Somatosensory 3 Flashcards
What is the dorsal column pathway also called?
Medial Lemniscal Pathway
The dorsal column pathway is responsible for
light touch and vibrations
Where are the 3 neurons located in the dorsal column pathway, starting from the lower end of the body?
- Dorsal root ganglia
- Gracile nucleus
- Ventral posterior lateral (VPL)
Where are the 3 neurons located in the dorsal column pathway, starting from the upper end of the body?
- Dorsal root ganglia
- Cuneate nucleus
- Ventral posterior lateral (VPL)
The dorsal column pathway, for the lower part of the body, starts in the ___ spinal cord
Thoracic
The dorsal column pathway, for the upper part of the body, starts in the ___ spinal cord
Cervical
In the dorsal column pathway, where does information go after it leaves the VPL?
Primary somatic sensory cortex located within the post central gyrus in the parietal lobe
What is the highest level of the cortex?
Parietal lobe
How many lobes are there in the brain?
5
temporal, parietal, occipital, frontal, insula
Where’s the gracilis located in the spinal cord?
medial T7 and below
Information goes from medial to lateral
Where’s the cuneatus located in the spinal cord?
lateral T6 and above (C1)
Located more lateral to gracilis
Once the neurons synapse in the gracile and cuneatus nucleus, what happens?
They cross over and decussate and go to the 3rd order neuron (VPL)
What is this region?
Thalamus
What is the 3 neuron pathway in the Trigenimothalamic pathway?
- Trigeminal ganglial
- Principle nucleus of trigeminal complex
- Ventral posterior medial (VPM)
Once information reaches the VPM in the Trigenimothalamic pathway, where does it go?
Post central gyrus in the parietal lobe
Does information go through the spinal cord in the trigenimothalamic pathway?
No b/c it already passed it since this pathway is for head and neck
The trigeminothalamic pathway is responsible for
light touch, proprioception and vibration
The smaller the receptive field, the ___ innervation, the ___ neurons in the area, which ___ sensitivity
More
More
Increased
Examples of highly sensitive, more innervated areas
Mouth, Hands, Face
Describe plasticity. What’s an example with fingers and what happens to the dorsal surface?
The way the brain is able to make changes/adapt
- It maximizes your ability to do things
After amputation of a finger, those areas are unresponsive to stimuli, so the dorsal surface expands into the region that’s no longer responsive so the other areas of the finger become more sensitive b/c there’s more area allotted to them
Does plasticity account for areas of overstimulation, amputation, or both?
Both
What happens in areas of overstimulation?
Stimulation increases in the areas you mostly use (for ex certain fingers) and you loos stimulation in areas that you don’t use as often
