from neurons to psychophysics

Question 1

Describe the relationship between stimulus amplitude, graded receptor potentials, and spike frequency in sensory neurons

Answer 1

Upon sensory stimulation by sensory receptors in sense organs, this will lead to a graded receptor potential; however, based on the stimulus amplitude or intensity, the graded receptor potential will vary. such that a larger stimulus amplitude will lead to higher-graded recognition potential.

this will to. generation of an AP, depending on whether it is sufficient enough to reach the threshold and lead to a spike in frequency in sensory neurons.

Question 2

Explain psychometric functions and the methods and data used to obtain them

Answer 2

a psychometric function is a way to measure how well people detect or perceive things like sounds, lights, or sensations. It shows how people’s responses change depending on the strength of the stimulus.

yes/no method
problem is response bias
so use two alternatives: alternative, forced-choice
(stimulus is presented in either interval 1 or 2, then you ask which one corresponded to stimulus)- cancels our response bias assuming you have enough trials

Question 3

What is the limit to stimulus amplitude?

Answer 3

the reversal potential such that a greater intensity surpassing the reversal potential won’t lead to a generation of a greater AP

Question 4

describe the relationship between sensitivity and range

Answer 4

large range covers greater range of intensities but at lower sensitivity
and vice versa

Question 5

what can physical stimuli be measured in

Answer 5

measured in watts per square metre

Question 6

what are the two basic approaches for measuring sensation and perception?

Answer 6

threshold: measures limits of intensity
scaling:ordering stimuli along a perceptual dimension

Question 7

what are the two types of perceptual threshold?

Answer 7

• Absolute threshold: weakest stimulus intensity (the point at which we can actually detect stimulus)
• Difference threshold: smallest difference between two stimuli that an
  observer can discriminate (also called difference limen, or just-noticeable difference, JND).

Question 8

what is webers law

Answer 8

jnd is a proportional, not an absolute
amount
1kg 1.5 kg can tell difference but 10 and 10.5 it gets harder to tell difference

Question 9

explain the concept of psychophysical correlation and evaluate its applicability to the study of higher perceptual and cognitive functions

Answer 9

Identify specific patterns of neural activity and
correlate with specific sensations and
perceptions

Psychophysical and neuronal thresholds compared
* A: RFs in fingertips
* B: RFs in palms
Psychophysical thresholds for
detection correspond well
to neural thresholds in
fingertips, but are higher
than neural thresholds in
palms due to smaller sensitivity in the palms so this depends on degree of sensitivity
From Vallbo (1995)

Question 10

what are the four types of tactile afferents?
which are superficial and deep

Answer 10

pacinian corpuscle, ruffini’s corpuscle, merkel’s disc, meissner corpuscle

superficial merkel and meissner

deep is pacinian and ruffini