Authors :
Presenting Author: Yvonne Reed, MS – Baylor College of Medicine
Madaline Mocchi, PhD – University of Iowa
Brian Metzger, PhD – Swarthmore College
Raissa Mathura, BS – Baylor College of Medicine
Bailey Pascuzzi, BS – Baylor College of Medicine
Suhruthaa Pulapaka, BS – Baylor College of Medicine
Layth Mattar, BS – Baylor College of Medicine
Andrew Watrous, PhD – Baylor College of Medicine
Eleonora Bartoli, PhD – Baylor College of Medicine
Josh Adkinson, PhD – Baylor College of Medicine
Huy Q Dang, MD – Baylor College of Medicine
Ethan Devara, BS – Baylor College of Medicine
Alica Goldman, MD, PhD – Baylor University
Vaishnav Krishnan, MD, PhD – Baylor College of Medicine
Atul Maheshwari, MD – Baylor College of Medicine
Lu Lin, MD, PhD – Baylor College of Medicine
Jay Gavvala, MD – UT Health Houston
Carl Hacker, PhD – Emory
Xiaoxu Fan, PhD – Baylor College of Medicine
Kelly Bijanki, PhD – Baylor College of Medicine
Rationale:
Mood disorders are highly comorbid with epilepsy and significantly reduce quality of life, yet mood symptoms are often underdiagnosed and difficult to monitor in this population. Identifying objective neurophysiological markers of affective state could support more personalized and responsive treatment planning. Prior work in treatment-resistant depression (TRD) has shown that a flatter aperiodic 1/f slope in the affective salience network (ASN) is associated with lower depression severity. The present study tested whether this relationship generalizes to non-TRD individuals and whether positive and negative affective scores are differentially associated with aperiodic neural activity across ASN regions.
Methods:
Seventeen adult patients (ages 18–54; 9 female/8 male) undergoing phase II stereo-EEG monitoring for medically refractory epilepsy completed two validated mood inventories: the Computerized Adaptive Test for Depression Inventory (CAT-DI) and the Positive and Negative Affect Schedule (PANAS). Resting-state electrophysiological recordings were obtained, and aperiodic slope was extracted from regions within the ASN. Pearson correlational analyses were performed between slope and mood scores with significance set at α = 0.05.
Results:
Aperiodic 1/f slope in the affective salience network showed clear, region-specific links to mood measures. In the vmPFC, a flatter slope was associated with lower depression severity (CAT-DI, p = 0.001) and with both higher positive affect (PANAS-Pos, p = 0.017) and higher negative affect (PANAS-Neg, p = 0.011). In the DPFC, slope flattening was linked only to greater depression severity (CAT-DI, p = 0.015) and showed no relationship with PANAS scores. In the insula, a flatter slope predicted higher positive affect (PANAS-Pos, p = 0.007) with no connection to depression severity or negative affect. Finally, amygdala slope was associated solely with negative affect (PANAS-Neg, p = 0.018) and not with depression or positive affect.
Conclusions:
These findings extend prior TRD-based work by demonstrating that aperiodic 1/f slope reliably tracks mood in epilepsy patients without a clinical depression diagnosis, and that different nodes of the ASN carry distinct signals. The vmPFC reflects a general affective state, DPFC indexes depression severity specifically, and insula versus amygdala are tuned to positive and negative affect, respectively. This regional specificity underscores the potential of 1/f slope as a versatile, noninvasive biomarker for both global mood and valence-specific processes in epilepsy.
Funding: Grant Number: 5R01MH127006-05, Project Title: Mapping and Modulating the Spatiotemporal dynamics of socio-affective processing