Neurophysiology

Question 1

What are dendrities

Answer 1

Branched extensions that receives input from other neurones

Question 2

What is myelin?

Answer 2

Insulation of the axon making action potential non diminishing

Question 3

What is an astrocyte?

Answer 3

A cell used to housekeep to take away excess glutamate and monitor activity in the synapse

Question 4

What is back propagation?

Answer 4

Action potential flowing backwards into the dendrites

Question 5

Where are action potentials made?

Answer 5

Axon hillock

Question 6

Where do EPSP and IPSP travel from and to

Answer 6

From dendrites to the soma

Question 7

What does action potential trigger?

Answer 7

Influx of calcium ions into presynaptic terminal causing movement of molecular machinery Ligand gated channels open and release influx of sodium

Question 8

What is direct gating/Inotropic

Answer 8

Conformational change occurs in the shape of the receptor(channels have different sub-types)

Question 9

Indirect gating/Metatropic

Answer 9

Use of G protein usually activated lutamate or GABA which changes the metabolic state of the cell

Question 10

What are the 2 Types of synapses?

Answer 10

type I and type II
The difference between the synapses is the postsynaptic density
In the type I the population density is a bunch of proteins which hold the receptors

Question 11

3 main receptors on Type I

Answer 11

AMPA receptor bind to glutamate and tend to depolarise the membrane
NMDA receptors have multiple sites and can modify easily and bind to glutamate put require a co-agonist(glycine), the receptor is ligand and voltage gated
Metabotropic receptors are g protein coupled controlling metabolism

Question 12

What are the 3 classes of inotropic receptors

Answer 12

AMPA, NDMA and KA

Question 13

What are meabotropic glutamate receptors/mGluRs?

Answer 13

A 7 transmembrane regions

controls brain cell function in seconds(neuromodulator) and is connected to secondary men

Question 14

What is G proteins signalling

Answer 14

G proteins signal causing the activation of phospholipase C so that hydrolyses occurs for calcium to be released

Question 15

What excitatory glutamate receptors do?

Answer 15

They allow passage of sodium ions and sometimes calcium ions and produce EPSP
Agonist:glutamate, AMPA and KA
Antagonist-CNQX,NBQX

Question 16

NMDA glutamate receptor

Answer 16

Mediates slower synaptic responses because of conductance to potassium
The channel Na+, K+ and ca2+
Can cause Exocitoxicity

Question 17

What is Exitotoxicity?

Answer 17

When the LTP and LTD is activated too much

Question 18

What does magnesium ions do to NDMA receptor?

Answer 18

Magnesium ion Blocks pore and depolarisation happens magnesium is less attracted and allows for passage of ions

Question 19

NMDA dual gating

Answer 19

Glutamate and depolarisation is needed to open
Also glycine is required as a co-agonist
Calcium and sodium enter the cell and potassium leaves the cell

Question 20

What does GABAa do?

Answer 20

GABAa binds to sites between sub units makes the cell more hyper polarised

Question 21

GABA effect time

Answer 21

GABAa is around 50-60 milliseconds

GABAb is around 500-1000msec

Question 22

Name the sensory modalities

Answer 22

Vision
smell
taste
touch
thermal sense
pain
hearing
retina

Question 23

What is psychometric functions?

Answer 23

Fechner defined psychometric functions which is how big the stimulus compared to the intensity of sensation of what they feel

Question 24

What are sense organs?

Answer 24

Sense organs are made by combining multiple different receptors
Example combination of mechanoreceptors gives fine sense of touch

Question 25

What are rods?

Answer 25

Rods check black and white colour

Question 26

What are cones?

Answer 26

Cones sense the amount of red, blue and green light

Question 27

Types of firing pattern?

Answer 27

One type of firing pattern is one that fires at the start of a signal then calms down or fires at the start of a signal and adapts rapidly
First type is to tell that there is detection like someone pressure the skin(Rapidly adapting receptor)
The second type is to maintain the firing to show that pressure of the skin is still occurring(slow acting receptor)

Question 28

Types of code

Answer 28

Rate code=Number of spikes
Count code=How many spikes
Temporal code=Precise spiking
Phase code: Spike versus a rhythm
Population code=Spikes between different neurones

Question 29

What features does sensory neurones have?

Answer 29

receptive fields-region in the sensory periphery within which stimuli can influence the electrical activity of sensory cells.
spatial domain
many spatial overlap

Question 30

How does relay neurone integrate sensory neurones?

Answer 30

The red receptor cell being excited causing the action potential to fire in the relay neurone which switches on the inhibitory neurones
The cognate red relay cell inhibits neighbours causing inhibitory surround

Question 31

How is complex information processed in relay neurone?

Answer 31

Convergence of inputs(V4)- receives information through multiple neurones

Question 32

What happens in the retina

Answer 32

The retina encodes components and the brain decodes components

Question 33

What type of modulation does relay allow?

Answer 33

It allows top down modulation-Modulation of neural activity in neurons in lower-order sensory or motor areas based on an individual’s goals.