Differences in the conectivity between hippocampi in patients with drug resistant epilepsy of the temporal lobe a resting-state fMRI study

Abstract

Introduction: Drug-resistant temporal lobe epilepsy is used to be treated through surgical interventions which resect the epileptogenic focus which is usually found in the hippocampus and/or the amygdala. Sometime this intervention produces some episodic memory loss, for this reason the functionality of this structures must be assessed. The objective from the present research is to observe the connectivity between both hippocampi, their functionality and evaluate their implication before the surgical process. Methodology: The sample was formed by 24 patients, all of them with temporal lobe epilepsy who completed a fMRI resting-state procedure. The images obtained from the fMRI were analysed with the software SPM12. Results: We have found the existence of slight but significative differences between the connectivity of both hippocampi, with les connectivity in patients with lesions in the left hemisphere tan lesions in the right hemisphere, as well as intragroup differences. Conclusions: The differences in connectivity inside of each group, are due to the functionality of the hippocampus, since the disconnection of one hippocampus from the other could indicate a lack of functionality. The pattern of greater affection in patients lefthanded is coherent with the greater prevalence of lack in episodic memory in this group. Neuropsychological studies with memory tasks could be useful to establish the functional connectivity in resting-state as a valid index to predict the hippocampal functionality.