Emotional/Psychiatric Symptom Change and Amygdala Volume After Anterior Temporal Lobectomy

Introduction Patients who undergo anterior temporal lobectomy (ATL) to treat temporal lobe epilepsy (TLE) often experience worsened or de novo psychiatric symptoms. There is evidence to suggest that the pathophysiology of epilepsy and mood disorders are linked both functionally or structurally in the brain.1,2 While several studies have examined the role that changes in hippocampal volume may play in predicting post-surgical depression, the role of the amygdala in such prediction has been overlooked, despite extensive literature demonstrating its contribution to emotion processing and expression.3,4 The goal of this project was to determine if change in amygdala volume is a predictor of depression and/or anxiety in TLE patients who undergo ATL, with specific attention given to side of surgery. Methods Data was collected from 32 patients who underwent ATLs (19 right, 13 left, matched samples). Pre- and post-surgery Personality Assessment Inventory (PAI) data were collected on 14 ATL patients. The following PAI subscales were utilized in this analysis: Anxiety: PAIANX; Anxiety Related Disorder: PAIARD; Depression: PAIDEP). Volumetric analysis was performed on pre- and post-surgical T1 MRIs using Freesurfer’s longitudinal processing function. Left and right amygdala volumes, change scores, and amygdala asymmetry ratios were calculated taking into account whole brain volume. 55% of the patients were seizurefree after 1 year (RTLE= 8, LTLE= 9); 29% received an Engel Class score of 2 or 3 (RTLE= 7, LTLE= 2

Advances in Clinical Neuroimaging

A paradigm shift has occurred in Neuroscience, with most brain diseases, even those considered focal, now viewed as having repercussions throughout the whole brain. As one might suspect these brain networks effects are quite complex, so multiple neuroimaging techniques are needed to view them. Structural magnetic resonance imaging (MRI) is used to determine the health of brain tissue, particularly in the cortex. Resting-state functional connectivity (rs-fMRI) is used to identify cortical regions communicating with each other. Diffusion imaging can verify that any two regions are, indeed, anatomically connected through white mater fibers. Lastly, functional MRI can be used to define the specific cognitive information and processes the regions and networks may be communicating about. Data from all four imaging technologies can be gathered during one MRI scanning session with a minimal increase in scanning time and no increase in patient discomfort. A key goal of our laboratory has been to create individual brain maps of cognitive functions that may be negatively affected by invasive brain treatments such as thermal ablation, brain stimulation, or resective brain surgery. Neurologic disease often leads to alterations in how and where the brain stores cognitive skills and behaviors. In some cases, changes in how the brain stores information can be so complete that the regional network implementing a function (e.g., expressive language) can be entirely discordant with established theories about the brain localization of function (e.g., Broca’s, Wernicke’s in the right not the left hemisphere; see Figure 1b). An accurate map of where in the brain key cognitive functions are located can help avoid removal of intact, functional tissue, and guide access routes so the surgeon can reach and remove the pathology. Such brain maps also save the neurosurgeon time because they can more rapidly identify the location of functional areas near the diseased or pathologic tissue that needs to be removed. Pages: 44-49