scholarly journals Noise-correlation is Modulated by Reward Expectation in the Primary Motor Cortex Bilaterally During Manual and Observational Tasks in Primates

2020 ◽  
Author(s):  
Brittany Moore ◽  
Sheng Khang ◽  
Joseph Thachil Francis

AbstractReward modulation is represented in the motor cortex (M1) and could be used to implement more accurate decoding models to improve brain computer interfaces (BCIs) (Zhao et al. 2018). Analyzing trial-to-trial noise-correlations between neural units in the presence of rewarding (R) and non-rewarding (NR) stimuli adds to our understanding of cortical network dynamics. We utilized Pearson’s correlation coefficient to measure shared variability between simultaneously recorded units (32 – 112) and found significantly higher noise-correlation and positive correlation between the populations’ signal- and noise-correlation during NR trials as compared to R trials. This pattern is evident in data from two non-human primates (NHPs) during single-target center out reaching tasks, both manual and action observation versions. We conducted mean matched noise-correlation analysis in order to decouple known interactions between event triggered firing rate changes and neural correlations. Isolated reward discriminatory units demonstrated stronger correlational changes than units unresponsive to reward firing rate modulation, however the qualitative response was similar, indicating correlational changes within the network as a whole can serve as another information channel to be exploited by BCIs that track the underlying cortical state, such as reward expectation, or attentional modulation. Reward expectation and attention in return can be utilized with reinforcement learning towards autonomous BCI updating.

2020 ◽  
Vol 14 ◽  
Author(s):  
Brittany Moore ◽  
Sheng Khang ◽  
Joseph Thachil Francis

Reward modulation is represented in the motor cortex (M1) and could be used to implement more accurate decoding models to improve brain-computer interfaces (BCIs; Zhao et al., 2018). Analyzing trial-to-trial noise-correlations between neural units in the presence of rewarding (R) and non-rewarding (NR) stimuli adds to our understanding of cortical network dynamics. We utilized Pearson’s correlation coefficient to measure shared variability between simultaneously recorded units (32–112) and found significantly higher noise-correlation and positive correlation between the populations’ signal- and noise-correlation during NR trials as compared to R trials. This pattern is evident in data from two non-human primates (NHPs) during single-target center out reaching tasks, both manual and action observation versions. We conducted a mean matched noise-correlation analysis to decouple known interactions between event-triggered firing rate changes and neural correlations. Isolated reward discriminatory units demonstrated stronger correlational changes than units unresponsive to reward firing rate modulation, however, the qualitative response was similar, indicating correlational changes within the network as a whole can serve as another information channel to be exploited by BCIs that track the underlying cortical state, such as reward expectation, or attentional modulation. Reward expectation and attention in return can be utilized with reinforcement learning (RL) towards autonomous BCI updating.


2020 ◽  
Vol 238 (7-8) ◽  
pp. 1735-1744 ◽  
Author(s):  
Andreea Loredana Cretu ◽  
Kathy L. Ruddy ◽  
Alain Post ◽  
Nicole Wenderoth

2001 ◽  
Vol 85 (2) ◽  
pp. 869-885 ◽  
Author(s):  
S. N. Baker ◽  
R. Spinks ◽  
A. Jackson ◽  
R. N. Lemon

Neural synchronization in the cortex, and its potential role in information coding, has attracted much recent attention. In this study, we have recorded long spike trains (mean, 33,000 spikes) simultaneously from multiple single neurons in the primary motor cortex (M1) of two conscious macaque monkeys performing a precision grip task. The task required the monkey to use its index finger and thumb to move two spring-loaded levers into a target, hold them there for 1 s, and release for a food reward. Synchrony was analyzed using a time-resolved cross-correlation method, normalized using an estimate of the instantaneous firing rate of the cell. This was shown to be more reliable than methods using trial-averaged firing rate. A total of 375 neurons was recorded from the M1 hand area; 235 were identified as pyramidal tract neurons. Synchrony was weak [mean k′ = 1.05 ± 0.04 (SD)] but widespread among pairs of M1 neurons (218/1359 pairs with above-chance synchrony), including output neurons. Synchrony usually took the form of a broad central peak [average width, 18.7 ± 8.7 (SD) ms]. There were marked changes during different phases of the task. As a population, synchrony was greatest during the steady hold period in striking contrast to the averaged cell firing rate, which was maximal when the animal was moving the levers into target. However, the modulation of synchrony during task performance showed considerable variation across individual cell pairs. Two types of synchrony were identified: oscillatory (with periodic side lobes in the cross-correlation) and nonoscillatory. Their relative contributions were quantified by filtering the cross-correlations to exclude either frequencies from 18 to 37 Hz or all higher and lower frequencies. At the peak of population synchrony during the hold period, about half (51.7% in one monkey, 56.2% in the other) of the synchronization was within this oscillatory bandwidth. This study provides strong support for assemblies of neurons being synchronized during specific phases of a complex task with potentially important consequences for both information processing within M1 and for the impact of M1 commands on target motoneurons.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Jack J. Q. Zhang ◽  
Kenneth N. K. Fong ◽  
Nandana Welage ◽  
Karen P. Y. Liu

Objective. To evaluate the concurrent and training effects of action observation (AO) and action execution with mirror visual feedback (MVF) on the activation of the mirror neuron system (MNS) and its relationship with the activation of the motor cortex in stroke individuals. Methods. A literature search using CINAHL, PubMed, PsycINFO, Medline, Web of Science, and SCOPUS to find relevant studies was performed. Results. A total of 19 articles were included. Two functional magnetic resonance imaging (fMRI) studies reported that MVF could activate the ipsilesional primary motor cortex as well as the MNS in stroke individuals, whereas two other fMRI studies found that the MNS was not activated by MVF in stroke individuals. Two clinical trials reported that long-term action execution with MVF induced a shift of activation toward the ipsilesional hemisphere. Five fMRI studies showed that AO activated the MNS, of which, three found the activation of movement-related areas. Five electroencephalography (EEG) studies demonstrated that AO or MVF enhanced mu suppression over the sensorimotor cortex. Conclusions. MVF may contribute to stroke recovery by revising the interhemispheric imbalance caused by stroke due to the activation of the MNS. AO may also promote motor relearning in stroke individuals by activating the MNS and motor cortex.


PLoS ONE ◽  
2012 ◽  
Vol 7 (6) ◽  
pp. e38754 ◽  
Author(s):  
Jean-François Lepage ◽  
Olivier Morin-Moncet ◽  
Vincent Beaulé ◽  
Louis de Beaumont ◽  
Francois Champoux ◽  
...  

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Shuqiang Cui ◽  
Decai Qiao ◽  
Xiaoli Liu

Objective Objective:Cortical parvalbumin-expressing inhibitory neurons(PV) control the activity of excitatory neurons and regulate their spike output. The present experiment is to determine the role of PV neuron in the reglution of excitability of primary motor cortex (M1) during the exercise-induced fatigue and possible molecular mechanism. Methods Methods: Male Wistar rats randomly divided into control group(C),exhaustive exercise group(E) and repeated exhaustive exercise group(RE). The gradually increasing load treadmill exercise-induced fatigue model was employed in the Group E and RE.The in vivo multi-channel recording methods was used for recording the neuronal electrophysiological activities of primary motor cortex.To observe the neuron firing rate changes during the rest state,immediately after exhausted exercise and after repeated exhaustive exercise.We also detected the expression of PV positive neurons in the primary motor cortex by the immunofluorescence method. The western blot method was used to determine the expression of calmodulin-dependent protein kinase II (CaMKII)、phosphorylated calmodulin-dependent protein kinase II( pCaMKII) and extracellular signal regulated kinase (ERK) in the primary motor cortex. Results Results:The electrophysioligical results indicated that the neuron firing rate after repeated exhausted excise the neuron firing rate significantly decreased compared with the rest state (P<0.05),but have no significantly changes as compared with exhausted excise;The expression of PV positive neurons in the group of E and RE significantly increased compared with the group C(P<0.01);The western blot results indicated that the protein expression of ERK in group REsignificantly decreased compared with group C, the pCaMKII expression of group RE decreased,but have no statistical difference. Conclusions Conclusion: After exercise-indued fatigue ,the increase of PV positive neuron maybe one reason for the excitability changes in primary motor cortex.the alteraions in the electrical signal may be participate in the regluation of exercise-induced fatigue. pCaMKII and ERK signal pathway may invloved in the molecular mechanism of exercise-induced fatigue.


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