scholarly journals Neuronal Correlates of Memory Formation in Motor Cortex after Adaptation to Force Field

2010 ◽  
Vol 30 (27) ◽  
pp. 9189-9198 ◽  
Author(s):  
F. Arce ◽  
I. Novick ◽  
Y. Mandelblat-Cerf ◽  
E. Vaadia
Keyword(s):  
Motor Cortex ◽  
Force Field ◽  
Memory Formation

scholarly journals On the Effectiveness of Event-related Beta tACS on Episodic Memory Formation and Motor Cortex Excitability

2016 ◽  
Author(s):  
Verena Braun ◽  
Rodika Sokoliuk ◽  
Simon Hanslmayr
Keyword(s):  
Motor Cortex ◽  
Episodic Memory ◽  
Inferior Frontal Gyrus ◽  
Memory Formation ◽  
Frequency Range ◽  
Beta Oscillations ◽  
Healthy Human ◽  
Sham Stimulation ◽  
Motor Cortex Excitability ◽  
Beta Frequency

AbstractBackgroundTranscranial alternating current stimulation (tACS) is widely used to entrain or modulate brain oscillations in order to investigate causal relationships between oscillations and cognition.ObjectiveIn a series of experiments we here addressed the question of whether event-related, transient tACS in the beta frequency range can be used to entrain beta oscillations in two different domains: episodic memory formation and motor cortex excitability.MethodsIn experiments 1 and 2, 72 healthy human participants engaged in an incidental encoding task of verbal and non-verbal material while receiving tACS to the left and right inferior frontal gyrus (IFG) at 6.8Hz, 10.7Hz, 18.5Hz, 30Hz, 48Hz and sham stimulation for 2s during stimulus presentation.In experiment 3, tACS was administered to M1 at the individual motor beta frequency of eight subjects. We investigated the relationship between the size of TMS induced MEPs and tACS phase.ResultsBeta tACS did not affect memory performance compared to sham stimulation in experiments 1 and 2. Likewise, in experiment 3, MEP size was not modulated by the tACS phase.ConclusionsOur findings suggest that event-related, transient tACS in the beta frequency range cannot be used to modulate the formation of episodic memories or motor cortex excitability. These null-results question the effectiveness of event-related tACS to entrain beta oscillations and modulate cognition.

scholarly journals Activity of the same motor cortex neurons during repeated experience with perturbed movement dynamics

2012 ◽  
Vol 107 (11) ◽  
pp. 3144-3154 ◽  
Author(s):  
Andrew G. Richardson ◽  
Tommaso Borghi ◽  
Emilio Bizzi
Keyword(s):  
Motor Cortex ◽  
Force Field ◽  
Primary Motor Cortex ◽  
Neuronal Population ◽  
Directional Tuning ◽  
Tuning Curves ◽  
Performance Improvements ◽  
Memory Traces ◽  
Movement Dynamics

Neurons in the primary motor cortex (M1) have been shown to have persistent, memory-like activity following adaptation to altered movement dynamics. However, the techniques used to study these memory traces limited recordings to only single sessions lasting no more than a few hours. Here, chronically implanted microelectrode arrays were used to study the long-term neuronal responses to repeated experience with perturbing, velocity-dependent force fields. Force-field–related neuronal activity within each session was similar to that found previously. That is, the directional tuning curves of the M1 neurons shifted in a manner appropriate to compensate for the forces. Next, the across-session behavior was examined. Long-term learning was evident in the performance improvements across multiple force-field sessions. Correlated with this change, the neuronal population had smaller within-session spike rate changes as experience with the force field increased. The smaller within-session changes were a result of persistent across-session shifts in directional tuning. The results extend the observation of memory traces of newly learned dynamics and provide further evidence for the role of M1 in early motor memory formation.

Motor cortex single-neuron and population contributions to compensation for multiple dynamic force fields

2015 ◽  
Vol 113 (2) ◽  
pp. 487-508 ◽  
Author(s):  
Touria Addou ◽  
Nedialko I. Krouchev ◽  
John F. Kalaska
Keyword(s):  
Motor Cortex ◽  
Force Field ◽  
Time Course ◽  
Primary Motor Cortex ◽  
Force Fields ◽  
Elastic Force ◽  
Pseudorandom Sequence ◽  
Sample Population ◽  
Dynamic Force ◽  
Flexion Extension

To elucidate how primary motor cortex (M1) neurons contribute to the performance of a broad range of different and even incompatible motor skills, we trained two monkeys to perform single-degree-of-freedom elbow flexion/extension movements that could be perturbed by a variety of externally generated force fields. Fields were presented in a pseudorandom sequence of trial blocks. Different computer monitor background colors signaled the nature of the force field throughout each block. There were five different force fields: null field without perturbing torque, assistive and resistive viscous fields proportional to velocity, a resistive elastic force field proportional to position and a resistive viscoelastic field that was the linear combination of the resistive viscous and elastic force fields. After the monkeys were extensively trained in the five field conditions, neural recordings were subsequently made in M1 contralateral to the trained arm. Many caudal M1 neurons altered their activity systematically across most or all of the force fields in a manner that was appropriate to contribute to the compensation for each of the fields. The net activity of the entire sample population likewise provided a predictive signal about the differences in the time course of the external forces encountered during the movements across all force conditions. The neurons showed a broad range of sensitivities to the different fields, and there was little evidence of a modular structure by which subsets of M1 neurons were preferentially activated during movements in specific fields or combinations of fields.

scholarly journals Memory Formation in the Motor Cortex Ipsilateral to a Training Hand

2007 ◽  
Vol 18 (6) ◽  
pp. 1395-1406 ◽  
Author(s):  
J Duque ◽  
R Mazzocchio ◽  
K Stefan ◽  
F Hummel ◽  
E Olivier ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Memory Formation
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