Synapse 2

Question 1

What is dendritic integration

Answer 1

The process of combining excitatory and inhibitory inputs

Question 2

What can determine the level of excitation?

Answer 2

Dendrite structure and synapse location. This special arrangement matters in the generation of an action potential.

Question 3

What influences PSP summation?

Answer 3

Dendritic spine morphology. Longer spines produce a lower EPSP, and shorter spines produce a larger EPSP.

Question 4

How do dendrites help compute the response of the neuron?

Answer 4

Through timing and multiplicity of inputs.
Dendritic morphology and position of end bulbs.
Different types of electrical activity.

Question 5

Explain what is mean by a dendritic spike

Answer 5

Dendritic spikes occurs when there is an intense stimuli which triggers depolarisation in the dentrite or cell body. They can stimulate an action potential

Question 6

Name the different types of dendritic electrical activity

Answer 6

Excitatory Post Synaptic Potential, Inhibitory Post Synaptic Potential and dendritic spikes.

Question 7

What is long term potentiation? and what is it associated with?

Answer 7

It is a persistent increase in the strength of the synapse following high frequency stimulation.

Associated with making new synapses on dendritic spines.

Question 8

Describe how a stronger synapse is made?

Answer 8

Up-regulation of neurotransmitter secretion, increased receptor expression and signalling control.

Question 9

Describe the process of forming new synapses

Answer 9

Occurs via sprouting, branching and dendritic spine formation.

Question 10

How are short term changes in synaptic transmission driven?

Answer 10

By local signalling pathways.

Question 11

How are long term structural synaptic changes driven?

Answer 11

By signalling to the nucleus. This drives transcription to generate new synapses

Question 12

What is synaptic plasticity?

Answer 12

The changes that occur at synapses. Either making new synapses or strengthening current synapses

Question 13

What is feedforward excitation?

Answer 13

A chain of excitatory neurons

Question 14

What is feedforward inhibition?

Answer 14

An inhibitory neuron between two excitatory neurons

Question 15

Give an example of feedforward inhibition and explain how it works

Answer 15

The knee jerk reflex.
Sensory neurons convey information about the reflex to motor neurons, the motor neurons that supply the quadriceps are stimulated and the motor neurons that supply the hamstring are inhibited.

Question 16

What is lateral inhibition and give an example

Answer 16

Where a neuron is capable of inhibiting the neurons next to it. An example can be with pain, the lateral inhibition can sharpen the responses and allows the body to directly locate the source.

Question 17

Describe what feedback/recurrent inhibition is and name an example

Answer 17

This is where the feedback loop goes through an inhibitory neuron. An example is the inhibitory control of pyramidal cells of the cerebral cortex.

Question 18

Give an example of inhibitory interneurons

Answer 18

Pain gating in the spinal cord. Stimulation of touch can help to block transmission of pain impulses to the brain

Question 19

Describe what convergence/divergence multineuron networks are and give an example

Answer 19

Where several neurons converge into one neuron and this diverges onto several neurons.
An example is in the retina. Information from several neurons converge into one.
An example of neuronal divergence is in the knee reflex jerk.