Question

3.   Compare and contrast an action potential and a local post-synaptic potential in terms of where they occur on a neuron, the change in charge, how they propagate through a neuron. (3)

6.   What is an EPSP and IPSP? Provide a definition, not just spelling out the acronym. (2) Provide a specific example of how each can be generated in a neuron. (4)

8.   Imagine humans have a single hypothetical neuron that controls the decision to get out of bed. This neuron receives many inputs from other neurons; some generate EPSPs and some generate IPSPs. When this neuron fires an action potential, the person gets out of bed in the morning to start their day. Provide 5 different types of input that would generate EPSPs or IPSPs but ultimately result in a decision to get out of bed. For example: “A weak EPSP occurred when my dog licked my face, so I knew he needed to go for a walk.”

Answer 1

Action potential : 1. Usually initiated at the axon hillok

2. Self propagating without voltage decrement

3. All or non principle is fallowed during

4.No voltage summation

Post synaptic potential : 1 initiated close to the synapse

2. Passive propagating with dec in the voltage

3. Temporal and spatial voltage summation

(postsynaptic potentials require activation of ligand-gated ion channels located on the postsynaptic membrane, whereas action potentials require activation of voltage-gated ion channels located at very high concentrations along the axon hillock and at lower concentrations along the remainder of the axon)

EPSP :  EPSP is received when an excitatory presynaptic cell, connected to the dendrite, fires an action potential.  

Generated by the depolarization

IPSP : An inhibitory postsynaptic potentials (IPSP) is a temporary hyperpolarization of postsynaptic membrane caused by the flow of negatively charged ions into the postsynaptic cell

Generated by the hyper polarization

Inputs provided to get out of bed : dog licking the face,keeping an alarm a week ago, switching of fan to get out of bed ect..