Effects of Transcranial Magnetic Stimulation on Cognitive Control
Executive functions and cognitive control are used daily to regulate thoughts and perform actions. Various diseases and disorders can affect executive function and alter a person’s cognition. Understanding brain networks and their responses to perturbation is crucial in increasing the wellbeing of those with cognitive impairments. Behavioral testing and neuroimaging data were collected from healthy participants before and after exposure to Transcranial Magnetic Stimulation (TMS) administered to the left middle frontal gyrus (MFG, n = 16), a region implicated in cognitive control, or a sham condition administered at the vertex (top of the head, n = 12). The use of continuous theta-burst TMS (cTBS) on the left prefrontal cortex is thought to inhibit brain activity and affect behavior. We utilized an adapted version of the Navon Task, which tests flexible executive functioning, that required subjects to switch focus between the figure and ground of images during functional magnetic resonance imaging (fMRI) scanning. Through fMRI data, brain activity in specific regions of the left middle frontal gyrus was examined. There were no significant differences in brain activation in the left MFG before and after TMS. However, there were significant changes in performance of the behavioral task before and after TMS. Overall, performance decreased after TMS was applied specifically in the non-switching condition, suggesting a role of the left MFG in sustained focus to figure and ground stimuli.
Executive functions and cognitive control are used daily to regulate thoughts and perform actions. Various diseases and disorders can affect executive function and alter a person’s cognition. Understanding brain networks and their responses to perturbation is crucial in increasing the wellbeing of those with cognitive impairments. Behavioral testing and neuroimaging data were collected from healthy participants before and after exposure to Transcranial Magnetic Stimulation (TMS) administered to the left middle frontal gyrus (MFG, n = 16), a region implicated in cognitive control, or a sham condition administered at the vertex (top of the head, n = 12). The use of continuous theta-burst TMS (cTBS) on the left prefrontal cortex is thought to inhibit brain activity and affect behavior. We utilized an adapted version of the Navon Task, which tests flexible executive functioning, that required subjects to switch focus between the figure and ground of images during functional magnetic resonance imaging (fMRI) scanning. Through fMRI data, brain activity in specific regions of the left middle frontal gyrus was examined. There were no significant differences in brain activation in the left MFG before and after TMS. However, there were significant changes in performance of the behavioral task before and after TMS. Overall, performance decreased after TMS was applied specifically in the non-switching condition, suggesting a role of the left MFG in sustained focus to figure and ground stimuli.