Using Transcranial Direct Current Stimulation to better understand the imagery neural network

Motor imagery ability relates to the extent to which an individual can mentally represent an action without its execution. This capacity serves many purposes including the learning of motor skills, sports or dance performance, imitation, gestures and any other motor related activities. Through proper mental planning and internal representation of a particular movement or act, daily activities can be fulfilled. It is therefore important to understand how this ability functions. The aim of this master thesis is to generate better comprehension of the imagery neural network. Mirror neurons are supposed to have a role in motor imagery but there have not been any studies investigating their functional relationship, or this domain explicitly. For this purpose, 10 right-handed participants (mean age = 21.8, SD = 1.62) underwent anodal and sham transcranial direct current stimulation (tDCS) to the left inferior frontal gyrus (IFG) in a within-subjects design with ABBA counterbalancing. We hypothesised that the brain stimulation of the IFG, a mirror neuron region, would have an effect on the ability to execute mental images of hand actions evaluated by an imagery task questionnaire completed via a computer, during the tDCS sessions. Moreover, we presumed that the ability to perform right-hand imagery actions would increase as compared to left-hand imagery and sham condition. As a result, we found significantly higher imagery scores in the anodal condition. However, we did not obtain any significant interaction effect of anodal tDCS on imagery handedness for right-hand imagery. Irrespective of right and left-hand imagery, enhancement in imagery ability during anodal tDCS was nonetheless found. Possible explanations of the non-effect for imagery handedness might be the particular involvement of the IFG found in both right and left hand imagery and, the specifics of the tDCS mechanism that have not yet been uncovered.