Improved anti-saccade performance in major depression following repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Rachel Yep¹ (rachel.yep@sri.utoronto.ca), Christopher B. Pople^1,2, Donald C. Brien³, Brian C. Coe³, Douglas P. Munoz³, Nir Lipsman^1,2,4, Sean M. Nestor^1,2,5, Peter Giacobbe^1,2,5, Jennifer S. Rabin^1,2,6; ¹Sunnybrook Research Institute, Toronto ON, Canada, ²Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Toronto ON, Canada, ³Queen's University, Kingston ON, Canada, ⁴Division of Neurosurgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto ON, Canada, ⁵Department of Psychiatry, Sunnybrook Health Sciences Centre, University of Toronto, Toronto ON, Canada, ⁶Division of Neurology, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto ON, Canada

Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) is an effective treatment for refractory major depressive disorder (MDD). However, the mechanisms by which mood symptoms improve with rTMS remain unclear. One possibility is that rTMS enhances cognitive control by modulating the central executive network. To test this hypothesis, we used a well-characterized eye-tracking task: the interleaved pro/anti-saccade task (IPAST). On pro-saccade trials, participants look at a peripheral stimulus, yielding a measure of processing speed. On anti-saccade trials, participants suppress the reflex to look at the stimulus and instead look away, yielding a measure of cognitive control. 29 patients with MDD (mean age=44.9 years, 48% female) completed the IPAST before and after 4 weeks of rTMS. 19 non-depressed control participants (mean age=38.9 years, 58% female) completed the task at corresponding time points. Mixed ANOVAs assessed between- and within-group differences in pro- and anti-saccade reaction time (SRT). Pro-saccade SRT did not differ between groups (F(1,46)=0.20, p=0.66) or over time (F(1,46)=0.64, p=0.43), nor was there a group-by-time interaction. However, anti-saccade SRT was significantly longer in individuals with MDD compared to controls (F(1,46)=5.98, p=0.02), and decreased significantly across participants over time (F(1,46)=11.58, p=0.001). The group-by-time interaction approached significance (F(1,46)=2.36, p=0.13), with ANTI SRT decreasing over time to a greater degree in individuals with MDD compared to controls. These findings suggest a selective improvement in cognitive control following rTMS of the DLPFC in patients with MDD. Future work will examine differences between patients who respond to rTMS versus those who do not.

Topic Area: EXECUTIVE PROCESSES: Monitoring & inhibitory control