Neuromodulation (HD-tDCS) in OCD

Funding: Wellcome trust- Department of Biotechnology India Alliance Intermediate fellowship award

Overall Goals:

Error monitoring and response inhibition (EM/RI), a critical cognitive function, is deficient in OCD and this might form the basis of symptoms. The enhancement of EM/RI could potentially result in clinical improvement. Converging evidence suggests the role of cortico-striato-thalamo-cortical (CSTC) circuits in the neurobiology of OCD including the cognitive deficits. This project proposal aims to examine the neurobiological effects of high-definition transcranial direct current stimulation (HD-tDCS) on the pre-supplementary motor area(Pre-SMA),a pivotal cortical region which regulates the striatal functions, using a targeted circuitry specific approach to enhance EM/RI, in patients with OCD having persistent symptoms despite being on adequate treatment with selective serotonin reuptake inhibitors(SSRI). This would be examined through comprehensive assessment of neurohemodynamic changes (functional MRI) and electrophysiological changes(error related negativity) pertaining to EM/RI coupled with the assessment of in-vivo neurochemical alterations (Magnetic resonance spectroscopy for NAA and glutamate) prospectively in pre-SMA before and after HD-tDCS sessions using a randomised sham-controlled design. In addition, the translational implications of modulation of cognitive function would be examined by assessing the clinical improvement with HD-TDCS.