Anodal transcranial direct current stimulation with monopolar pulses improves limb use after stroke by enhancing inter-hemispheric coherence

Abstract

Post-stroke neurological deficits, such as sensorimotor impairments, are often permanent and a leading cause of disability. Stroke is also associated with changes in neuronal synchrony among different brain areas. Multiple studies demonstrated that non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS), enhances the efficacy of existing rehabilitative therapies. We hypothesized that the therapeutic effects of tDCS could be due to its influence on neuronal synchrony. To study this, we recorded local field potentials in rats treated with anodal tDCS (a-tDCS) after unilateral ischemic motor cortex lesion. To enhance the effect of a-tDCS on neuronal synchrony, we added monopolar pulses (a-tDCSmp) during a treatment. We found that ischemic lesions reduced interhemispheric coherence in the low gamma frequency range. By contrast, a-tDCSmp treatment increased interhemispheric coherence along with motor improvement in a skilled reaching task. These observations indicate that increased neuronal coherence is a likely mechanism by which tDCS improves stroke recovery. Moreover, this work adds to previous evidence that measures of brain coherence could be used as a biomarker of stroke recovery, which may help in the design of more effective tDCS protocols for stroke rehabilitation.

Data-driven analyses of motor impairments in animal models of neurological disorders

“…Sixteen male Long-Evans rats, 3 months old and weighing 300–400 g, were used in this experiment, out of which nine rats had induced lesions in the forelimb area of primary motor cortex by a focal photothrombosis method [70,71]. To induce photothrombotic lesions, the skull over the motor cortex on the side contralateral to the skilled forelimb for reaching was thinned using a fine dental burr in a rectangular shape from −1.0 to 4.0 mm (posterior–anterior) to bregma and −1.0 to 4.0 mm lateral to the midline.…”

A Neural Network Reveals Motoric Effects of Maternal Preconception Exposure to Nicotine on Rat Pup Behavior: A New Approach for Movement Disorders Diagnosis

“…In the future, the behavioral analyses described here could be combined with histological analyses ( Faraji et al, 2013 ) or with electrophysiological recordings ( Schjetnan and Luczak, 2011 ; Ponjavic-Conte et al, 2012 ; Schjetnan et al, 2019 ). Most neuronal analyses rely on using expert selected features of brain activity (e.g., spike timing, correlations, firing rate in specific time) to relate it to behavior or sensory stimuli ( Luczak et al, 2004 ; Luczak and Narayanan, 2005 ; Quiroga and Panzeri, 2009 ).…”