Patterns of decreased functional interactivity in patients with temporal lobe epilepsy and normal MRI 1 Cendes Ana Carolina Coan¹; Brunno Machado de Campos¹; Fernando 1Neuroimaging Laboratory, University of Campinas, Campinas, Brazil Rationale: Results Compared to controls, TLE-NL patients presented lower FI manly in the ipsilateral postcentral gyrus. In addition, we found significant alterations on the ipsilateral precuneus, posterior cingulate and in the contralateral precentral gyrus (Figure1). Functional MRI (fMRI) images show decreased connectivity in resting state (RS) networks in patients with temporal lobe epilepsy (TLE) associated with hippocampal sclerosis and this could reflect cognitive and psychiatric co-morbidities. However, there is no definitive information about abnormal functional connectivity patterns in patients with TLE and normal MRI (TLE-NL). We aimed to evaluate brain regions with relative abnormal function in patients with TLE-NL through a functional interactivity (FI) analysis. The concept of FI uses averaged FC maps to define areas more or less connected, without information about the regions to which these areas are associated. The methodology keep the straightforward results provided by seed-based methods but also expands the networks of interest, giving extensive information about connectivity patterns and avoiding a strong initial assumption Fig. 1: Two sample t-test (p<0.001, cluster with at least 10 voxels). Areas with decreased FI in TLE-NL Method and Equipment Laterality We acquired resting state fMRIs (180 dynamics, voxel size=3x3x3mm³, 40 slices, no gap, TR=2sec, TE=30msec, matrix of 80x80mm) of: 20 healthy controls and 12 TLENL patients. 2 For the the RS processing and analysis we used the UF C toolbox for Matlab with SPM8. The overall FI analysis used a cubic seed (64 voxels) placed in all possible positions that retained at least 40 voxels overlapping with the cortex. For each seed an average time series was extracted and the linear correlation was estimated for all brain voxels, generating a statistical map for each seed position. Finally, the resultant maps were averaged creating a interactivity map. The resultant maps of each individual were used to perform a second level analysis: five right-TLE patients (and the same proportion of controls) had their images flipped (left-right) aiming to lateralize the epileptogenic zone to the left side. Two sample t-test (p<0.001, cluster with at least 10 voxels) were applied to compare controls and TLE-NL. Discussion and Conclusion Number of voxels Ipsilateral 180 Ipsilateral 20 Peak T-value 6.38 Peak MNI coordinate -63,-25,22 Anatomical regions Postcentral gyrus Patients with TLE-NL have a network of areas with decreased interactivity including temporal and thalamic regions, more evident ipsilateral to the epileptogenic zone. These abnormalities may be associated with cognitive impairments or comorbidities. In addition, the similarity of these findings with functional network changes associated with inter-ictal epileptiform discharges raises the hypothesis of the influence of inter-ictal activity in the brain dysfunction of patients with TLE-NL. Transversal gyrus Superior temporal gyrus Inferior Frontal Gyrus 5.76 -9,-61,25 Temporal Pole Insula 4.94 Ipsilateral -6,-91,-11 Calcarine Inferior Occipital Gyrus 42 Fusiform Gyrus 4.91 Ipsilateral -9,-61,28 Precuneus Cingulate Gyrus 109 Posterior Cingulate 4.58 Ipsilateral -45,-67,4 Middle Occpital 5.17 Contralateral 30,-85,-23 [1] Liao et al, PloS one 2010, 5:e8525; [2 Pittau et al, Epilepsia 2012, 53:1013–1023 [3] Coan et al, Epilepsia 2014 Middle Temporal Gyrus Inferior Temporal Gyrus 44 References Acknowledgment Cerebelum Inferior Occipital Gyrus 46 Fusiform Gyrus Contralateral 42 Contralateral 15 4.63 4.36 57,-31,40 60,2,7 Table 1: Significant areas with decreased FI in TLE-NL Postcentral Gyrus Precentral Gyrus Superior Temporal Gyrus Insula CORRESPONDING AUTHOR: Brunno Machado de Campos Institute: University of Campinas - UNICAMP Street: Vital Brasil, 251 City: Campinas Country: Brazil Email: [email protected]