Lecture 2: Cutaneous Sensation - Central pathways Flashcards
Is sensory information transmitted to the same or opposite side of the brain?
Opposite side.
Does the gracile or cuneate tract contain afferents from the lower part of the body?
Gracile tract - lower
Cuneate tract - upper
Where are the gracile nucleus and the cuneate nucleus located?
In the medulla.
Where do the second order neurons of the dorsal column pathway synapse onto third order neurons?
The thalamus.
Where do the axons of the dorsal column pathway cross to the other side of the body?
In the medulla.
What two classes of sensory information are conveyed through the dorsal column pathway?
Touch (low threshold mechanoreceptors)
And
Joint position sense (proprioceptors in muscle and joints)
Where do the axons of the spinothalamic tract cross to the other side of the body?
In the spinal cord.
Which pathways conveys information from nociceptors, thermoreceptors and pruritoceptors (itch receptors)?
The spinothalamic tract.
Where do both the dorsal column pathway and the spinothalamic tract pass through in the pons?
The medial lemniscus.
Which pathway projects only to the Ventral Posterior (VP) nucleus of the thalamus?
Dorsal column pathway.
Where does the spinothalamic tract project to in the thalamus?
The VP (ventral posterior nucleus) and the intralaminar nuclei. Therefore the spinothalamic tract also has access to cortical areas other than S1.
Which pathway is phylogenetically older?
Spinothalamic tract.
Which pathway plays a part in recognition of shape and identifying direction of movement of a stimulus?
Dorsal column pathway.
Which Brodmann areas make up the S1 cortex?
3a, 3b, 1 and 2.
Where is the posterior parietal cortex located?
Behind S1. Brodmann areas 5 and 7.
Which area of the S1 cortex has a proprioceptive function?
3a
Which area of the S1 cortex is involved in cutaneous sensation?
3b.
Where do areas 1 and 2 of S1 receive input from? And what are the sections related to?
Areas 1 and 2 receive input from area 3b. Area 1 is involved in the sensation of texture and area 2 is involved in the sensation of size and shape.
What are two features of the columns in the S1 cortex?
Each column contains neurons that have similar responses.
And there are separate columns with rapidly and slowly adapting responses.
When the S2 cortex is activated, is it unilateral or bilateral?
Bilateral as the two sides are strongly interconnected.
Where does the S2 cortex receive input from in the brain?
The thalamus and S1.
Which sensations activate the S2 cortex?
Tactile, painful and visceral sensation.
What does the posterior parietal cortex do?
Integrates somatosensory, auditory and visual information.
