Dr Roi Cohen Kadosh (Department of Experimental Psychology)
Respondent: Professor Julian Savulescu
Abstract: Around 20% of the population exhibits moderate to severe numerical disabilities, and a further percentage loses its numerical competence during the lifespan as a result of stroke or degenerative diseases. In this work, we investigated the feasibility of using noninvasive stimulation to the parietal lobe during numerical learning to selectively improve numerical abilities. We used transcranial direct current stimulation (TDCS), a method that can selectively inhibit or excitate neuronal populations by modulating GABAergic (anodal stimulation) and glutamatergic (cathodal stimulation) activity. We trained subjects for 6 days with artificial numerical symbols, during which we applied concurrent TDCS to the parietal lobes. The polarity of the brain stimulation specifically enhanced or impaired the acquisition of automatic number processing and the mapping of number into space, both important indices of numerical proficiency. The improvement was still present 6 months after the training. Control tasks revealed that the effect of brain stimulation was specific to the representation of artificial numerical symbols. The specificity and longevity of TDCS on numerical abilities establishes TDCS as a realistic tool for intervention in cases of atypical numerical development or loss of numerical abilities because of stroke or degenerative illnesses.
Bio: My principal interests focus on numerical cognition and the acquisition of numerical understanding, the functions of the parietal and prefrontal cortices and their role in numerical and magnitude representation, response selection, cognitive control functions, and the neurocognitive mechanisms of synaesthesia and possible connections with cross-modal interaction and awareness. To study these cognitive functions and perceptual abilities I am using fMRI, EEG, and noninvasive brain stimulation techniques, together with behavioural methods applied to the study of neurological patients as well as typical subjects, and special populations (developmental dyscalculia, individuals with synaesthesia)