TRANSCRANIAL DIRECT CURRENT STIMULATION
Visual hallucinations are common in psychotic disorders (30-70% prevalence) and are often associated with poorer outcome and treatment refractoriness. Dysregulation of the visual pathway, including the extrastriate visual cortex, has been implicated in the presence of VH. Our lab utilizes high definition transcranial direct current stimulation (HD-tDCS) alongside electroencephalography to target potential novel regions of the brain involved in the maintenance of visual hallucinations. Our research allows us to gain a better understanding the electrophysiology of the brain, identify causal relationships between psychotic symptoms and structures within the brain while providing a basis for novel targeted therapeutics. Impairments in the visual system can manifest themselves as visual perceptual aberrations, deficits in visual processing tasks, and visual hallucinations. Past research with functional neuroimaging techniques have identified neural correlates of visual hallucinations across multiple brain regions, including the lateral geniculate nucleus and occipital cortex. They have also supported the hypothesis suggesting that increased visual cortex activity and over-stimulation of the sensory cortex may generate visual hallucinations.
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Electroencephalography (EEG) is a painless way of recording brain activity through the placement of small sensors on the exterior of the scalp. The benefits of EEG include its high temporal resolution and ability to detect small changes in brain electrophysiology. By combining EEG with HD-tDCS, we can record the neural activity of the brain and target regions associated with psychotic symptoms through sophisticated software.
HD-tDCS is a way to modulate the brain’s electrophysiology by introducing a weak electrical current (1-2 mA) to a targeted cortical region of interest. By changing the excitability of the ROI, we can better understand how the brain functions and how psychotic symptoms manifest. Past research on HD-tDCS have shown promising results related to modulating cognitive ability and decreasing the presence of auditory hallucinations. However, little is known about its effect on visual hallucinations (VH). Our aim is to target a brain region causally associated with visual hallucinations and to analyze the effects on cognition.