Abstracts

Rationale: Psychogenic Non-Epileptic Seizure (PNES) is a functional neurological disorder subtype frequently encountered by epileptologists. While studies have investigated clinical differences between PNES and epilepsy, few neuroimaging studies have researched brain-behavior relationships in PNES. Resting-state functional connectivity analyses have identified alterations in prefrontal regions including the anterior cingulate cortex (ACC), while a volumetric analysis reported reduced dorsal ACC (dACC) gray matter volume in PNES. The aim of this ongoing functional neuroimaging study is to characterize neural activations of negative emotional processing with and without behavioral inhibition in PNES. Methods: 3 female subjects with documented PNES were recruited (mean age=39.3; right-handed (2), left (1); minor motor events (2), atonic events (1); events/month=1.66). Two subjects were off medications, while one was prescribed lamotrigine and lorazepam. Subjects participated in two separate sessions: 1. structured psychiatric interview and self-report assessments (Beck Depression Inventory-II (BDI), Spielberger Trait Anxiety Inventory (STAI), Dissociative Experience Scale (DES), Toronto Alexithymia Scale (TAS)); 2. a validated emotional-linguistic go/no-go functional magnetic resonance imaging (fMRI) paradigm.¹ Statistical parametric analyses were performed at the subject-level. Results: Subject 1 (S1) met current diagnostic criteria for panic disorder (PD) and generalized anxiety disorder (GAD); subject 2 (S2) GAD, post-traumatic stress disorder, specific and social phobia, obsessive-compulsive disorder; subject 3 (S3) GAD, PD, specific phobia. S1 and S3 reported childhood sexual abuse. See Table 1 for individual-subject self report psychometric total scores. Per subject, statistical parametric analyses for the contrast [Negative Go vs. Neutral Go] showed (Figure 1): S1 - increased left amygdala and dACC activations; S2 - increased left posterior amygdala/hippocampus and dACC activations; S3 - increased left amygdala and right dACC activations. Statistical parametric analyses for the contrast [(Negative vs. Neutral) x (NoGo vs. Go)] showed: S1 - decreased left amygdala and dACC activations; S2 - decreased left amygdala and dACC activations; S3 - decreased left amygdala and right dACC activations. All findings at the individual-subject level had an uncorrected p-value ≤ 0.05. Conclusions: Unlike healthy subjects who have previously been shown to activate the dACC and amygdala during negative emotional processing in the context of behavioral inhibition,¹ PNES subjects exhibited decreased activations in these regions. These preliminary findings suggest potential task-specific emotional processing and cognitive control deficits in PNES that warrant further investigation. Dr. Perez was funded by a NINDS R25NS065743-05S1 grant. 1. Goldstein M, Brendel G, Tuescher O, et al. Neural substrates of the interaction of emotional stimulus processing and motor inhibitory control: an emotional linguistic go/no-go fMRI study. Neuroimage 2007;36:1026-40.