olfactory and taste

Question 1

describe the drift-diffusion model

Answer 1

start at a middle point. based on sensory information received at each point in time (evidence) go up towards one direction (correct decision) or go down towards another direction (wrong decision) until threshold reached

Question 2

what is David Marr’s 3 levels of analysis

Answer 2

1. computational problem
2. algorithm
3. physical implementation

Question 3

which area of the brain is important for innate behaviour in vertebrates?

Answer 3

amygdala

Question 4

which area of the brain is important for innate behaviour in invertebrates?

Answer 4

lateral horn

Question 5

which area of the brain is important for learned behaviour in vertebrates?

Answer 5

piriform cortex

Question 6

which area of the brain is important for learned behaviour in invertebrates?

Answer 6

mushroom body

Question 7

which receptor is used for sour tastants? describe.

Answer 7

ionotropic receptor
sour = H+
H+ enters ion channel and causes H+ sensitive channel to open –> amplifies signal

Question 8

which receptor is used for salt tastants? describe.

Answer 8

ionotropic receptor = Na+ channel

neurons depolarise when Na+ enters cell

Question 9

describe the taste circuitry

Answer 9

1. taste buds on tongue send axons through cranial nerves to solitary nucleus of brain stem
2. neurons at brain stem send signals to ventral posterior medial nucleus of thalamus
3. thalamus sends signals to insula and parietal cortex

Question 10

where does evidence accumulation occur in the brain?

Answer 10

• firing rate increasing as evidence accumulates
• high expression of K+ channels -> K+ channels leaky so hyperpolarises membrane potential. slows depolarisation up to spike threshold. information is integrated more slowly.