Ch. 3 Intensity Coding in Sensory Systems

Question 1

absolute threshold

Answer 1

ads

Question 2

transduction

Answer 2

the conversion of stimulus energy into a change in membrane potential

ex: when skin is touched, message is transduced by depolarization of mechanoreceptors in skin

Question 3

Weber’s law

Answer 3

ΔI/I = constant

ΔI = JND
I = baseline intensity

Question 4

expansive function

Answer 4

exponent > 1

constant increments in stimulus intensity yield increasingly greater increments in magnitude of perception

ex: pain

Question 5

dynamic range

Answer 5

-

Question 6

receptor potential

Answer 6

current flowing through channels produces THIS change in membrane potential

AKA generator potential

Question 7

G-protein

Answer 7

a

Question 8

transduction

Answer 8

a

Question 9

11-cis retinal

Answer 9

a

Question 10

increment threshold

Answer 10

a

Question 11

encoding

Answer 11

transmitter release or action potentials

Question 12

Weber-Fechner law

Answer 12

based on ΔI/I is constant & assuming Δψ for any JND is also constant,

Δψ = (K ΔI) / I = constant

• has been shown true only under highly-restricted conditions, if it all

Question 13

compressive function

Answer 13

exponent less than 1

• systems are sensitive to small changes in weak stimuli but detect only larger changes in intense stimuli

Ex: in dark room, can see tiny light, but couldn’t see that out in the sun
Ex: vision & audition

Question 14

generator potential saturation

Answer 14

a

Question 15

second messenger

Answer 15

a

Question 16

PDE

Answer 16

a

Question 17

rhodopsin

Answer 17

a

Question 18

JND

Answer 18

just-noticeable difference

Question 19

adaptation

Answer 19

a

Question 20

Steven’s power law

Answer 20

log ψ = K log (I - Io)

so ψ = (I - Io)K

perceived magnitude of a stimulus is a function of the intensity of the stimulus I raised to some power K

Question 21

operating characteristic

Answer 21

a curve that describes the conversion of stimulus energy to a neural representation of that energy at the level of transduction & encoding

(you get it by plotting discharge frequency of spike-generating receptor against stimulus intensity)

Question 22

receptor gain

Answer 22

a

Question 23

cGMP

Answer 23

a

Question 24

enzymatic cascade

Answer 24

a

Question 25

opsin

Answer 25

a

Question 26

dark current

Answer 26

a

Question 27

sensitivity

Answer 27

a