1|Page
NROS 418 EXAM 1 (ACTUAL 2025/2026) QUESTIONS
WITH VERIFIED CORRECT ANSWERS
What are the 4 main types of mechanoreceptors and how do they respond to
picking up an object? - (answer)-Meissner's Corpuscle
This is a rapidly adapting receptor that responds best to lateral motion.
When an object is being picked up it burst fires right away and then stops firing
after a bit and when the object is placed down it burst fires, but for a shorter
amount of time than the initial pickup.
-Merkel Disk Receptor
This is a slowly adapting receptor that responds best to edges and points.
It fires the whole time the object is in contact with the skin, much faster when it is
first picked up and then the spikes become more spaced out until the end when
they rapidly fire again as the object is being placed down.
-Ruffini Ending
This is a slowly adapting receptor that responds best to skin stretch.
This fires pretty evenly the whole time the object is in contact with the hand and
does not seem to exhibit as much burst firing as the other receptors
-Pacinian Corpuscle
This is a rapidly adapting receptor that responds best to vibration.
This burst fires four times, one for the hand grasp, one for the lift, one for the
table contact, and one for the release.
What's the difference between active and passive touch and how is that
difference seen in fMRI activity? - (answer)Active touch is when you touch
something to learn what it feels like or reach for something and pick it up and
, 2|Page
attend to it whereas passive touch is when you walk by something and your arm
happens to hit it.
How is information arising from the various mechanoreceptors in the skin
directed in SI, areas 3a and 3b? - (answer)Information from each
mechanoreceptor when entering into areas 3a and 3b aligns in sub-areas
dedicated to to specific digits, when discussing mechanoreceptors in fingers and
hands.
What is a receptive field? Using receptive field size and receptor density, explain
the somatosensory map in the cortex - S1. - (answer)A receptive field is what a
sensory neuron can detect or the physical dimension in which a cell detects a
stimulus and response.
The smaller the size of the receptive field the more discriminative the sense is in
that location because that means that there are many small receptive fields
around. And the higher the receptor density the more space that is dedicated to it
in the somatosensory cortex.
Neurons in area 1 and 2 have much larger and more complex receptive fields (RF).
How does that happen? As you ascend to higher cortical areas, this pattern of RF
increasing complexity continues. SII and posterior parietal cortex often have
bilaterally symmetrical RFs, for the two hands for example. Why would this be
useful? - (answer)It is useful for receptive fields to become more and more
complicated in order to integrate more information and to adapt to situations and
allow the sides of the body to communicate with one another so that complex
activities can be completed seamlessly, combining the smaller receptive fields of
the individual touch receptors with the motor information and then
communicating it from the left to the right side and vice versa.
NROS 418 EXAM 1 (ACTUAL 2025/2026) QUESTIONS
WITH VERIFIED CORRECT ANSWERS
What are the 4 main types of mechanoreceptors and how do they respond to
picking up an object? - (answer)-Meissner's Corpuscle
This is a rapidly adapting receptor that responds best to lateral motion.
When an object is being picked up it burst fires right away and then stops firing
after a bit and when the object is placed down it burst fires, but for a shorter
amount of time than the initial pickup.
-Merkel Disk Receptor
This is a slowly adapting receptor that responds best to edges and points.
It fires the whole time the object is in contact with the skin, much faster when it is
first picked up and then the spikes become more spaced out until the end when
they rapidly fire again as the object is being placed down.
-Ruffini Ending
This is a slowly adapting receptor that responds best to skin stretch.
This fires pretty evenly the whole time the object is in contact with the hand and
does not seem to exhibit as much burst firing as the other receptors
-Pacinian Corpuscle
This is a rapidly adapting receptor that responds best to vibration.
This burst fires four times, one for the hand grasp, one for the lift, one for the
table contact, and one for the release.
What's the difference between active and passive touch and how is that
difference seen in fMRI activity? - (answer)Active touch is when you touch
something to learn what it feels like or reach for something and pick it up and
, 2|Page
attend to it whereas passive touch is when you walk by something and your arm
happens to hit it.
How is information arising from the various mechanoreceptors in the skin
directed in SI, areas 3a and 3b? - (answer)Information from each
mechanoreceptor when entering into areas 3a and 3b aligns in sub-areas
dedicated to to specific digits, when discussing mechanoreceptors in fingers and
hands.
What is a receptive field? Using receptive field size and receptor density, explain
the somatosensory map in the cortex - S1. - (answer)A receptive field is what a
sensory neuron can detect or the physical dimension in which a cell detects a
stimulus and response.
The smaller the size of the receptive field the more discriminative the sense is in
that location because that means that there are many small receptive fields
around. And the higher the receptor density the more space that is dedicated to it
in the somatosensory cortex.
Neurons in area 1 and 2 have much larger and more complex receptive fields (RF).
How does that happen? As you ascend to higher cortical areas, this pattern of RF
increasing complexity continues. SII and posterior parietal cortex often have
bilaterally symmetrical RFs, for the two hands for example. Why would this be
useful? - (answer)It is useful for receptive fields to become more and more
complicated in order to integrate more information and to adapt to situations and
allow the sides of the body to communicate with one another so that complex
activities can be completed seamlessly, combining the smaller receptive fields of
the individual touch receptors with the motor information and then
communicating it from the left to the right side and vice versa.
