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2016-11-14-lecture14.md
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--- ---
## Central pattern generators organize the cycle of locomotion for terrestrial mammals ## Central pattern generators organize the cycle of activity for locomotion
<figure><img src="figs/Neuroscience5e-Fig-16.15-0_312da6c.jpg" height="400px"><figcaption>Neuroscience 5e Fig. 16.15</figcaption></figure> <figure><img src="figs/Neuroscience5e-Fig-16.15-0_312da6c.jpg" height="400px"><figcaption>Neuroscience 5e Fig. 16.15</figcaption></figure>
@@ -627,14 +627,25 @@ Note:
--- ---
## Central pattern generators organize the cycle of locomotion for terrestrial mammals ## Central pattern generators organize the cycle of activity for locomotion
<div><iframe src="https://www.youtube.com/embed/wPiLLplofYw" width="420" height="315"></iframe><figcaption>Locomotion in decerebrate cat</figcaption></div> <div><iframe src="https://www.youtube.com/embed/wPiLLplofYw" width="420" height="315"></iframe><figcaption>Locomotion in decerebrate cat</figcaption></div>
Note:
S Grillner, P Zangger. On the central generation of locomotion in the low spinal cat. Experimental Brain Research, 1979
--- ---
## Central pattern generator model circuit ## Central pattern generator circuit model for swimming
<div><figcaption class="big">Lamprey</figcaption><img src="figs/Lamprey_anatomy_5f701d1.png" height="100px"><figcaption>[CC0](https://en.wikipedia.org/wiki/Lamprey)</figcaption></div>
<div><figcaption class="big">Simplified lamprey CPG model. E, excitatory; I, inhibitory; M, motor neuron
</figcaption><img src="figs/lamprey-spinal-cpg-model_a1862d9.svg" height="300px"><figcaption>J. Ackman, [CC0](https://wiki.creativecommons.org/wiki/CC0). Based on Grillner et al., *Brain Res Rev* 2008</figcaption></div>
<!--
<figure> <figure>
<figcaption>Interlimb coupling (C) with mutually inhibitory connections. <figcaption>Interlimb coupling (C) with mutually inhibitory connections.
E, extensor. F, flexor. Arrows, excitatory. Closed circles, inhibitory E, extensor. F, flexor. Arrows, excitatory. Closed circles, inhibitory
@@ -642,10 +653,20 @@ E, extensor. F, flexor. Arrows, excitatory. Closed circles, inhibitory
<img src="figs/Ting-JNeurophys1998-Fig8_7b01f81.jpg" height="400px"> <img src="figs/Ting-JNeurophys1998-Fig8_7b01f81.jpg" height="400px">
<figcaption>Ting et al., *J Neurophysiol* 1998, Fig. 8</figcaption></figure> <figcaption>Ting et al., *J Neurophysiol* 1998, Fig. 8</figcaption></figure>
-->
<!-- <figure><img src="figs/cpg-model-circuit_ce4156c.png" height="400px"><figcaption></figcaption></figure> --> <!-- <figure><img src="figs/cpg-model-circuit_ce4156c.png" height="400px"><figcaption></figcaption></figure> -->
Note: Note:
TODO: add midline, interneuron labels to svg file.
TODO: add neurons for more complete model representation
TODO: make model with flexor/extensors for vertebrate locomotion
lamprey
: ancient vertebrate
: jawless fish
: good model for cpg spinal cord circuits, well worked out
simple network of neurons that could result in alternating flexor and extensor muscle movements for locomotion and be basis of a central pattern generator circuit. simple network of neurons that could result in alternating flexor and extensor muscle movements for locomotion and be basis of a central pattern generator circuit.
spinal locomotor and brainstem respiratory CPGs (Yuste et al, Nat Rev Neurosci 2005) spinal locomotor and brainstem respiratory CPGs (Yuste et al, Nat Rev Neurosci 2005)

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2016-11-14-lecture15.md
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## Overall organization of neural structures that control movement ## Overall organization of neural structures that control movement
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Lower motor Lower motor
system system
@@ -38,7 +28,7 @@ learning
2016-03-01 09:46:39 2016-03-01 09:46:39
<div><img src="figs/Neuroscience5e-Fig-16.01-0_f1cc94b.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-16.01-0_f1cc94b.jpg" height="100px"><figcaption></figcaption></div>
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## Upper motor control ## Upper motor control
* Axons from the upper motor neurons descend to influence the local circuits in the brainstem and spinal cord that organize movements. * Axons from the upper motor neurons descend to influence the local circuits in the brainstem and spinal cord that organize movements.
* Upper motor pathways include several brainstem centers and a number of cortical areas in the frontal lobe. * Upper motor pathways include several brainstem centers and a number of cortical areas in the frontal lobe.
* Brainstem centers are especially important for postural control. * Brainstem centers are especially important for postural control.
* Motor and premotor cortex are responsible for the planning and precise control of complex sequences of voluntary movements. * Motor and premotor cortex are responsible for the planning and precise control of complex sequences of voluntary movements.
Note: Note:
@@ -65,16 +52,14 @@ Note:
## Arrangement of motor neurons and local circuit interneurons within the spinal cord ## Arrangement of motor neurons and local circuit interneurons within the spinal cord
* Medial ventral horn: motor neuron pools that innervate axial muscles and proximal limb muscles * Medial ventral horn: motor neuron pools that innervate axial muscles and proximal limb muscles
* Lateral ventral horn: motor neurons that innervate distal limb muscles. * Lateral ventral horn: motor neurons that innervate distal limb muscles.
* Local circuit interneurons lie in the intermediate zone of the spinal cord grey matter. * Local circuit interneurons lie in the intermediate zone of the spinal cord grey matter.
Neuroscience 5e Fig. 16.3 Neuroscience 5e Fig. 16.3
<div><img src="figs/neuro4e-fig-16-03-0_82eb56b.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/neuro4e-fig-16-03-0_82eb56b.jpg" height="100px"><figcaption></figcaption></div>
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@@ -84,17 +69,7 @@ Note:
## Overview of descending motor control ## Overview of descending motor control
* Body Level One <div><img src="tmp/Neuroscience5e-Fig-17.01-1R_abcbb34.jpg" height="100px"><figcaption></figcaption></div>
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
<div><img src="figs/Neuroscience5e-Fig-17.01-1R_abcbb34.jpg" height="100px"><figcaption></figcaption></div>
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@@ -107,16 +82,12 @@ somatotopic organization of the ventral horn in the cervical enlargement. Locat
## Arrangement of motor neurons and local circuit interneurons within the spinal cord ## Arrangement of motor neurons and local circuit interneurons within the spinal cord
* Medial intermediate zone local circuit neurons project to medial ventral horn motor neurons. * Medial intermediate zone local circuit neurons project to medial ventral horn motor neurons.
* Medial local circuit neurons have axons that may project to targets along the entire length of the cord, and also cross the midline to innervate contralateral side. * Medial local circuit neurons have axons that may project to targets along the entire length of the cord, and also cross the midline to innervate contralateral side.
* Lateral regions of the intermediate zone contain local neurons that synapse with motor neurons in the lateral ventral horn. * Lateral regions of the intermediate zone contain local neurons that synapse with motor neurons in the lateral ventral horn.
* Lateral circuit neurons project over a smaller area and do not cross the midline. * Lateral circuit neurons project over a smaller area and do not cross the midline.
* Allows distal regions to act independently of each other. * Allows distal regions to act independently of each other.
<div><img src="figs/neuro4e-fig-16-04-0_328e2b3.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/neuro4e-fig-16-04-0_328e2b3.jpg" height="100px"><figcaption></figcaption></div>
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## Overview of descending motor control ## Overview of descending motor control
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Neuroscience 5e Fig. 17.1 Neuroscience 5e Fig. 17.1
<div><img src="figs/Neuroscience5e-Fig-17.01-2R_08a492a.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.01-2R_08a492a.jpg" height="100px"><figcaption></figcaption></div>
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@@ -159,16 +120,12 @@ lateral ventral horn contains lower motor neurons that mediate skilled voluntary
## Medial brainstem pathways modulate theaction of motor neurons in the ventromedial area ## Medial brainstem pathways modulate theaction of motor neurons in the ventromedial area
* Vestibular nuclei: * Vestibular nuclei:
* Receive information from inner ear * Receive information from inner ear
* Project to medial regions of spinal gray matter. * Project to medial regions of spinal gray matter.
* Controls axial muscles and proximal limbs. * Controls axial muscles and proximal limbs.
* Called the vestibulospinal tract. * Called the vestibulospinal tract.
<div><img src="figs/Neuroscience5e-Fig-17.11-1R_649492a.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.11-1R_649492a.jpg" height="100px"><figcaption></figcaption></div>
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@@ -179,16 +136,12 @@ info from semicircular canals in inner ear. balance. feedback postural control
## Medial brainstem pathways modulate theaction of motor neurons in the ventromedial area ## Medial brainstem pathways modulate theaction of motor neurons in the ventromedial area
* Reticular formation: * Reticular formation:
* Receives input from higher motor cortex. * Receives input from higher motor cortex.
* Complex network of circuits located in the core of the brainstem-from midbrain to medulla. * Complex network of circuits located in the core of the brainstem-from midbrain to medulla.
* Important for posture. * Important for posture.
* Called the reticulospinal tract. * Called the reticulospinal tract.
<div><img src="figs/Neuroscience5e-Fig-17.11-2R_f9fc798.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.11-2R_f9fc798.jpg" height="100px"><figcaption></figcaption></div>
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@@ -198,17 +151,7 @@ feedforward postural control. stabilization during ongoing movements.
## Location of the reticular formation in relation to some other major landmarks ## Location of the reticular formation in relation to some other major landmarks
* Body Level One <div><img src="tmp/neuro4e-fig-17-03-0_18e53fa.jpg" height="100px"><figcaption></figcaption></div>
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
<div><img src="figs/neuro4e-fig-17-03-0_18e53fa.jpg" height="100px"><figcaption></figcaption></div>
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@@ -219,14 +162,11 @@ Note:
## Medial brainstem pathways modulate theaction of motor neurons in the ventromedial area ## Medial brainstem pathways modulate theaction of motor neurons in the ventromedial area
* Superior colliculus * Superior colliculus
* Projects to medial cell groups in the cervical cord * Projects to medial cell groups in the cervical cord
* Influences neck muscles (colliculospinal tract) * Influences neck muscles (colliculospinal tract)
* But major output of superior colliculus to spinal cord mediated by reticular formation. Axial musculature control of neck and performing orienting movements of head and eye movements. * But major output of superior colliculus to spinal cord mediated by reticular formation. Axial musculature control of neck and performing orienting movements of head and eye movements.
<div><img src="figs/neuro4e-fig-17-02-3r_5f38a2d.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/neuro4e-fig-17-02-3r_5f38a2d.jpg" height="100px"><figcaption></figcaption></div>
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@@ -236,19 +176,9 @@ tectospinal tract.
## The medial descending motor pathways ## The medial descending motor pathways
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
<div><img src="tmp/image_d920d94.pdf" height="100px"><figcaption></figcaption></div>
<div><img src="figs/image_d920d94.pdf" height="100px"><figcaption></figcaption></div>
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@@ -259,11 +189,8 @@ Note:
## Feedforward processing ## Feedforward processing
* Able to predict changes in posture, and generate an appropriate stabilizing response. * Able to predict changes in posture, and generate an appropriate stabilizing response.
* Some muscles fire in anticipation of a need for postural adjustment. * Some muscles fire in anticipation of a need for postural adjustment.
* Reticulospinal tract important for this process. If it is severed in a cat, no change in compensatory muscles occur during the process. * Reticulospinal tract important for this process. If it is severed in a cat, no change in compensatory muscles occur during the process.
* Stimulate motor cortex in the right place can induce paw lifting, and several limb muscles to fire. Inhibition of the reticulospinal tract will allow the paw to move but will prevent the movement of other limbs. * Stimulate motor cortex in the right place can induce paw lifting, and several limb muscles to fire. Inhibition of the reticulospinal tract will allow the paw to move but will prevent the movement of other limbs.
Note: Note:
@@ -274,16 +201,6 @@ Note:
## Anticipatory maintenance of body posture ## Anticipatory maintenance of body posture
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Severed reticulospinal tract will allow biceps to fire but Severed reticulospinal tract will allow biceps to fire but
will not allow the gastrocnemius to fire for posture. will not allow the gastrocnemius to fire for posture.
@@ -294,7 +211,7 @@ Neuroscience 5e Fig. 17.13
<div><img src="figs/Neuroscience5e-Fig-17.13-0_5df4fb2.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.13-0_5df4fb2.jpg" height="100px"><figcaption></figcaption></div>
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@@ -304,17 +221,7 @@ Note:
## Feedforward and feedback mechanisms of postural control ## Feedforward and feedback mechanisms of postural control
* Body Level One <div><img src="tmp/Neuroscience5e-Fig-17.14-0_52ca14e.jpg" height="100px"><figcaption></figcaption></div>
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
<div><img src="figs/Neuroscience5e-Fig-17.14-0_52ca14e.jpg" height="100px"><figcaption></figcaption></div>
Note: Note:
@@ -324,17 +231,7 @@ Note:
## Primary motor cortex and premotor cortex are in the frontal lobe ## Primary motor cortex and premotor cortex are in the frontal lobe
* Body Level One <div><img src="tmp/Neuroscience5e-Fig-17.02-0_d55a793.jpg" height="100px"><figcaption></figcaption></div>
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
<div><img src="figs/Neuroscience5e-Fig-17.02-0_d55a793.jpg" height="100px"><figcaption></figcaption></div>
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@@ -345,14 +242,11 @@ Note:
## Primary motor cortex ## Primary motor cortex
* Located in the precentral gyrus * Located in the precentral gyrus
* Receives inputs from S1, posterior parietal structures (incorporates multiple sensory modalities, used for planning). * Receives inputs from S1, posterior parietal structures (incorporates multiple sensory modalities, used for planning).
* Controls contralateral side of the body * Controls contralateral side of the body
* Topographic organization- body represented across the medial-lateral axis. More space given to areas of fine motor control. Multiple neurons can get the same muscle to fire- not located in exact same place in cortex. * Topographic organization- body represented across the medial-lateral axis. More space given to areas of fine motor control. Multiple neurons can get the same muscle to fire- not located in exact same place in cortex.
<div><img src="figs/Neuroscience5e-Fig-17.05-0_ed37921.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.05-0_ed37921.jpg" height="100px"><figcaption></figcaption></div>
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@@ -362,21 +256,11 @@ Note:
## Somatotopic representation across S1 and M1 ## Somatotopic representation across S1 and M1
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
[http://www.pbs.org/wgbh/aso/tryit/brain/probe.html](http://www.pbs.org/wgbh/aso/tryit/brain/probe.html) [http://www.pbs.org/wgbh/aso/tryit/brain/probe.html](http://www.pbs.org/wgbh/aso/tryit/brain/probe.html)
<div><img src="figs/5892_CorticalTopographybox!_ecb699f.png" height="100px"><figcaption></figcaption></div> <div><img src="tmp/5892_CorticalTopographybox!_ecb699f.png" height="100px"><figcaption></figcaption></div>
<div><img src="figs/image_d314743.png" height="100px"><figcaption></figcaption></div> <div><img src="tmp/image_d314743.png" height="100px"><figcaption></figcaption></div>
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@@ -387,18 +271,13 @@ Note:
## Motor cortex ## Motor cortex
* Located in the frontal lobe * Located in the frontal lobe
* Several adjacent and interconnected areas * Several adjacent and interconnected areas
* Primary motor cortex located in the precentral gyrus * Primary motor cortex located in the precentral gyrus
* Gets input from sensory cortex, basal ganglion and cerebellum * Gets input from sensory cortex, basal ganglion and cerebellum
* Has 6 layers, layer V is the output layer (pyramidal cells, including the large Betz cells consisting of about 5% of projection to spinal cord and concerned with fine distal movements) * Has 6 layers, layer V is the output layer (pyramidal cells, including the large Betz cells consisting of about 5% of projection to spinal cord and concerned with fine distal movements)
* Primary pathway- the corticospinal tract. Axons cross in the caudal medulla, and innervate in lateral ventral horns * Primary pathway- the corticospinal tract. Axons cross in the caudal medulla, and innervate in lateral ventral horns
<div><img src="figs/image1_3f82ace.png" height="100px"><figcaption></figcaption></div> <div><img src="tmp/image1_3f82ace.png" height="100px"><figcaption></figcaption></div>
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@@ -408,16 +287,6 @@ Note:
## Pathways from the motor cortex to the spinal cord ## Pathways from the motor cortex to the spinal cord
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Indirect pathway: postural Indirect pathway: postural
adjustments, especially for adjustments, especially for
@@ -438,7 +307,7 @@ Neuroscience 5e Fig. 17.5
<div><img src="figs/Neuroscience5e-Fig-17.15-0_f03ec91.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.15-0_f03ec91.jpg" height="100px"><figcaption></figcaption></div>
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@@ -460,21 +329,11 @@ maps: muscle, movement sequences, intention?
## The corticospinal and corticobulbar tracts ## The corticospinal and corticobulbar tracts
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Neuroscience 5e Fig. 17.4 Neuroscience 5e Fig. 17.4
<div><img src="figs/Neuroscience5e-Fig-17_42dcdad.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17_42dcdad.jpg" height="100px"><figcaption></figcaption></div>
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@@ -485,11 +344,8 @@ Corticobulbar is blue, corticospinal in red. Note that corticospinal cross the
## Facial pathway ## Facial pathway
* The primary pathway to facial muscles is the corticobulbar pathway. * The primary pathway to facial muscles is the corticobulbar pathway.
* Projection from motor cortex to motor nuclei in brainstem that control facial muscles. * Projection from motor cortex to motor nuclei in brainstem that control facial muscles.
* Some of these projections are bilateral and some only contralateral. * Some of these projections are bilateral and some only contralateral.
* Important for diagnosis where motor damage occurs after a stroke. * Important for diagnosis where motor damage occurs after a stroke.
Note: Note:
@@ -500,21 +356,11 @@ Note:
## Patterns of facial weakness and their importance for localizing neurological injury ## Patterns of facial weakness and their importance for localizing neurological injury
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Neuroscience 5e Box 17A Neuroscience 5e Box 17A
<div><img src="figs/Neuroscience5e-Box-17A-0_47bce5b.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Box-17A-0_47bce5b.jpg" height="100px"><figcaption></figcaption></div>
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@@ -525,11 +371,8 @@ Note:
## Motor fields ## Motor fields
* A stimulation of a neuron in the primary motor cortex will get multiple muscles to fire, and will inhibit other muscles. * A stimulation of a neuron in the primary motor cortex will get multiple muscles to fire, and will inhibit other muscles.
* Stimulating any of multiple upper neurons can get the same muscle to fire. * Stimulating any of multiple upper neurons can get the same muscle to fire.
* The “receptive field” of a upper motor neuron has to do with organized movements rather than specific muscle groups. * The “receptive field” of a upper motor neuron has to do with organized movements rather than specific muscle groups.
* Upper motor neurons therefore act upon more than one motor pool. * Upper motor neurons therefore act upon more than one motor pool.
Note: Note:
@@ -540,17 +383,7 @@ Note:
## What do motor maps represent? ## What do motor maps represent?
* Body Level One <div><img src="tmp/Neuroscience5e-Box-17B-0_a572ded.jpg" height="100px"><figcaption></figcaption></div>
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
<div><img src="figs/Neuroscience5e-Box-17B-0_a572ded.jpg" height="100px"><figcaption></figcaption></div>
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@@ -566,23 +399,13 @@ Shaded region in map of stimulation sites indicates cortex folded into the anter
## Activity of single upper motor neurons is correlated with muscle movements ## Activity of single upper motor neurons is correlated with muscle movements
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Neuroscience 5e Fig. 17.6 Neuroscience 5e Fig. 17.6
<div><img src="figs/Neuroscience5e-Fig-17.06-2R_34ac4f3.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.06-2R_34ac4f3.jpg" height="100px"><figcaption></figcaption></div>
<div><img src="figs/Neuroscience5e-Fig-17.06-1R_8023db6.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.06-1R_8023db6.jpg" height="100px"><figcaption></figcaption></div>
Note: Note:
@@ -604,17 +427,7 @@ right shows the response of a thumb muscle by a fixed latency to the single spik
## Purposeful movements resulting from prolonged microstimulation of the primary motor cortex ## Purposeful movements resulting from prolonged microstimulation of the primary motor cortex
* Body Level One <div><img src="tmp/Neuroscience5e-Fig-17.07-0_b1923da.jpg" height="100px"><figcaption></figcaption></div>
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
<div><img src="figs/Neuroscience5e-Fig-17.07-0_b1923da.jpg" height="100px"><figcaption></figcaption></div>
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@@ -626,19 +439,9 @@ Coordinated movements of hand towards belly as if inspecting an object. Notice
## Directional tuning of an upper motor neuron in the primary motor cortex ## Directional tuning of an upper motor neuron in the primary motor cortex
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Monkey trained to move joystick in response to light Monkey trained to move joystick in response to light
<div><img src="figs/Neuroscience5e-Fig-17.08-1R_3cd5f1a.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.08-1R_3cd5f1a.jpg" height="100px"><figcaption></figcaption></div>
Note: Note:
@@ -648,16 +451,6 @@ Note:
## Directional tuning of an upper motor neuron in the primary motor cortex ## Directional tuning of an upper motor neuron in the primary motor cortex
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Activity of a single neuron recorded in motor cortex Activity of a single neuron recorded in motor cortex
is dependent on the direction of the future movement. is dependent on the direction of the future movement.
@@ -666,7 +459,7 @@ Neuroscience 5e Fig. 17.8
<div><img src="figs/Neuroscience5e-Fig-17.08-2R_256673f.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.08-2R_256673f.jpg" height="100px"><figcaption></figcaption></div>
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@@ -677,9 +470,7 @@ Notice that the neuron is broadly tuned, even with this colored shading.
## Directional tuning of an upper motor neuron in the primary motor cortex ## Directional tuning of an upper motor neuron in the primary motor cortex
* Individual neurons are tuned too broadly to accurately predict direction of movement * Individual neurons are tuned too broadly to accurately predict direction of movement
* By comparing populations of neurons, one can calculate a direction. * By comparing populations of neurons, one can calculate a direction.
* Can use the activity of motor cortex to control robots. * Can use the activity of motor cortex to control robots.
[https://www.youtube.com/watch?v=7kctOHnrvuM](https://www.youtube.com/watch?v=7kctOHnrvuM) [https://www.youtube.com/watch?v=7kctOHnrvuM](https://www.youtube.com/watch?v=7kctOHnrvuM)
@@ -688,9 +479,9 @@ Neuroscience 5e Fig. 17.8
<div><img src="figs/Neuroscience5e-Fig-17.08-3R_4ac9fb7.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.08-3R_4ac9fb7.jpg" height="100px"><figcaption></figcaption></div>
<div><img src="figs/Neuroscience5e-Fig-17.08-4R_1e1c58e.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.08-4R_1e1c58e.jpg" height="100px"><figcaption></figcaption></div>
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@@ -700,23 +491,13 @@ Summing response from a bunch of neurons shows that the direction is better enco
## Section of pyramidal tracts in monkeys produces loss of independent digit control ## Section of pyramidal tracts in monkeys produces loss of independent digit control
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Intact (normal) Intact (normal)
After section of After section of
corticospinal fibers corticospinal fibers
<div><img src="figs/image_a144227.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/image_a144227.jpg" height="100px"><figcaption></figcaption></div>
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@@ -726,16 +507,6 @@ corticalspinal, lateral dorsal input for control of distal/fine movements of the
## Primary motor cortex and the premotor area in human ## Primary motor cortex and the premotor area in human
* Body Level One
* Body Level Two
* Body Level Three
* Body Level Four
* Body Level Five
Note: Note:
@@ -744,17 +515,7 @@ Note:
## Primary motor cortex and the premotor area in macaque monkey ## Primary motor cortex and the premotor area in macaque monkey
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@@ -777,15 +538,10 @@ the frontal eye fields organize voluntary gaze shifts. The cingulate motor areas
## The premotor cortex ## The premotor cortex
* Lies adjacent (rostral) to the primary motor cortex * Lies adjacent (rostral) to the primary motor cortex
* Makes extensive reciprocal connections with the primary motor cortex * Makes extensive reciprocal connections with the primary motor cortex
* Projects directly to spinal cord (30% of axons in the corticospinal tract). * Projects directly to spinal cord (30% of axons in the corticospinal tract).
* Lateral premotor cortex- has neurons that are tuned to a particular direction of movement (like primary motor cortex) but differs in that they fire earlier than neurons in the primary motor cortex. This is especially important in conditional motor tasks, that pair a movement with a visual cue. * Lateral premotor cortex- has neurons that are tuned to a particular direction of movement (like primary motor cortex) but differs in that they fire earlier than neurons in the primary motor cortex. This is especially important in conditional motor tasks, that pair a movement with a visual cue.
* During the pairing of a visual cue with a motor task, the neurons will fire before any initiation of the task. This is used for intentions. * During the pairing of a visual cue with a motor task, the neurons will fire before any initiation of the task. This is used for intentions.
* Lesions in monkey prevent vision conditioned tasks, although vision is fine and the task can be done in other ways. * Lesions in monkey prevent vision conditioned tasks, although vision is fine and the task can be done in other ways.
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@@ -796,19 +552,9 @@ thes neurons encode intention to perform a movement rather than just the movemen
## Mirror motor neuron activity in a ventral-anterior sector of the lateral premotor cortex ## Mirror motor neuron activity in a ventral-anterior sector of the lateral premotor cortex
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[https://www.youtube.com/watch?v=RuK2Y8JojN8](https://www.youtube.com/watch?v=RuK2Y8JojN8) [https://www.youtube.com/watch?v=RuK2Y8JojN8](https://www.youtube.com/watch?v=RuK2Y8JojN8)
<div><img src="figs/Neuroscience5e-Fig-17.10-1R_46b3807.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/Neuroscience5e-Fig-17.10-1R_46b3807.jpg" height="100px"><figcaption></figcaption></div>
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@@ -832,17 +578,7 @@ based on Giacomo Rizzolatti et al, 1996
## Mirror motor neuron activity in a ventral-anterior sector of the lateral premotor cortex ## Mirror motor neuron activity in a ventral-anterior sector of the lateral premotor cortex
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<div><img src="figs/Neuroscience5e-Fig-17.10-2R_cf5432f.jpg" height="100px"><figcaption></figcaption></div>
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@@ -856,17 +592,7 @@ does not respond when pliers are used to interact with food.
## Mirror motor neuron activity in a ventral-anterior sector of the lateral premotor cortex ## Mirror motor neuron activity in a ventral-anterior sector of the lateral premotor cortex
* Body Level One <div><img src="tmp/Neuroscience5e-Fig-17.10-3R_10c4215.jpg" height="100px"><figcaption></figcaption></div>
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<div><img src="figs/Neuroscience5e-Fig-17.10-3R_10c4215.jpg" height="100px"><figcaption></figcaption></div>
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@@ -893,10 +619,9 @@ http://nautil.us/blog/mirror-neurons-are-essential-but-not-in-the-way-you-think
## Premotor cortex – two-hand coordination ## Premotor cortex – two-hand coordination
* The monkey has learned the task: push the object through the hole and catch it with the other hand * The monkey has learned the task: push the object through the hole and catch it with the other hand
* With damage to premotor cortex, cannot coordinate two hands to do the task * With damage to premotor cortex, cannot coordinate two hands to do the task
<div><img src="figs/image2_08b969e.png" height="100px"><figcaption></figcaption></div> <div><img src="tmp/image2_08b969e.png" height="100px"><figcaption></figcaption></div>
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## Medial premotor cortex ## Medial premotor cortex
* Mediates the selection of movements. * Mediates the selection of movements.
* Specified by internal rather than external cues. * Specified by internal rather than external cues.
* Important for selecting movements based on memory, not in response to cues. * Important for selecting movements based on memory, not in response to cues.
* Cells will fire when just thinking about an event. * Cells will fire when just thinking about an event.
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@@ -922,16 +644,6 @@ Note:
## Planning movement sequence without moving activates supplemental motor area (medial premotor area) ## Planning movement sequence without moving activates supplemental motor area (medial premotor area)
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Mental rehearsal of finger sequence Mental rehearsal of finger sequence
Motor cortex Motor cortex
@@ -946,7 +658,7 @@ Supplementary
motor area motor area
<div><img src="figs/image1_52fff81.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/image1_52fff81.jpg" height="100px"><figcaption></figcaption></div>
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@@ -956,16 +668,6 @@ First neuroimaging data
## Activation of motor areas depend different on behavioral context ## Activation of motor areas depend different on behavioral context
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@@ -990,7 +692,7 @@ Learned
Sequence Sequence
<div><img src="figs/image2_132bba7.jpg" height="100px"><figcaption></figcaption></div> <div><img src="tmp/image2_132bba7.jpg" height="100px"><figcaption></figcaption></div>
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## Effects of damage to the cerebral cortex ## Effects of damage to the cerebral cortex
* By investigating patients with various types of brain damage we can see how the various components of motor performance may be affected. Examples: * By investigating patients with various types of brain damage we can see how the various components of motor performance may be affected. Examples:
* Lesions to primary motor cortex (e.g. from a stroke) result in loss of voluntary movements on the contralateral (opposite) side of the body. * Lesions to primary motor cortex (e.g. from a stroke) result in loss of voluntary movements on the contralateral (opposite) side of the body.
* Apraxia is the specific loss of the ability to plan and correctly perform co-ordinated motor skills, mainly as a result of damage to the supplementary motor area. Speech disorders result from damage to motor cortex. * Apraxia is the specific loss of the ability to plan and correctly perform co-ordinated motor skills, mainly as a result of damage to the supplementary motor area. Speech disorders result from damage to motor cortex.
* Patients can move muscles, and walk on command but can no longer link gestures to a coherent act, or to recognize the appropriate use of an object even though they can recognize what an object is. * Patients can move muscles, and walk on command but can no longer link gestures to a coherent act, or to recognize the appropriate use of an object even though they can recognize what an object is.
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## Damage to cortex: alien limb syndrome ## Damage to cortex: alien limb syndrome
* A disorder in which person feels unable to control movements of a body part, believes that the limb is alien, or believes that the body part has its own personality * A disorder in which person feels unable to control movements of a body part, believes that the limb is alien, or believes that the body part has its own personality
* It is typically associated with lesions in the supplementary motor area or those affecting blood flow to the anterior regions of the corpus callosum and the anterior cingulate * It is typically associated with lesions in the supplementary motor area or those affecting blood flow to the anterior regions of the corpus callosum and the anterior cingulate
* Man who simultaneously tried to strangle and save his wife from himself. * Man who simultaneously tried to strangle and save his wife from himself.
[https://www.youtube.com/watch?v=dIBBDuQrd-I](https://www.youtube.com/watch?v=dIBBDuQrd-I) [https://www.youtube.com/watch?v=dIBBDuQrd-I](https://www.youtube.com/watch?v=dIBBDuQrd-I)
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## The Babinski sign ## The Babinski sign
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[https://www.youtube.com/watch?v=ZFu7bdbnZx8](https://www.youtube.com/watch?v=ZFu7bdbnZx8) [https://www.youtube.com/watch?v=ZFu7bdbnZx8](https://www.youtube.com/watch?v=ZFu7bdbnZx8)
[https://www.youtube.com/watch?v=oI_ONptx2Ns](https://www.youtube.com/watch?v=oI_ONptx2Ns) [https://www.youtube.com/watch?v=oI_ONptx2Ns](https://www.youtube.com/watch?v=oI_ONptx2Ns)
@@ -1050,7 +737,7 @@ Neuroscience 5e Fig. 17.16
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@@ -1086,17 +773,7 @@ after several days recovery begins (not fully understood) and includes
## Signs of motor neuron lesions ## Signs of motor neuron lesions
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## Principles ## Principles
* Motor * Motor
* Output to muscles via ventral root * Output to muscles via ventral root
* Two main pathways: * Two main pathways:
* 1. Ventromedial system for balance, posture and controlling head & eye movements. Important for muscles of legs & trunk needed for walking. * 1. Ventromedial system for balance, posture and controlling head & eye movements. Important for muscles of legs & trunk needed for walking.
* 2. Dorsolateral system for controlling movements of upper limbs & extremities such as fingers and toes as well as movement of facial muscles. * 2. Dorsolateral system for controlling movements of upper limbs & extremities such as fingers and toes as well as movement of facial muscles.
* *
* Sensory * Sensory
* Input to primary somatosensory area via dorsal root * Input to primary somatosensory area via dorsal root
* Two main pathways: * Two main pathways:
* 1. Dorsal spinothalamic tract for proprioception (body awareness and position in space) and haptic feedback (sensation of fine touch and pressure)– crosses in medulla * 1. Dorsal spinothalamic tract for proprioception (body awareness and position in space) and haptic feedback (sensation of fine touch and pressure)– crosses in medulla
* 2. Ventral spinothalamic tract for nocioceptive information– crosses over in spinal cord * 2. Ventral spinothalamic tract for nocioceptive information– crosses over in spinal cord
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