Abstracts

Testing the functional integrity of mesial temporal lobe (MTL) structures in temporal lobe epilepsy (TLE) especially in presurgical planning, needs information about physiological functions within the to-be-resected anterior MTL. The amygdala and the anterior MTL itself are known to be involved in visual processing, memory and emotional assessment. A new visual paradigm presenting scenes with animated fearful faces from commercial movies alternating with landscape scenes was investigated using functional MRI. 12 healthy subjects and 3 patients with right sided TLE were scanned using a 1.5 T MRI (blocked design, coronal EPI, voxel size 3.9x3.9x5 mm3). The scans were analysed using SPM99 (Wellcome Dept., UCL London, UK) to test for individual and group effects (p=0.05 corr). We found highly significant activations of the left and right amygdala, hippocampus and MTL cortex in individual and in group analyses. In the control subjects, there was a symmetrical activity pattern in the amygdala (left-right ratio of activated voxels 1.07). In 3 patients with right TLE, fMRI activity was strongly lateralized to the healthy MTL (left-right ratio 2.42). The new paradigm seems to be a powerful method to induce anterior MTL fMRI activity. Future measurements and clinical correlations will answer the question whether the procedure is of further clinical use (e.g. whether it predicts individual postsurgical outcome).