BIO

Clara Arrate is a second-year student pursuing a degree in Behavioral Neuroscience at Florida State. As a UROP student, she assisted with literature reviews and data analysis in an effort to examine the effects of Alpha-frequency Transcranial Alternating Current Stimulation (tACS) on dynamic brain states and the ability to sustain attention in the face of distraction. Clara is planning on further exploring her career paths and is considering working in either cognitive and behavioral neuroscience research or pursuing a psychology-related degree in the field of healthcare.

Alpha-frequency Transcranial Alternating Current Stimulation (tACS) Modulates Dynamic Brain States and Facilitates Sustained Attention

Abstract

A rapidly evolving neuromodulation methodology, transcranial alternating current stimulation (tACS), allows for interventions of human cognition, but its mechanisms of action remain unclear. Here, we use data-driven machine learning and Hidden Markov modeling of functional magnetic resonance imaging (fMRI) time series to examine the effect of alpha-frequency (8-12 Hz) tACS on the dynamics of key intrinsic connectivity networks (ICNs) during a sustained attention task. We confirmed improvement of task performance, particularly in the high- (vs. low-) load condition (p < .05), in the Active (vs. Sham) group (n/n = 12/15). Dynamic network analysis revealed 3 brain states, each characterized by their own functional connectivity and regional activation. Importantly, during the high-load condition, the Active (vs. Sham) group exhibited stronger stability of the state that reflected increased activity in the executive control and salience network, which corresponded with the improved performance. Together, these results suggest that tACS improves sustained attention by optimizing dynamic network interactions. Given the role of alpha oscillations in sensory gating and inhibitory modulation, these findings highlight possible sensory-based, bottom-up mechanisms in regulating the brain's functional organization and cognitive performance.

Keywords: Neuroscience, Cognitive Neuroscience, Attention, ADHD