Lecture exam 2

Question 1

Define receptor potential

Answer 1

the generation of a local electrical signal via the opening of ion channels due to energy contacting some kind of specialized receptor

Question 2

Define transduction

Answer 2

Sensory events (energy) are transformed into changes in a receptor cell’s membrane potential via opening and closing of ion channels. This receptor potential is then translated into action potentials and chemical communication at the synapse.

Question 3

Define receptive field for a sensory receptor

Answer 3

In the environment, it is the stimulus region and its features that cause a cell to alter its firing.

Question 4

List the 5 properties of receptor potentials.

Answer 4

• graded response
• sustained response
• no discrete threshold for response
• response summate
• response is local

Question 5

graded response

Answer 5

amplitudes are graded with stimulus intensity

Question 6

sustained response

Answer 6

potentials may last as long as the stimulus lasts

Question 7

no discrete threshold for response

Answer 7

tiny potentials may be evoked with the smallest possible stimulus

Question 8

response summate

Answer 8

potentials sum when two or more stimuli are presented close together

Question 9

response is local

Answer 9

potentials spread passively from the site of generation

Question 10

explain how inotropic channels function

Answer 10

ionotropic channels are those that mediate fast EPSPs and IPSPs and work via ion channels (via the binding of a neurotransmitter to a receptor on the cell membrane)

Question 11

list the four ways neuromodulators can remodel ion channels

Answer 11

• the frequency of opening of a channel
• the duration of opening of a channel
• the ionic specificity of the channel
• the # of active channels in a piece of membrane

Question 12

list the four ways stimulus intensity can be encoded in the nervous system

Answer 12

• freq of action potentials (AP)

- temporal codes

Question 13

explain frequency of action potentials (AP)

Answer 13

the more intense a stimulus, the more frequent AP are (temporal coding) but they are limited to a max of 1200 AP/sec (and some may only fire 150 AP/sec)

Question 14

explain temporal codes

Answer 14

a complex message —> pattern of pulses,

= intensity represented by the pattern of activity of many thousands of neurons acting in parallel

Question 15

explain number of receptors impacted by energy

Answer 15

multiple receptors acting in parallel indicate higher intensity

Question 16

explain range fractionation

Answer 16

different receptors are specialists in ranges/fractions of intensity (sensitivity/threshold varies)

Question 17

briefly explain the operant theory of pain behavior

Answer 17

reinforcement rewards and maintains pain behavior so that disability is maintained and normal or typical behavior is not. this is assumed to actually increase the amount of pain that is felt by the individual. however, if alternate well behaviors are reinforced and pain behavior is not, pain behavior should reduce, and more normal or typical functioning should be restored