Cell and Molecular Neurobiology - Biology 304

Course Syllabus

Homework Assignments

(How to use NeuroSim.)

Homework #2
Due Thursday November 12, 1998

1. IPSP Reversal Potential Determine the reversal potential of the inhibitory connection from neuron 1 to neuron 2 and explain why the amplitude of the IPSP is zero at the reversal potential. To determine the reversal potential you will need to change the resting membrane potential of neuron 2. Use NeuroSim Network File syn-inh.

2. Synaptic Integration Open NeuroSim Network file - hwork2.ntw. The initial configuration has amp of Pulse 1 set to 40 (target = neuron 5) and the amp of Pulse 2 set to zero. Make sure these parameters are correct. Start simulation. Note the response that stimulating neuron 5 has on neuron 1. Now set amp of Pulse 2 to 30, target neuron of Pulse 2 to 6 and run simulation again. How has the response induced in neuron 1 by stimulating neuron 5 changed? Why? Finally, set target neuron of Pulse 2 to 7 and run simulation. What effect has the synaptic input from neuron 7 had on the response produced in neuron 1 by stimulating neuron 5? Why does the same strength synaptic input (number of action potentials in neuron 6 and 7) have a different effect on the response in neuron 1 to stimulating neuron 5? Note that neuron 1 represents the soma of a neuron, and neurons 2, 3 and 4 comprise its non-spiking (passive membrane) dendrite.

3. Functional Organization of Cotransmission Systems: Lessons from Small Nervous Systems. Invertebrate Neuroscience 1:105-112 (1995). What are the implications of cotransmission of neuromodulatory peptides with respect to synaptic integration and the communication between neurons?

Homework #3
Due Tuesday December 8, 1998

1. What function do G-proteins serve in second messenger systems and how are they regulated?

2. Why does the reciprocal inhibitory network simulated in NeuroSim Network file recip-3 oscillate?

3. What does the figure below suggest about the mechanism that regulates activity (gating) of nonspecific cation (e.g. calcium, barium etc.) channels in the bag cell neurons of Aplysia. Note that the experiments illustrated in the figure were performed on inside-out patches excised from the cell bodies of single bag cell neurons.
Abbreviations: ATP - adenosine triphosphate, AMP - adenosine monophosphate, ADP - adenosine diphosphate, PKC inhibitor - peptide that inhibits the action of protein kinase C, PP1 - protein phosphatase, C - channel in closed state, O - channel in open state.

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