Granger causality relationships between local field potentials in an animal model of temporal lobe epilepsy

Abstract

An understanding of the in vivo spatial emergence of abnormal brain activity during spontaneous seizure onset is critical to future early seizure detection and closed-loop seizure prevention therapies. In this study, we use Granger causality (GC) to determine the strength and direction of relationships between local field potentials (LFPs) recorded from bilateral microelectrode arrays in an intermittent spontaneous seizure model of chronic temporal lobe epilepsy before, during, and after Racine grade partial onset generalized seizures. Our results indicate distinct patterns of directional GC relationships within the hippocampus, specifically from the CA1 subfield to the dentate gryus, prior to and during seizure onset. Our results suggest sequential and hierarchical temporal relationships between the CA1 and dentate gyrus within and across hippocampal hemispheres during seizure. Additionally, our analysis suggests a reversal in the direction of GC relationships during seizure, from an abnormal pattern to more anatomically expected pattern. This reversal correlates well with the observed behavioral transition from tonic to clonic seizure in time-locked video. These findings highlight the utility of GC to reveal dynamic directional temporal relationships between multichannel LFP recordings from multiple brain regions during unprovoked spontaneous seizures.

Photoacoustic Imaging of Epilepsy

“…Figure 4c 2 shows the Granger causality analysis for group 2 data where we see that the primary and secondary contralateral brain foci influenced each other mutually with a stronger influence of the primary focus relative to the contralateral focus. Moreover, we suggest that the primary seizure focus may influence the contralateral foci as previously suggested using optical intrinsic imaging in epilepsy (Khalilov et al 2003) and microelectrode recordings of hippocampus local field potentials (Zhou et al 2009, Cadotte et al 2010. Finally, from group 3 analyses (Fig.…”

A study of problems encountered in Granger causality analysis from a neuroscience perspective

“…Neuroscientists have applied Granger causality methods to diverse sources of data, including electroencephalography (EEG), magnetoencephalography (MEG), functional magnetic resonance imaging (fMRI), and local field potentials (LFP). These studies have investigated functional neural systems at scales of organization from the cellular level (1-3) to whole-brain network activity (4), under a range of conditions, including sensory stimuli (5-7), varying levels of consciousness (8)(9)(10), cognitive tasks (11), and pathological states (12,13). In such analyses, the time series data are interpreted to reflect neural activity from a particular source, and Granger causality is used to characterize the directionality, directness, and dynamics of influence between sources.…”

Mapping the epileptic brain with EEG dynamical connectivity: Established methods and novel approaches

“…A method based on the analysis of the residual covariance matrix of a multichannel autoregressive model was proposed in [26]. In [27] Granger causality has been used in an animal model to study information transfer between distant regions of interest, in order to assess abnormal brain activity during a spontaneous seizure onset.…”