UCSD COGS-201 Winter, 2016 Final exam questions
1. Based on the Durstewitz/Seamans article discussed in class, provide a description of the model for schizophrenia. Strong answers will combine knowledge of how the amount of DA released can impact how it activates different types of DA receptors having different properties and, in turn, how that impacts the strength of intrinsic versus extrinsic inputs and movement between cell assemblies.
DA, DA release, D1, D2, cAMP, affinity, distribution, intrinsic, extrinsic, energy, assembly, and D1/D2 state are all terms that should probably be included. Maximum answer length – 1.5 bluebook pages.
2. The Markram/Tsodyks article provides a different perspective on the effects of repeated pairing of action potentials for a presynaptic and postsynaptic cortical neuron. Explain what is meant by ‘redistribution’ versus ‘potentiation’ of synaptic strength and what experimental manipulation allowed them to make this distinction. What range of pairing intervals (not frequencies) produces redistribution? Maximum answer length – 2/3 bluebook page.
3. Describe the phenomenon of hippocampal phase precession. Good answers will describe the spatial firing fields of at least3hippocampal neurons, the relation of these fields to each other, characteristics of the hippocampal LFP during locomotion, and, most importantly how these relate to each other. Obviously, an assessment of spiking order as it relates to hippocampal theta phase and the ordering of firing field peaks will be required. Feel free to use diagrams. Maximum answer length – 1.5 bluebook pages.
Bonus (10 points) - Explain how phase precession, combined with the continuum of place field sizes between dorsal and ventral hippocampus and combined with the phenomenon of the ‘hippocampal travelling wave’ yields a time-varying representation of the animal’s trajectory. What feature of trajectory encoding varies over the period of one cycle of theta travelling from dorsal to ventral hippocampus? Maximum answer length – 1 bluebook page.
4. According to Lauwereyns and Hikosaka, what neurophysiological phenomena results in reduced saccade reaction times when reward is expected? In your answer, be sure to refer to firing dynamics across time and to the brain region involved. Maximum answer length – 1 bluebook page.
Bonus (2 points) – According to Hikosaka, can DA neurons support encoding of information beyond current error in expected reward? Yes/No (circle one).