Abstracts

ATTENUATED AND AUGMENTED EMOTIONAL FACE PROCESSING NETWORKS IN TEMPORAL LOBE EPILEPSY

Abstract number : 3.201
Submission category : 5. Neuro Imaging
Year : 2012
Submission ID : 15730
Source : www.aesnet.org
Presentation date : 11/30/2012 12:00:00 AM
Published date : Sep 6, 2012, 12:16 PM

Authors :
B. W. Fling, J. D. Riley, J. J. Lin

Rationale: Although deficits in social cognition and emotional processing are significant comorbidities in people with temporal lobe epilepsy (TLE), the functional underpinnings remain unclear. The amygdala is a pivotal component for processing stimuli with emotional and social significance and has been implicated in the impaired ability to evaluate emotional situations in patients with TLE. Further, an anterior-posterior gradient exists within the temporal-occipital facial processing network in which the temporal pole (TP) and superior temporal sulcus (STS) are important for integrating autobiographical and emotional information, while the fusiform gyrus (FFA), and the lateral inferior occipital lobe (OFA) are involved in the core visual analysis of faces. Given that people with TLE have impaired facial emotional recognition, we hypothesize that functional MRI signals in the emotional integration regions (TP, STS) in TLE would be reduced compared to controls, while signals in the posterior face regions (FFA, OFA) would show no group difference. We further hypothesized that a greater magnitude of signal reduction would be seen on the temporal lobe regions ipsilateral to the side of seizure onset. Methods: Functional MRI data were obtained using a standard block design to map face sensitive regions using a fear-face paradigm in 24 patients with medically intractable TLE (Left TLE = 15; Right TLE = 9; Age = 37.4 years; female: 13) and 19 healthy controls (HC, 31.8 years; female: 10). The face-responsive regions of interest were identified in each individual using the peak voxel of the activation clusters identified by the contrast "faces > places" within the amygdala, TP, STS, FFA and OFA. We used a RMANOVA to identify group differences in percent signal change for these areas. Analyses were performed according to the side of seizure onset (ipsilateral vs. contralateral). Finally, we calculated a laterality index for number of significantly activated voxels within the amygdala. Results: TLE patients demonstrated significantly decreased activation in the ipsilateral OFA (P < 0.02), and showed a trend toward decreased activation in the ipsilateral STS (P = 0.06) compared to HC. Conversely, TLE subjects activated the contralateral TP significantly more than HC (P < 0.02). No group differences were noted for activation in either the amygdala or FFA. Lastly, in patients with TLE the amygdala laterality index showed lateralized activation contralateral to the side of seizure onset (LTLE = 0.49; RTLE = -0.43). Conclusions: Cortical activity in face integration regions was both attenuated and augmented in people with TLE. We also confirm previous work showing clear hemispheric asymmetries in amygdala activation. The attenuated fMRI signals in the ipsilateral hemisphere may reflect local network disturbances within the epileptogenic zone, while the augmented fMRI signals in the contralateral hemisphere may suggest a compensatory mechanism, providing important insights into the pathophysiology of impaired emotional process in TLE. NINDS Funding: T32-NS45540 (PI: Baram) and K23-NS060993 (PI: Lin)
Neuroimaging