Redundant information encoding in primary motor cortex during natural and prosthetic motor control

2011 ◽  
Vol 32 (3) ◽  
pp. 555-561 ◽  
Author(s):  
Kelvin So ◽  
Karunesh Ganguly ◽  
Jessica Jimenez ◽  
Michael C. Gastpar ◽  
Jose M. Carmena
NeuroImage ◽  
2009 ◽  
Vol 47 ◽  
pp. S173
Author(s):  
K Jerbi ◽  
H Hui ◽  
D Pantazis ◽  
J-P Lachaux ◽  
O Bertrand ◽  
...  

Author(s):  
David Burke

There is extensive machinery at cerebral and spinal levels to support voluntary movement, but spinal mechanisms are often ignored by clinicians and researchers. For movements of the upper and lower limbs, what the brain commands can be modified or even suppressed completely at spinal level. The corticospinal system is the executive pathway for movement arising largely from primary motor cortex, but movement is not initiated there, and other pathways normally contribute to movement. Greater use of these pathways can allow movement to be restored when the corticospinal system is damaged by, e.g. stroke, but there can be unwanted consequences of this ‘plasticity’. There is an extensive literature on cerebral mechanisms in the control of movement, and an equally large literature on spinal reflex function and the changes that occur during movement, and when pathology results in weakness and/or spasticity.


2010 ◽  
Vol 104 (5) ◽  
pp. 2873-2885 ◽  
Author(s):  
Suresh D. Muthukumaraswamy

Gamma oscillations in human primary motor cortex (M1) have been described in human electrocorticographic and noninvasive magnetoencephalographic (MEG)/electroencephalographic recordings, yet their functional significance within the sensorimotor system remains unknown. In a set of four MEG experiments described here a number of properties of these oscillations are elucidated. First, gamma oscillations were reliably localized by MEG in M1 and reached peak amplitude 137 ms after electromyographic onset and were not affected by whether movements were cued or self-paced. Gamma oscillations were found to be stronger for larger movements but were absent during the sustained part of isometric movements, with no finger movement or muscle shortening. During repetitive movement sequences gamma oscillations were greater for the first movement of a sequence. Finally, gamma oscillations were absent during passive shortening of the finger compared with active contractions sharing similar kinematic properties demonstrating that M1 oscillations are not simply related to somatosensory feedback. This combined pattern of results is consistent with gamma oscillations playing a role in a relatively late stage of motor control, encoding information related to limb movement rather than to muscle contraction.


Neuroscience ◽  
2012 ◽  
Vol 220 ◽  
pp. 11-18 ◽  
Author(s):  
W.P. Teo ◽  
J.P. Rodrigues ◽  
F.L. Mastaglia ◽  
G.W. Thickbroom

Author(s):  
Nicole Eichert ◽  
Daniel Papp ◽  
Rogier B. Mars ◽  
Kate E. Watkins

AbstractThe representations of the articulators involved in human speech production are organized somatotopically in primary motor cortex. The neural representation of the larynx, however, remains debated. Both a dorsal and a ventral larynx representation have been previously described. It is unknown, however, whether both representations are located in primary motor cortex. Here, we mapped the motor representations of the human larynx using fMRI and characterized the cortical microstructure underlying the activated regions. We isolated brain activity related to laryngeal activity during vocalization while controlling for breathing. We also mapped the articulators (the lips and tongue) and the hand area. We found two separate activations during vocalization – a dorsal and a ventral larynx representation. Structural and quantitative neuroimaging revealed that myelin content and cortical thickness underlying the dorsal, but not the ventral larynx representation, are similar to those of other primary motor representations. This finding confirms that the dorsal larynx representation is located in primary motor cortex and that the ventral one is not. We further speculate that the location of the ventral larynx representation is in premotor cortex, as seen in other primates. It remains unclear, however, whether and how these two representations differentially contribute to laryngeal motor control.


2018 ◽  
Author(s):  
James C. Dooley ◽  
Mark S. Blumberg

ABSTRACTBefore primary motor cortex (M1) develops its motor functions, it functions like a somatosensory area. Here, by recording from neurons in the forelimb representation of M1 in postnatal day (P) 8-12 rats, we demonstrate a rapid shift in its sensory responses. At P8-10, M1 neurons respond overwhelmingly to feedback from sleep-related twitches of the forelimb, but the same neurons do not respond to wake-related movements. By P12, M1 neurons suddenly respond to wake movements, a transition that results from opening the sensory gate in the external cuneate nucleus. Also at P12, few M1 neurons respond to twitches, but the full complement of twitch-related feedback observed at P8 can be unmasked through local disinhibition. Finally, through P12, M1 sensory responses originate in the deep thalamorecipient layers, not primary somatosensory cortex. These findings demonstrate that M1 initially establishes a sensory framework upon which its later-emerging role in motor control is built.


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