 2 to highlight the operation of a single neuron in a population of neurons, we stated that the nervous system influences the performance of a behavior through the summation and combination of "votes" by individual neurons making up a given population of neurons. After all our work in this chapter, we now know that the nature of the "vote" cast by an individual neuron is the generation of an action potential and synaptic transmission. The question that we have left unanswered up until now, though, is How exactly does a neuron "decide to cast a vote" in the first place Putting this into the language of our "voting" analogy, neural integration describes how the neuron goes about "deciding" whether or not to "cast a vote" and participate in the output of the population. Neural integration is the summation of all synaptic potentials across the entire neuron. Note that excitatory synapses are localized in the dendrites, far away from the axon hillock (decision zone). On the other hand, inhibitory synapses are found on the soma or in the near vicinity of the hillock. This distribution pattern suggests that neural integration is biased, requiring far more summated excitatory input to overcome the inhibitory influence located near the decision-making zone of the neuron. To make this statement more understandable, though, we need to define exactly what we mean by the term "combine. Please note that I am purposefully avoiding any mathematical or electrical theorybased explanation of summation because what is needed from the perspective of a rehab specialist is an intuitive appreciation of this concept. Spatial summation occurs when two or more synapses are simultaneously activated, allowing for their individual postsynaptic potentials to combine to affect the overall membrane potential of the neuron. Spatial summation is the addition of multiple postsynaptic potentials arriving simultaneously from different synapses. The small trace above each colored axon terminal is the action potential activating that given synapse. The reality is that spatial and temporal summation co-occur and contribute to changing the overall electrical state of the postsynaptic neuron. The action potential created by the postsynaptic cell becomes just one of the many hundreds to thousands of presynaptic inputs that act on the next postsynaptic neuron in the chain of connections. If this were the case, the process of reaching the depolarizing threshold of the axon hillock would truly be a simple matter of linearly adding all synaptic potentials together until we had a net depolarization change of +10 mV. As such, the small size of individual synaptic potentials helps to partially explain why a neuron requires the contribution and summation of numerous synaptic potentials to accomplish the goal of triggering an action potential. Temporal summation is the addition of multiple postsynaptic potentials arriving in rapid succession in a single synapse. The reason for this dire warning is that electrical energy conducts very well through water. Without getting into the electrical theory behind this idea, electrical energy dissipates and loses strength rapidly as it moves farther away from its point of origin in a fluid medium. A good analogy for this would be how sound gets softer the farther away we are from its source. Because the intracellular environment of a neuron is mostly water, any electrical current or change in voltage will dissipate and weaken as it passively spreads father away from the point of origin. What if we examined the effects of an excitatory synapse on the soma instead, a location much closer to the axon hillock On the other hand, inhibitory synapses (red synapses) are predominately localized on the soma and in regions close to the axon hillock. To compensate for distance and decay effects, the neuron possesses thousands of excitatory synapses. The axon hillock represents the President, the entity that decides whether to execute an action or not. Inhibitory synapses closest to the axon hillock will be members of the Cabinet, while those further away on the soma will represent members of Congress. In our analogy, the issue to be debated and decided upon by our voters and government will be a growing grassroots movement to provide free public college education to everyone (a very worthy cause indeed). These parallel neural events will be those discussed from the beginning of the neural integration section. Voting analogy for neural integration: A growing grassroots movement to provide free public college education has recently gained popularity among voters to the point where Congress and the White House are starting to take notice. Input summation across the entire postsynaptic neuron is needed to adequately depolarize the cell to generate an action potential. This action potential becomes one of the many presynaptic inputs acting upon the next neuron in the network. As a group, the advisors tell the President that the idea of free college education is poor fiscal policy and that he should not sign the executive order. After being advised, the President begins to reevaluate his position and is no longer as sure of the wisdom of signing the executive order. In effect, a few key advisors have cancelled out the votes of hundreds of citizens in favor of the free college education measure. Not enough depolarization is reaching the axon hillock to cancel out the hyperpolarization by a handful of inhibitory synapses directly at the axon hillock. A new poll taken by the President now shows that 80% or 800 voters want to see the measure enacted, while only 20% oppose it. The President, upon seeing these new numbers, decides to ignore the negative views of his advisors and, with the positive support of 80% of the country, signs the executive order to make public college education free for all who want it! The summated depolarization is sufficient to compensate for any hyperpolarization being generated by the inhibitory synapses, resulting in a crossing of the firing threshold of the axon hillock. Taking into consideration (a) the small amplitude of synaptic potentials, (b) the way energy dissipates in a fluid with distance, and (c) the differences in the type of synapses (excitatory vs. A great deal of effort has been put into providing you with as intuitive (and math-free) a description of the fundamental neurobiology of the neuron as possible for one simple reason. The neurobiological events underlying the function of the neuron mirrors the task that the nervous system faces at all times: decision making. After all is said and done, the reality is that the neuron has only two functional options: to fire an action potential or not. I firmly believe in the notion that to understand how the nervous system creates, influences, and adapts behavior, you must understand the nature of the neuron and how it operates to decide to share information with other neurons. At the center of all this communication will be the integrative and decision-making abilities of the neuron. With an intuitive understanding of fundamental neuronal function, your appreciation of how the brain operates during normal and disordered behavior will hopefully be deeper and richer. Within the intra- and extracellular fluids are four unevenly distributed ions: sodium (Na+), chloride (Cl-), potassium (K+), and calcium (Ca2+). The concentration and electrical gradients developed by the unequal distribution of ions across the cell membrane create voltages or electrical potentials that generate electrical currents. Knowing how electrical currents and membrane potentials develop is foundational for understanding the mechanism behind neural signaling. Ion channels are complex arrangements of proteins that create a pore or tunnel through the impermeable phospholipid bilayer of the neuron. Ion channels are selective for different types of ions and can be gated in many ways. The different functional and structural properties of ion channels allow the nervous system to regulate and control the flow of ion current. All forms of neural signaling are produced by making short-lived changes to the Vm in either a depolarizing or hyperpolarizing direction. Regardless of the direction of change, Vm changes occur through the regulation of ionic currents through opened ion channels. The synapse is a composite structure consisting of a presynaptic segment on the neuron conveying the information, and a postsynaptic segment on the receiving neuron. Chemical synapses are capable of adaptable signaling and underlie the complex nature of behaviors mammals can produce. Neurotransmitters are key ligands (chemicals) that are expressed by a presynaptic terminal to influence the opening of postsynaptic channels (receptors). Four families or classes of neurotransmitters are recognized, including: amino acids, amines, neuropeptides, and gases. Neural integration describes how the neuron goes about deciding whether or not to "cast a vote" and participate in the working of the neuronal population. For example, if a door is opened to a room packed with people (area of high concentration), the people in the room will want to more into the hallway where there are few individuals and more space to stretch out (area of low concentration). In what way is the ion pump similar and/or different from other forms of ion channels Create your explanation so that someone unfamiliar with this topic would understand it. Be sure to include and briefly define the major players and their roles in this process. Begin your flowchart at the point where the axon hillock of the neuron is depolarized. Together you will now have a comprehensive flowchart that lays out the entire signaling process.

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Mechanoreceptors are a class of sensory ending that detect stretch treatment definition math purchase ropinirole 0.5 mg with visa, pressure medicine while breastfeeding purchase ropinirole with a visa, and other forms of mechanical or physical forces symptoms 5dpiui 2 mg ropinirole order mastercard. In the context of respiration medicine measurements discount 1 mg ropinirole mastercard, mechanoreceptors provide information on the mechanical status of the lungs and chest wall treatment 0f ovarian cyst buy ropinirole 1 mg overnight delivery. In this same example, stretchsensitive mechanoreceptors are co-activated to provide constant real-time feedback related to the mechanical status of the respiratory tissues during exercise. Medullary respiratory centers exert their influence on lung volume by way of motor axons controlling the intercostal muscles of the rib cage (cervical and thoracic spinal nerves), and the diaphragm (phrenic nerve innervation). Such is the case when individuals who are brain dead after severe disease or trauma continue to live and breathe for long periods of time. The respiratory neural centers, like the cardiovascular centers, are found within the reticular formation at the core of the medulla (Saper, Lumsden, & Richerson, 2013). Distinct respiratory networks are found in both the dorsal and ventral areas of the medulla, with each group operating to control respiratory function in unique ways. Together, the ventral and dorsal groups comprise the medullary respiratory center (Smith, Morrison, Ellenberger, Otto, & Feldman, 1989). Dorsal respiratory group neurons modulate the depth of breath though the monitoring of (a) stretchsensitive baroreceptors in the respiratory vasculature, and (b) chemoreceptors. Ventral respiratory group neurons appear to control and coordinate respiratory motor outputs to drive the rhythm of breathing. Of unique importance in the ventral respiratory group is a region of the medulla called the preBötzinger complex. The pre-Bötzinger complex has been shown to be the "seat" of mammalian respiratory rhythms (Smith et al. These neurons are capable of setting the pace of coordinated respiratory motoneuron activity independent of any other source of input. In mammals with more complex respiratory behavioral repertoires, breathing must also be coordinated with voluntary actions such as vocalization and swallowing, and with nonvital reflexive behaviors such as vomiting, coughing, hiccupping, and sneezing (Ludlow, 2011). To achieve these behaviors, medullary respiratory neurons in the dorsal and ventral groups also integrate inputs from the pons and the cerebrum to momentarily suspend or alter the rhythm and depth of respiration. Such suspension of automatic respiratory function is needed to meet the conditions necessary to perform voluntary or nonvital respiratory actions. In summary, you can see that the function of the medulla is remarkably diverse, including functions that are central for sustaining life and for generating behaviors that are commonly associated with speech, voice, and swallowing. The medullary respiratory center is comprised of the pre-Bötzinger complex and the ventral and dorsal respiratory groups. Respiratory control center neurons are located within the reticular formation of the brainstem and interact to mediate the depth and rate of breathing. Having an awareness of these patterns will serve you well if working with neurologic populations in rehab centers or long-term care facilities. Hallmark characteristics of the syndrome include loss of temperature and nociceptive (pain) sensation from the contralateral side of the body below the neck and on the ipsilateral face. Patients also will present with loss of the gag reflex, vocal hoarseness, and speech and swallowing deficits. Damage to the descending autonomic pathways will result in sympathetic drive deficits (loss of the "fight or flight" response). Deficits emerging from these lesions include dizziness (vertigo), nystagmus (rapid eye twitching), vomiting, and cerebellar ataxia (discoordination of movement). Because of damage to these structures, the following deficits are often noted: (a) loss of somatosensation from the contralateral side of the body relative to the site of damage, (b) contralateral loss of movement due to damage of the corticospinal tract in the pyramids, and (c) paralysis of the ipsilateral tongue body due to damage of the lower motor neurons innervating the lingual muscles. The anterior median fissure is a prominent groove in the midline dividing the ventral medullary surface evenly left to right. On either side of the anterior median fissure are the next two prominent landmarks known as the pyramids and the olivary eminence. The pyramids are swellings or ridges just lateral to the anterior median fissure that contain axon fibers of the principal descending motor pathway between the motor cortex in the cerebrum and the spinal cord - the corticospinal tract. At a point roughly two thirds of the way down the medullary ventral surface is a region in the midline between the left and right pyramid that appears smooth and flat. This smoothed ventral region is the pyramidal decussation and reflects the point where the great majority of corticospinal fibers within the pyramids cross the midline to continue descending into the contralateral aspect of the spinal cord. The term decussation means literally to "crisscross" from one side of the midline to the other. This crossing over of descending motor fibers at the pyramidal decussation is why one side of the brain controls the movement of the opposite side of the body. Decussations and contralateral control are a common feature of mammalian nervous systems. A third prominent landmark of the ventral medulla is the olivary eminence, situated lateral to the pyramids. The olivary eminence consists of an underlying nucleus known as the inferior olivary complex (often abbreviated as the inferior olive). The last key landmark of the ventral medulla is where the nerve roots of the hypoglossal nerve exit the brainstem between the pyramids and the olivary eminences on each side. The dorsal-most ridge on the lateral aspect of the medulla represents the ascending afferent fibers of the dorsal columns from the spinal cord (cuneate and gracile fasciculi). The accessory nerve innervates muscles of the neck, driving muscle contraction for rotation and flexing of the head. The vagus is a massive cranial nerve system that mediates a wide variety of sensory and motor behaviors, both somatic and autonomic in quality. Importantly for our purposes, the vagus nerve underlies the exquisite motor control and sensory innervation of the larynx, necessary for voice production and swallowing control. The two most obvious dorsal surface ridges are the tubercles of the cuneate and gracile nuclei. The cuneate and gracile are key sensory nuclei that receive tactile and proprioceptive from the outside world from the body below the neck. These nuclei form a key relay and integration location along the somatic sensory pathway and are discussed in detail in a later chapter. Nerves are color coded by gross function: red = motor, blue = sensory, and purple = mixed (sensory and motor). The V-shaped gap of the obex happens to be the lowest part of a fluid-filled region situated between the brainstem and the cerebellum called the 4th ventricle. Before beginning our description of the key internal features of the medulla, it is important to always keep in mind that when studying a section of tissue, the structures described are all 3-D when intact. The illustrations of brainstem slices shown in this textbook are simplified representative 2-D slices of the medulla (or pons or midbrain) at key locations along the rostro-caudal axis. What this means is that within different slices, the same labeled structure will have a differently shaped outline and position in the sliced sections. A silly way to wrap your head around this idea is to think about slicing up a marbled pound cake (chocolate and vanilla cake swirled together). As you slice the cake and look at the surfaces of each slice, the swirling pattern changes from slice to slice, because the overall shape and size of the swirl pattern is only fully present when the cake is intact and unsliced. Superior cerebellar peduncle Medial eminence Middle cerebellar peduncle Rhomboid fossa Inferior cerebellar peduncle Vestibular area Facial colliculus Trigone of hypoglossal nerve Trigone of vagus nerve Tubercule of cuneate nu. Internally, the chief landmark is the pyramidal decussation in the ventral region of the tissue. In the pyramidal decussation, descending left corticospinal fibers shift to the right side and vice versa as they proceed into the spinal cord to provide motor innervation to spinal lower motoneurons. The corticospinal decussation is not to be confused with another more prominent crisscrossing pattern that is found more centrally throughout much of the lower medulla called the internal arcuate fibers. The internal arcuate fibers consist of axons of neurons originating in the cuneate and gracile nuclei that pass in a curved manner across the midline of the medulla to form the contralateral ascending sensory tract known as the medial lemniscus. Note that at this transitional level of the medulla, we can clearly identify the fibers (in cross-section) of the anterolateral system (nox- ious and thermal inputs) as well as the ascending afferent fibers (also in cross-section) of the cuneate and gracile fasciculi (tactile and proprioception), and sensory fibers belonging to the trigeminal cranial nerve system. These include the hypoglossal nucleus, the accessory nucleus, and the dorsal nucleus of vagus. Internally, though, the layout of structures takes on a more orderly and symmetrical appearance. Starting at the midline, these are the cuneate, gracile, and spinal trigeminal nuclei. The neurons of the cuneate nucleus are responsible for conveying sensory inputs to Gracile Fasc. Representative axial section of the caudal-most medulla in the region of the pyramidal decussation. The gracile nucleus, located lateral to the cuneate, receives tactile and proprioceptive inputs via the gracile fasciculus from the lower trunk and legs, conveying these inputs to the thalamus as well. The lateral-most of the three prominent nuclei at this level of the medulla is the spinal trigeminal nucleus. Other prominent nuclei and structures at this level of the medulla include (1) the nucleus ambiguus, the dorsal motor nucleus for the vagus, (2) the hypoglossal nuclei, which innervate tongue muscles, (3) the solitary nucleus, a key sensory nucleus mediating the sensation of taste and tactile inputs from the laryngeal region, (4) the inferior olivary complex, whose cells form the olivary eminence on the ventral medullary surface, and (5) the reticular formation, the undifferentiated region of cells at the center of the cross-section. Note that the nucleus ambiguus is considered by some anatomists to extend inferiorly deep through the lower medulla. Of the myriad fiber tracts to and from the spinal cord passing through the medulla, there are three key tracts to be familiar with: the medial lemniscus, the anterolateral tract, and the corticospinal tract (Haines, 2013). The medial lemniscus (Latin for "ribbon-like") is found in the ventral and midline area of the medulla and are the axons of contralateral neurons originating in the cuneate and gracile nuclei. The medial lemniscus is a massive sensory pathway that forms the second leg of a three-neuron system transmitting tactile and proprioceptive inputs from the body below the neck. Lastly, we have the corticospinal tract, which comprises the mass of the pyramids on the ventral and midline aspect of the medulla. The corticospinal tract is a descending pathway that transmits motor signals from the primary and premotor regions of the cerebral cortex down to the lower motoneurons in the ventral gray of the spinal cord. The hypoglossal, solitary nucleus, nucleus ambiguus, and spinal trigeminal nucleus are still present, but the cuneate and gracile nuclei are no longer visible at this level. Two new gray matter regions emerge in the dorsal and lateral aspect of the medulla at this level: the inferior and medial vestibular nuclei. The vestibular nuclei also form a major input to balance control regions of the cerebellum. The reticular formation has expanded as well and now surrounds several of the previously mentioned nuclei. During dissection of the medulla, you can tell right away that you are in the rostral end when you start to notice the dorsal surface of the tissue take on a wide V-shaped appearance. This V-shaped region is the lowest corner of a diamond-shaped space known as the rhomboid fossa. The rhomboid fossa is situated between the dorsal surfaces of the pons and medulla of the brainstem and the anterior cerebellum. The rhomboid fossa also happens to be the fluid-filled space of the 4th ventricle (function of the ventricles is cov- ered in Chapter 5). Examining the broadened regions of the medulla, we can see the appearance of the anterior and posterior cochlear nuclei lateral to the position of the enlarged vestibular nuclei. The only other of the previously described nuclei still visible at this rostral level of the medulla are the nucleus ambiguus, the solitary nucleus, the inferior olive, and a small segment of the spinal trigeminal nucleus. The medial lemniscus, anterolateral tract, and the corticospinal tract remain in the same general location within the medulla when compared to previous levels. Pons Moving rostrally from the medulla, we find the next major segment of the brainstem - the pons. It is bounded caudally by the medulla, rostrally by the mesencephalon (midbrain), and posteriorly by the cerebellum. The pons is comprised of two distinct segments along the ventral-dorsal axis of the brainstem. The basilar pons consists primarily of axon fibers crisscrossing one another in both the vertical and horizontal directions, with minute nuclei scattered among the intersecting fibers. The principal fiber tracts found within the basilar pons are the corticospinal and corticobulbar tracts that innervate skeletal muscle tissue of the body, and the pontocerebellar tracts that innervated the cerebellum. The gray matter of the tegmentum consists of cranial nerve nuclei and assorted cell groups or clusters that mediate a wide range of activity from sound processing, to attention, to motivation. In addition, the pons operates as the key anatomical bridge between select frontal lobe regions of the cerebrum, the spinal cord, and the neural circuitry of the cerebellum. The crucial connectivity between the frontal cerebrum, the spinal cord, and the cerebellum via the pons is active during the learning of new skills and the refinement of coordinated movements (Amaral, 2013). The pons also houses several noncranial nerve nuclei such as the superior olivary complex and the locus ceruleus. The superior olive is a key relay along the sound-processing central auditory pathway. Lastly, the pons plays a crucial and life-sustaining role in respiratory function through the operation of clusters of cells within the pontine reticular formation (Smith et al. Two complementary groupings of respiratoryrelated cells, the pneumotaxic center and the apneustic center, together make up the pontine respiratory region (Saper et al. As mentioned during our discussion on the general function of the medullary respiratory centers, the pons is a major source of modulatory input to these medullary areas. The specific source of these inputs comes from the pontine respiratory groups within the reticular formation of the tegmentum. The pontine respiratory groups operate through direct axon connections with the medullary respiratory centers to modify respiratory rhythms and breathing depth. For example, the apneustic center of the pons promotes inspiration by exciting cells of the medullary respiratory center, while the pneumotaxic group limits inspiratory activity by inhibiting those same medullary centers. The pneumotaxic center is of special interest to speech pathologists because these are the cells actively coordinating breathing during chewing and swallowing. The neural control of respiratory function is unique among other visceral functions. As already noted, mammals routinely use the inhibitory effects of the pneumotaxic center to momentarily suspend the regular rhythms of life breathing to swallow and cough. In humans, the ability to volitionally alter brainstem respiratory activity reaches new heights with the capacity to produce speech, sing, or play a wind instrument like the bassoon, clarinet, or euphonium.

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