Posts Tagged M1
[ARTICLE] Transcranial Direct Current Stimulation Modulates Neuronal Activity and Learning in Pilot Training – Full Text HTML
Posted by Kostas Pantremenos in tDCS/rTMS on November 11, 2016
Skill acquisition requires distributed learning both within (online) and across (offline) days to consolidate experiences into newly learned abilities. In particular, piloting an aircraft requires skills developed from extensive training and practice. Here, we tested the hypothesis that transcranial direct current stimulation (tDCS) can modulate neuronal function to improve skill learning and performance during flight simulator training of aircraft landing procedures.
Thirty-two right-handed participants consented to participate in four consecutive daily sessions of flight simulation training and received sham or anodal high-definition-tDCS to the right dorsolateral prefrontal cortex (DLPFC) or left motor cortex (M1) in a randomized, double-blind experiment. Continuous electroencephalography (EEG) and functional near infrared spectroscopy (fNIRS) were collected during flight simulation, n-back working memory, and resting-state assessments. tDCS of the right DLPFC increased midline-frontal theta-band activity in flight and n-back working memory training, confirming tDCS-related modulation of brain processes involved in executive function. This modulation corresponded to a significantly different online and offline learning rates for working memory accuracy and decreased inter-subject behavioral variability in flight and n-back tasks in the DLPFC stimulation group. Additionally, tDCS of left M1 increased parietal alpha power during flight tasks and tDCS to the right DLPFC increased midline frontal theta-band power during n-back and flight tasks.
These results demonstrate a modulation of group variance in skill acquisition through an increasing in learned skill consistency in cognitive and real-world tasks with tDCS. Further, tDCS performance improvements corresponded to changes in electrophysiological and blood-oxygenation activity of the DLPFC and motor cortices, providing a stronger link between modulated neuronal function and behavior.
Continue —> Frontiers | Transcranial Direct Current Stimulation Modulates Neuronal Activity and Learning in Pilot Training | Frontiers in Human Neuroscience
Figure 1. Experimental design. (A) Experiment timeline depicting the relative timing of each task (see Table 1 for descriptions of each task). The N-Back and Easy Landing tasks are highlighted, and the duration of tDCS is depicted in red. (B) An example of 6 trials of the N-Back task is shown. 1-back orientation and location match trials are highlighted in yellow. (C) The flight simulator, neuroimaging (EEG and FNIRS) and tDCS setup is shown with on a subject (1). Flight simulator equipment includes three-panel display, a radio panel (2), an instrument panel (3) with (from left to right) compass, altimeter, airspeed indicator, vertical speed indicator, and turn/slip indicator, a multi-panel (4) with (from left to right) autopilot settings, auto throttle switch, flaps switch, and elevator trim wheel, yoke (5), and throttle quadrant system (6). (D) Autopilot flight path for the Easy Landing task is shown in 3 dimensions, color-coded by vertical speed. Screenshots for initial descent, approach, and landing are also shown.
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[ARTICLE] Interactions between primary and secondary motor areas for recovered hand functions after stroke
Posted by Kostas Pantremenos in Paretic Hand on July 7, 2015
Abstract
Objectives
Goal oriented hand movements are the final product of complex interplay between multiple cortical regions of the frontoparietal cortex. Following stroke, recovery of function might be related to structural and functional modifications in the surviving brain networks. Strikingly, the ventral premotor cortex (PMv) plays a crucial role in the sensorimotor processing engaged in shaping finger movements and shares extensive reciprocal projections to the primary motor cortex (M1), making the PMv a promising structure involved in hand motor recovery after stroke. By instance, mapping studies in stroke animal models consistently showed that improvement in forelimb motor performance was associated with reorganization within the PMv. However, precise functional interactions between the PMv and the M1 in the process of hand motor recovery have not been investigated in stroke patients. Paired-pulse transcranial magnetic stimulation (pp-TMS) was used in order to evaluate PMv-M1 interactions in stroke patients and healthy controls. To further disentangle whether recovery-related changes are specific to PMv-M1 or apparent in all interactions between primary and secondary motor areas after stroke, connectivity between posterior parietal cortex (PPC) and M1 have been also assessed.
Methods
22 patients (aged 62.3 ± 9.8 SD) with mild to severe unilateral hand motor deficit and 20 healthy controls (aged 59.7 ± 20.9 SD) participated in the present study. Within experiment-1, PMv-M1 interactions were investigated by using neuronavigated-ppTMS in both the affected and unaffected hemisphere, considering 6 interstimulus intervals (ISI; 2, 4, 6, 8, 10 and 15 ms) between conditioning and test pulse. In experiment-2, PPC-M1 interactions were investigated targeting two PPC regions: the anterior intraparietal sulcus (aIPS) and the caudal intraparietal sulcus (cIPS).
Results
Experiment-1: A consistent difference between patients and controls, with a group by ISI interaction, has been observed for both the affected (F = 14.9, p < 0.001) as well as the unaffected (F = 5.3, p < 0.001) hemisphere. Further posthoc analysis confirmed a significant difference at 6 and 8 ms between both groups (ISI6 ms = T = 3.4, p = 0.002; ISI8 ms = T = 7.1, p < 0.001), with consistent facilitation in stroke and rather inhibition in healthy controls. Interestingly, the amount of facilitation observed at 8 ms in stroke patients was positively correlated with the level of force production of the paretic hand (R2 = 0.33, p = 0.010) assessed by the laterality-index of grip-force. Experiment-2: No group differences have been observed between aiPS-M1 and cIPS-M1 in both hemispheres.
Conclusions
The present pp-TMS approach enabled us to assess in vivo the specific contributions of individual brain areas to recovery of function after stroke. These findings demonstrate changes in interareal connectivity between the PMv and the M1 associated with recovered hand motor function. These data support a paramount role of the PMv within the process of functional reorganization and successful hand motor recovery, as suggested in previous animal work, contributing significantly to the understanding of the mechanisms underlying cortical reorganization after focal brain lesions.
TBI Rehabilitation 