CONICET | Buscador de Institutos y Recursos Humanos

Epileptic seizures are sudden changes in neural activity that interfere with the normal functioning of the neural network, expressed through hypersynchronic discharges. One of the most widely accepted experimental models for mesial temporal lobe epilepsy (MTLE) is Kindling. Hippocampal Rapid Kindling (RK) derives from traditional Kindling, being a more practical experimental model because it renders fully klindled animals in a shorter period of time. The aim of this study is to analyze how single-unit activity (SUA) and local field potentials (LFP) would be affected during the progression of epileptogenesis.Male Wistar rats were implanted with a bipolar macroelectrode in the CA1 region of right ventral hippocampus, through which they were kindled. Additionally, eight microwires were placed in the CA1 region of right dorsal hippocampus. SUA and LFP were recorded continuously during the whole RK protocol. SUA and LFP ictal and interictal activity of dorsal right hippocampus were analyzed.We found heterogeneous changes in neuronal firing rate during electrographic seizure activity. Different patterns of neuronal activity were observed. Some neurons increase and others decrease their firing rates, while many units did not change. The seizure ending was mainly accompanied by a prominent decrease in neuronal firing activity of all registered neurons. The interictal firing rate becomes higher according as epileptogenesis progresses.These different degrees of stereotypical firing patterns during seizures might depend on whether or not neurons are actually being recruited by the propagating wave of seizure spread. The combined study of single-unit firing rate and LFP can provide new insights into the process of transition to seizure, allowing us to assess more precisely the dynamic changes involved in epileptogenesis. Future studies are needed to understand how these patterns would be involved in epileptogenic networks.