scholarly journals Cue to action processing in motor cortex populations

2014 ◽  
Vol 111 (2) ◽  
pp. 441-453 ◽  
Author(s):  
Naveen G. Rao ◽  
John P. Donoghue
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Visual Target ◽  
Neuron Activity ◽  
Action Processing ◽  
Action Network ◽  
Ensemble Activity ◽  
Array Recordings ◽  
Population Decoding ◽  
Single Neuron Activity

The primary motor cortex (MI) commands motor output after kinematics are planned from goals, thought to occur in a larger premotor network. However, there is a growing body of evidence that MI is involved in processes beyond action generation, and neuronal subpopulations may perform computations related to cue-to-action processing. From multielectrode array recordings in awake behaving Macaca mulatta monkeys, our results suggest that early MI ensemble activity during goal-directed reaches is driven by target information when cues are closely linked in time to action. Single-neuron activity spanned cue presentation to movement, with the earliest responses temporally aligned to cue and the later responses better aligned to arm movements. Population decoding revealed that MI's coding of cue direction evolved temporally, likely going from cue to action generation. We confirmed that a portion of MI activity is related to visual target processing by showing changes in MI activity related to the extinguishing of a continuously pursued visual target. These findings support a view that MI is an integral part of a cue-to-action network for immediate responses to environmental stimuli.

scholarly journals Dopamine control of pyramidal neuron activity in the primary motor cortex via D2 receptors

2014 ◽  
Vol 8 ◽  
Author(s):  
Clément Vitrac ◽  
Sophie Péron ◽  
Isabelle Frappé ◽  
Pierre-Olivier Fernagut ◽  
Mohamed Jaber ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Pyramidal Neuron ◽  
Primary Motor Cortex ◽  
D2 Receptors ◽  
Neuron Activity

Partial Reconstruction of Muscle Activity From a Pruned Network of Diverse Motor Cortex Neurons

2007 ◽  
Vol 97 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Marc H. Schieber ◽  
Gil Rivlis
Keyword(s):  
Motor Cortex ◽  
Motor Neurons ◽  
Primary Motor Cortex ◽  
Activity Patterns ◽  
Neuron Activity ◽  
Emg Activity ◽  
Weighted Sum ◽  
Partial Reconstruction ◽  
Average Similarity ◽  
Upper Motor Neurons

Primary motor cortex (M1) neurons traditionally have been viewed as “upper motor neurons” that directly drive spinal motoneuron pools, particularly during finger movements. We used spike-triggered averages (SpikeTAs) of electromyographic (EMG) activity to select M1 neurons whose spikes signaled the arrival of input in motoneuron pools, and examined the degree of similarity between the activity patterns of these M1 neurons and their target muscles during 12 individuated finger and wrist movements. Neuron–EMG similarity generally was low. Similarity was unrelated to the strength of the SpikeTA effect, to whether the effect was pure versus synchrony, or to the number of muscles influenced by the neuron. Nevertheless, the sum of M1 neuron activity patterns, each weighted by the sign and strength of its SpikeTA effect, could be more similar to the EMG than the average similarity of individual neurons. Significant correlations between the weighted sum of M1 neuron activity patterns and EMG were obtained in six of 17 muscles, but showed R2 values ranging from only 0.26 to 0.42. These observations suggest that additional factors—including inputs from sources other than M1 and nonlinear summation of inputs to motoneuron pools—also contributed substantially to EMG activity patterns. Furthermore, although each of these M1 neurons produced SpikeTA effects with a significant peak or trough 6–16 ms after the triggering spike, shifting the weighted sum of neuron activity to lead the EMG by 40–60 ms increased their similarity, suggesting that the influence of M1 neurons that produce SpikeTA effects includes substantial synaptic integration that in part may reach the motoneuron pools over less-direct pathways.

Skill Representation in the Primary Motor Cortex After Long-Term Practice

2007 ◽  
Vol 97 (2) ◽  
pp. 1819-1832 ◽  
Author(s):  
Yoshiya Matsuzaka ◽  
Nathalie Picard ◽  
Peter L. Strick
Keyword(s):  
Motor Cortex ◽  
Motor Skills ◽  
Primary Motor Cortex ◽  
Functional Organization ◽  
Response Times ◽  
Internal Representation ◽  
Neuron Activity ◽  
Movement Sequences ◽  
A Site

The acquisition of motor skills can lead to profound changes in the functional organization of the primary motor cortex (M1). For example, performance of movement sequences after prolonged practice is associated with an expansion of the effector representation in M1. Paradoxically, there is little evidence that the activity of M1 neurons reflects acquired skills, especially sequences of movements. We examined the activity of M1 neurons during skilled movement sequences in macaques trained to successively hit targets on a monitor. The targets appeared either pseudorandomly (Random mode) or in one of two repeating sequences (Repeating mode). With practice, response times for repeating sequences substantially declined and the monkeys performed the task predictively. Highly trained animals retained the acquired skill after long gaps in practice. After >2 yr of training, 40% of M1 neurons were differentially active during the two task modes. Variations in movement kinematics did not fully explain the task-dependent modulation of neuron activity. Differentially active neurons were more strongly influenced by task mode than by kinematics. Our results suggest that practice sculpts the response properties of M1 neurons. M1 may be a site of storage for the internal representation of skilled sequential movements.

Quantification of Motor Cortex Activity and Full-Body Biomechanics During Unconstrained Locomotion

2005 ◽  
Vol 94 (4) ◽  
pp. 2959-2969 ◽  
Author(s):  
Boris I. Prilutsky ◽  
Mikhail G. Sirota ◽  
Robert J. Gregor ◽  
Irina N. Beloozerova
Keyword(s):  
Motor Cortex ◽  
Principal Component ◽  
Neuron Activity ◽  
Neural Decoding ◽  
Neural Encoding ◽  
Motor Cortex Neuron ◽  
Freely Behaving ◽  
Kinematics And Kinetics ◽  
Ensemble Activity ◽  
Full Body

Recent progress in the understanding of motor cortex function has been achieved primarily by simultaneously recording motor cortex neuron activity and the movement kinematics of the corresponding limb. We have expanded this approach by combining high-quality cortical single-unit activity recordings with synchronized recordings of full-body kinematics and kinetics in the freely behaving cat. The method is illustrated by selected results obtained from two cats tested while walking on a flat surface. Using this method, the activity of 43 pyramidal tract neurons (PTNs) was recorded, averaged over 10 bins of a locomotion cycle, and compared with full-body mechanics by means of principal component and multivariate linear regression analyses. Patterns of 24 PTNs (56%) and 219 biomechanical variables (73%) were classified into just four groups of inter-correlated variables that accounted for 91% of the total variance, indicating that many of the recorded variables had similar patterns. The ensemble activity of different groups of two to eight PTNs accurately predicted the 10-bin patterns of all biomechanical variables (neural decoding) and vice versa; different small groups of mechanical variables accurately predicted the 10-bin pattern of each PTN (neural encoding). We conclude that comparison of motor cortex activity with full-body biomechanics may be a useful tool in further elucidating the function of the motor cortex.

Location of Primary Motor Cortex Function in Cerebral Migration Disorder

1998 ◽  
Vol 38 (5) ◽  
pp. 769
Author(s):  
Ho Kyu Lee ◽  
Jin Suh Kim ◽  
Youn Mee Hwang ◽  
Myung Joon Lee ◽  
Soo Mee Lim ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Migration Disorder
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