A 4X1 High-Definition Transcranial Direct Current Stimulation Device for Targeting Cerebral Micro Vessels and Functionality Using NIRS

The paper presents the development of 4X1 high-definition transcranial direct current stimulation (tDCS). High-Definition Transcranial Direct Current Stimulation (HD-tDCS) has been proposed as a focal, noninvasive brain stimulation technique. In this technique, cerebral micro vessel and primary motor cortex are targeted with weak intensity direct current (approximately 2 mA) through small array of electrodes placed on the scalp. The primary mechanism of this technique is based on polarity-dependent shift of neuronal membrane potentials. These polarity-dependent shifts are used to up and down-regulate cortical activity depending on weak direct current stimulation. The paper focuses on the design of the set up for HD-tDCS and conventional tDCS. The power dissipation for high-definition tDCS has also been compared with conventional tDCS. The performance of the HD-tDCS device has been analyzed and compared with a conventional anodal tDCS device in terms of regulating the cerebral micro vessels functionality, which thereby yields signals with better signal to noise ratio (SNR) using near infrared spectroscopy (NIRS). The average SNR of the NIRS device was found to be 39.1939 dB in the OFF-state. In ON-state it is 40.80 dB and 41.910 dB for conventional and high-definition tDCS respectively.