Auditory Target and Novelty Processing in Patients with Unilateral Hippocampal Sclerosis: A Current-Source Density Study

• Published in: Scientific reports Vol. 7; no. 1; pp. 1612 - 10
• Main Authors: Vilà-Balló, Adrià, François, Clément, Cucurell, David, Miró, Júlia, Falip, Mercè, Juncadella, Montserrat, Rodríguez-Fornells, Antoni
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09-05-2017; Nature Publishing Group; Nature Portfolio
• Subjects: 59/57; 631/378/2649/1310; 631/378/2649/2150; Adult; Atenció; Attention; Auditory perception; Auditory Perception - physiology; Brain research; Cognició; Cognition; Cognitive science; Electroencephalography; Environmental changes; Epilepsy; Event-related potentials; Evoked Potentials; Exploratory Behavior; Female; Hipocamp (Cervell); Hippocampus; Hippocampus (Brain); Hippocampus - pathology; Hippocampus - physiopathology; Humanities and Social Sciences; Humans; Information processing; Linguistics; Male; Morphometry; multidisciplinary; Neuroscience; Percepció auditiva; Principal components analysis; Psychology; Science; Science (multidisciplinary); Sclerosis; Synchronization; Visual evoked potentials
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-01531-8

The capacity to respond to novel events is crucial for adapting to the constantly changing environment. Here, we recorded 29-channel Event Related Brain Potentials (ERPs) during an active auditory novelty oddball paradigm and used for the first time Current Source Density-transformed Event Related Brain Potentials and associated time-frequency spectra to study target and novelty processing in a group of epileptic patients with unilateral damage of the hippocampus (N = 18) and in healthy matched control participants (N = 18). Importantly, we used Voxel-Based Morphometry to ensure that our group of patients had a focal unilateral damage restricted to the hippocampus and especially its medial part. We found a clear deficit for target processing at the behavioral level. In addition, compared to controls, our group of patients presented (i) a reduction of theta event-related synchronization (ERS) for targets and (ii) a reduction and delayed P3a source accompanied by reduced theta and low-beta ERS and alpha event-related synchronization (ERD) for novel stimuli. These results suggest that the integrity of the hippocampus might be crucial for the functioning of the complex cortico-subcortical network involved in the detection of novel and target stimuli.