Navigating Neural Overload: Decoding Cortical Hyperexcitability and Aberrant Visual Perceptions

Human perception relies on a delicate balance of excitatory and inhibitory (E/I) neural processes. Disruptions to this balance can lead to elevated levels of cortical hyperexcitability, destabilizing perception and resulting in perceptual distortions or hallucinations. This phenomenon underlies aberrant experience across a range of neurological and psychological disorders, such as migraine, anxiety, depression, epilepsy, psychosis, and schizophrenia, but can also occur in neurotypical individuals. Understanding hyperexcitability in the visual cortex is crucial, as it opens new possibilities for targeted interventions to alleviate symptoms in affected individuals and provides insight into the fundamental neural mechanisms of sensory processing. This project aims to utilise advanced, computer-modelled multi-channel transcranial direct-current brain stimulation (MtDCS) to selectively target early and late visual processing regions. Early and late visual processing areas play distinct roles in perception and in the visual aberrations generated and are implicated in conditions like pattern-glare—a phenomenon where high-contrast striped gratings elicit visual distortions due to latent cortical hyperexcitability. By refining stimulation techniques, this study seeks to explore the independent and most notably, combined contributions, of early and late visual regions to aberrant perceptual experiences. Additionally, it aims to investigate compensatory interactions between these networks, where one region can be 'excited' while another is simultaneously 'inhibited', which is an extremely novel methodological approach. By investigating these areas, we aim to uncover new ways to advance our understanding of sensory processing mechanisms in the brain, with the potential to alleviate symptoms in affected individuals. Key Objectives: Develop and validate multi-channel brain stimulation protocols to selectively modulate early and late visual areas and assess their role in producing specific forms of aberrant perceptions. Modern multi-channel systems, guided by realistic computer generated brain models can now facilitate these tantalising questions. Examine the role of latent cortical hyperexcitability in mediating visual pattern-glare distortions in the laboratory. Investigate compensatory dynamics between visual processing networks through simultaneous stimulation. Applications and Benefits: This research will enhance understanding of cortical hyperexcitability by clarifying how early and late visual areas mediate specific perceptual distortions. It has significant potential for developing targeted non-invasive interventions for disorders involving hyperexcitability while also offering insights for neurotypical populations. Moreover, this work advances foundational knowledge of visual system dynamics, offering transformative implications for perceptual neuroscience and treatment strategies. The innovation contained within this project dovetails neatly with the BBSRCs research and innovation priorities and development plan. MtDCS is a cutting edge technology and computer-modelled montages based on realistic brain models have only recently come to the fore, now allowing for more detailed questions to be examine. As well as furthering our knowledge of perceptual neuroscience, the present project will help inform future clinical treatment interventions where bespoke tailor-made montages for each patient could be derived building on the foundational knowledge revealed here.