Synapse 2

Question 1

What do dendrites do?

Answer 1

Help compute the response of the neuron

Question 2

How do dendrites help compute the response of the neuron?

Answer 2

Timing and multiplicity of inputs

Dendritic morphology and end bulb position

Different types of electrical activity

Question 3

What’s dendritic morphology?

Answer 3

Spines

Branching

Length

Question 4

What does position of dendritic end bulbs do?

Answer 4

Governs input to cell body and AP output

Question 5

Single EPSP:

Answer 5

Single input of action potential

No action potential triggered

Question 6

Spatial summation:

Answer 6

Multiple inputs of action potential

Question 7

Temporal summation:

Answer 7

Train of inputs of action potential

Question 8

What triggers an action potential?

Answer 8

2 coincident EPSP - summed

Question 9

What stops 2 EPSP triggering an action potential?

Answer 9

Adding a coincident IPSP

Question 10

IPSP

Answer 10

Inhibitor postsynaptic membrane potential

Question 11

EPSP

Answer 11

Excitatory postsynaptic membrane potential

Question 12

What governs output of a neuron?

Answer 12

Summation of EPSPs/IPSPs

Question 13

What prevents a neuron from firing?

Answer 13

IPSP

Question 14

What determines level of excitation of a neuron?

Answer 14

Dendrite structure and synapse location

Question 15

What does the strength of postsynaptic membrane potential depend on?

Answer 15

Placement of excitatory or inhibitory nature of the inputs

Question 16

What length spines of dendrites produce a lower EPSP?

Answer 16

Longer spine

Question 17

Electrical activity in dendrites:q

Answer 17

EPSP and IPSPs are passive electrical activity - set axonal response

Question 18

What forms of electrical activity in dendrites are active self propagating?

Answer 18

The dendritic spike

Question 19

What do dendritic spikes do?

Answer 19

Boost the depolarisation in dendrites

Can leak into cell body to stimulate an action potential

Question 20

When do dendritic spikes especially occur?

Answer 20

When stimulation is intense in space or time (coincidence detection)

Question 21

What can dendritic spikes do on post synaptic membrane?

Answer 21

They can act locally on post synaptic membranes

Generate long term potentiation - in learning and memory

Question 22

What’s involved in post synaptic integration?

Answer 22

Computation

Question 23

What is computation?

Answer 23

Spatial and temporal summation of multiple PSPs / dendritic spikes is required to achieve threshold

Includes effects of dendritic spine and tree morphology

Question 24

What does post synaptic integration act as?

Answer 24

Decision making process

Question 25

What is memory due to?

Answer 25

Strengthened synapses New synapses

Question 26

What does long term potentiation include?

Answer 26

EPSP is increased

Question 27

What may result in stronger synapses?

Answer 27

Increased neurotransmitter release Increased sensitivity Increased number of receptors Increased size of post synaptic machinery

Question 28

What causes reception of signals?

Answer 28

Highly branched processes Dendrite tree and dendritic spines

Question 29

What is long term potentiation associated with?

Answer 29

Making new synapses in vivo on dendritic spines

Question 30

What is long term potentiation?

Answer 30

Synaptic connections become stronger with frequent activation

Question 31

What’s involved with the formation of a new dendritic spine?

Answer 31

Filopodia formation Thin spine formation - formation of new synapse Spine head widening Multiple spine formation - increase in synaptic transmission

Question 32

What does neuroplasticity result in?

Answer 32

Stronger/weaker synapses More/less synapses

Question 33

How does neuroplasticity to result in stronger synapses?

Answer 33

Upregulation of neurotransmitter secretion Receptor expression Phosphorylation control (signalling)

Question 34

How ones neuroplasticity result in more synapses?

Answer 34

Sprouting Branching Dendritic spine formation

Question 35

What is changes in synaptic transmission driven by?

Answer 35

Local signalling pathways

Question 36

What is structural changes driven by?

Answer 36

Signalling to the nucleus - driving transcription

Question 37

What is Hebb’s learning rule?

Answer 37

That there is a learning pathway to a sequence Learning is a predicting sequence

Question 38

How does Hebb’s learning rule suggest synapses strengthen/stabilise?

Answer 38

Correlated pre/postsynaptic activities

Question 39

How does Hebb’s learning rule suggest synapses weaken?

Answer 39

Uncorrelated pre/postsynaptic activities

Question 40

What may synaptic change be due to?

Answer 40

Increases and decreases in synaptic strength leading to behavioural plasticity

Question 41

What is similar between behavioural learning and synaptic plasticity?

Answer 41

Temporal and molecular properties

Question 42

What does behavioural learning appear to use?

Answer 42

Similar underlying cellular and molecular mechanisms E.g. addiction

Question 43

What do addictive drugs cause?

Answer 43

Large release of dopamine in reward centre

Question 44

What does dopamine do in addictive drugs?

Answer 44

Reinforces repeat and return behaviours to the drug

Question 45

What seems to be the start of behavioural changes in Addie drugs?

Answer 45

Synaptic plasticity in glutaminergic synapses

Question 46

What can addictive drugs do to the frontal lobe?

Answer 46

Less active executive control

Question 47

Why is normal dose of pleasure less effective in addictive drugs?

Answer 47

Down regulation of transmission (reduced vesicles) Down regulation of reception (reduced receptors)

Question 48

Examples of multi-neuron networks:

Answer 48

Feedforward excitation and inhibition Lateral inhibition Feedback/recurrent excitation and inhibition Convergence/divergence

Question 49

What do inhibitory microcircuits include?

Answer 49

Interneurons Short axons Fast acting Inhibition mostly by GABA

Question 50

Location of central pattern generators:

Answer 50

Spinal cord (+elsewhere)

Question 51

What do central pattern generators do?

Answer 51

Communication in white matter in spinal cord

Question 52

What’s involved in regional specialisation and communication?

Answer 52

Central pattern generators

Question 53

Give an example of an inhibitory interneurons:

Answer 53

Stimulation of touch can help block transmission of pain impulses to brain

Question 54

What results in a higher degree of convergence in a neuron?

Answer 54

More dendrites

Question 55

What is neuronal divergence?

Answer 55

Information from a single neuron is passed to a number of other neurons simultaneously No loss of signal strength