Neuroscience 26 Exam 2 Spring, 2007

Neuroscience 26 Exam 2 Spring, 2007 Exam book 1. 1. [3 points each x 3 = 9 points] Define or describe any 3 of the following 4 items in a single phrase or sentence: a. receptive field (be sure to say what has a receptive field) b. 11-cis retinal c. visual cortex >blob= d. spinothalamic tract 2. [4 points each x 2 = 8 points] Choose any 2 of the following 3 features of the nervous system we have studied. In a sentence or two, say briefly what its functional significance is; specifically, what funtion or property of the nervous system would be lost or reduced if the feature were eliminated? A. Antagonism between center and surround responses of retinal ganglion cells B. Opiod receptors in the brain C. Magnocellular visual pathway 3. [6 points x 2 = 12 points) Short answer questions. Choose any 2 of the following 3 questions; answer in a few sentences each. A. How does each of the following affect binocularity in the visual cortex (>binocularity= here means the numbers of neurons whose responses can be driven by the left eye, the right eye, or both eyes): (1) Monocular deprivation (keeping one eye closed); (2) alternating monocular deprivation (changing which eye is closed each day); (3) binocular deprivation (e.g. raising the animal in the dark). Each of these treatments is given during the >critical period= around the 3rd through 6th postnatal week. (Over) B. What is the immediate, direct action of light in the eye? What kind of chemical signalling occurs as a result of the direct action of light, and what permeability change in the photoreceptor membrane results? C. What is the rationale for cooling the visual cortex (not all the experimental details), as a way to test whether orientation selectivity results directly from lateral geniculate inputs vs. intracortical circuitry? 4. (2 x 8 points = 16 points) Short essay questions. Choose any 2 of the following 3 questions; answer in a short essay of less than a page. A. Discuss the AHebb Rule@ and describe how it can explain refinement of sensory projections, e.g. formation of ocular dominance zones B. Describe how the center and surround responses of an >on=-center, >off=-suround bipolar cell are generated by circuitry in the retina. Include both a diagram and an explanation in words. C. Consider the Melzak & Wall pain circuit shown below. AP@ is the pain projection neuron in the spinal cord. Describe the circuit by answering the questions below. - What sensory inputs are represented by A and A= different inputs, but which A and which is A= doesn=t matter) and its connections were eliminated, what aspect of perception and its modulation (two one is - If neuron B pain by other stimuli would be affected? - What physiological type of synapse is represented by S (i.e. the synapses made by cell B)? - Where does the axon of cell P terminate? NEUROSCIENCE 26 MID-TERM TEST #2 Spring 2007 1. (6 points: 2 pts each) Define or describe any 3 of the following 4 items in a sentence or two. A. T1R2+R3 B. lateral lemniscus C. FM sweep D. Globus Pallidus, internal segment 2. (12 points: 4 pts each) Contrast any 3 of the 4 pairs below in a sentence or two each (i.e. state an important difference between the two): A. Cortical vs. substantia nigra inputs to the striatum. B. Golgi tendon organ vs. spindle C. eserine vs. curare D. apomorphine vs. amphetamine 3. (2 points) Complete the following Miller=s analogy (use as many words as needed; feel free to show your reasoning): ACorticofugal is to ascending as the vestibulospinal tract is to _______.@ 4. (10 points) Answer either of the following: A. Recall the paper by Tillerson et al. Evaluating 6OHDA lesions in rats. A main result of the paper is shown in the figure. Explain briefly how these data were obtained, and what this figure shows, what the data mean, and what the implications are for brain function and treatment of disease. OR B. The paper by Zhao et al. investigated the effects of various transgenic taste receptor treatments. Discuss their rationale for doing the study, what they found, and how they interpreted the data, and consider ways in which the study could be improved. 5. (4 points) In a word or phrase, identify which aspect(s) of auditory function is/are primarily signaled by activity in each of the following pathways: A. Superior olive (human) B. CF-CF area (bat) C. FM-FM area (bat) D. Pinna (human) 6. (4 points) Explain what the saturation curve figure indicates. 7. (6 points) Describe how activation of D1 receptors in the striatum can result in myosin-actin binding in your foot. 8. (4 points) Explain why botulinum toxin would be expected to have different effects on the heart versus respiratory muscles. 9. (4 points) Explain in two sentences how the gamma motor neurons contribute to muscle function. 10. (24 points: 4 pts each) Contrast any 6 of the 8 pairs below in a sentence or two each (i.e. state an important difference between the two): A. Velocity coding vs. distance coding in the bat B. Transduction at taste receptor cells vs. transduction at inner hair cells. C. Neural mechanisms for spicy vs. sweet sensation D. Bmaxvs. Kd E. D1 receptor function vs. D2 receptor function F. Adenylate cyclase vs. IP3 G. Dopamine-beta-hydroxylase vs. dopamine decarboxylase H. GABAa receptor versus NMDA receptor Extra credit question (2 points): The chorda tympani nerve is a branch of the 7TH cranial nerve that runs past the inner side of the tympanic membrane, through the middle ear. It is, ironically, involved in: Vision Touch Smell Taste Pain