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lect fin fall 2020

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ackman678
2020-12-14 10:18:11 -05:00
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motor2.md
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<figure><img src="figs/Neuroscience5e-Fig-16.01-0_copy_c8e6e7d.jpg" height="400px"><figcaption>Neuroscience 5e Fig. 16.1</figcaption></figure>
<div style="font-size:0.5em;">
<!-- date: -->
</div>
Note:
@@ -140,11 +143,15 @@ Reticular formation neurons functions
: cardiovascular (regulate output of nucleus ambiguous) and respiratory control (ventrolateral medulla)
: sensory motor reflexes
: coordination of eye movements
: regulation of sleep and wakefulness
: regulation of sleep and wakefulness
: coordination of limb and trunk movments
: netlike, difficult to recognize distinct neuronal clusters
: does not have a uniform function as thought classically
* rostral portions (mesencephalic and pontine) of reticular formation modulate forebrain activity (Moruzzi and Magoun EEG Clin. Neurophys 1949)
* cholinergic neurons (superior cerebellar peduncle) and noradrenergic neurons (locus coeruleus) and serotonergic neurons (raphe nuclei)
* "reticular activating system"
* caudal portions involved in premotor coordination of lower somatic and visceral motor neuron pools
feedforward postural control. stabilization during ongoing movements.
@@ -163,6 +170,10 @@ feedforward postural control. stabilization during ongoing movements.
Note:
* rostral portions (gold, mesencephalic and pontine) of reticular formation modulate forebrain activity (Moruzzi and Magoun EEG Clin. Neurophys 1949)
* cholinergic neurons (superior cerebellar peduncle) and noradrenergic neurons (locus coeruleus) and serotonergic neurons (raphe nuclei)
* "reticular activating system"
* caudal portions (red) involved in premotor coordination of lower somatic and visceral motor neuron pools
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@@ -275,8 +286,6 @@ Somatotopic representation across S1 and M1
Wilder Penfield 1940s
Link not working (shockwave director needed)
[http://www.pbs.org/wgbh/aso/tryit/brain/probe.html](http://www.pbs.org/wgbh/aso/tryit/brain/probe.html)
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@@ -325,6 +334,13 @@ most corticobulbar inputs (except lower face and tongue) terminate bilaterally.
maps: muscle, movement sequences, intention?
H. Kuypers experiments
: rhesus monkey
: test function of direct vs indirect pathways from motor cortex
: transect spinal cord at medulla, leaving indirect path to spinal cord via brainstem reticular formation
: stand walk run climb intact with proximal and axial muscles, but precise distal limb usage with hands impaired (e.g. can't pick up food objects). Independent use of fingers doesn't return
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## The corticospinal and corticobulbar tracts
@@ -335,7 +351,7 @@ Note:
Corticobulbar is yellow, corticospinal in red. Note that most corticospinal axons cross the midline in the caudal medulla. Corticobulbar is for facial muscles.
internal capsue to cerebral peduncle at base of midbrain to scatter among pontine fibers and basal pontine gray matter then coalesce at ventral surface medulla to form medullary pyramids
internal capsule to cerebral peduncle at base of midbrain to scatter among pontine fibers and basal pontine gray matter then coalesce at ventral surface medulla to form medullary pyramids
*corticobulbar axons terminate primaryly on local circuit neurons rather than brainstem motor neurons*
@@ -416,7 +432,7 @@ right shows the response of a thumb muscle by a fixed latency to the single spik
Note:
*stimualtion that more roughly corresponds to volitional movemetns (hundreds of ms to sec), Graziano 2005.* With these stimus, movements are sequentiall distrubted across mutliple joints and purposeful.
*stimualtion that more roughly corresponds to volitional movements (hundreds of ms to sec), Graziano 2005.* With these stimus, movements are sequentiall distrubted across mutliple joints and purposeful.
Coordinated movements of hand and mouth after stimulation near the middle of the precentral gyrus towards head (**like for eating**).
@@ -428,7 +444,7 @@ Blue crosses are start positions, curved black lines are final positions are red
## Directional tuning of an upper motor neuron in the primary motor cortex
<figure><figcaption class="big">Monkey trained to move joystick in response to light</figcaption><img src="figs/Neuroscience5e-Fig-17.08-1R_0f3b75c.jpg" height="400px"><figcaption>Neuroscience 5e Fig. 17.8</figcaption></figure>
<figure><figcaption class="big">Monkey trained to move joystick in response to light</figcaption><img src="figs/Neuroscience5e-Fig-17.08-1R_0f3b75c.jpg" height="400px"><figcaption>Neuroscience 5e Fig. 17.8, adapted from Georgeopoulos et al, 1986</figcaption></figure>
Note:
@@ -439,13 +455,15 @@ Note:
<figure>
<figcaption class="big">Activity of a single neuron recorded in motor cortex
is dependent on the direction of the future movement
</figcaption><img src="figs/Neuroscience5e-Fig-17.08-2R_8f25ffd.jpg" height="400px"><figcaption>Neuroscience 5e Fig. 17.8</figcaption></figure>
is dependent on the direction of the future movement.
Red line indicates movement onset, blac
</figcaption><img src="figs/Neuroscience5e-Fig-17.08-2R_8f25ffd.jpg" height="400px"><figcaption>Neuroscience 5e Fig. 17.8, adapted from Georgeopoulos et al, 1986<</figcaption></figure>
Note:
Notice that the neuron is broadly tuned, even with this colored shading.
raster plots, black dashes are individal spikes from one recorded neuron, 5 trials in each direction depicted
Notice that the neuron is broadly tuned to a wide range of angles
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