The information content of physiological and epileptic brain activity

Authors

  • Andrew J. Trevelyan,

    1. Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
    Search for more papers by this author
  • Willy Bruns,

    1. Howard Hughes Medical Institute and Center for Neural Circuits and Behavior and Neurobiology Section, Division of Biology, University of California San Diego, La Jolla, CA 92093-0634, USA
    Search for more papers by this author
  • Edward O. Mann,

    1. Department of Physiology, Anatomy and Genetics, Oxford University, Oxford OX1 3PT, UK
    Search for more papers by this author
  • Valerie Crepel,

    1. Inserm Unite 901, Université de la Mediterranee, UMR S901 Aix-Marseille, and Institut de Neurobiologie de la Mediterranee, Marseille 13009, France
    Search for more papers by this author
  • Massimo Scanziani

    1. Howard Hughes Medical Institute and Center for Neural Circuits and Behavior and Neurobiology Section, Division of Biology, University of California San Diego, La Jolla, CA 92093-0634, USA
    Search for more papers by this author

  • The report was presented at the symposium Why do some brains seize? Molecular, cellular and network mechanisms, which took place at the Epilepsy Research UK Expert International Workshop, Oxford, UK on 15–16 March 2012.

A. J. Trevelyan: Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK. Email: andrew.trevelyan@newcastle.ac.uk

Abstract

Abstract  Cerebral cortex is a highly sophisticated computing machine, feeding on information provided by the senses, which is integrated with other, internally generated patterns of neural activity, to trigger behavioural outputs. Bit by bit, we are coming to understand how this may occur, but still, the nature of the ‘cortical code’ remains one of the greatest challenges in science. As with other great scientific challenges of the past, fresh insights have come from a coalescence of different experimental and theoretical approaches. These theoretical considerations are typically reserved for cortical function rather than cortical pathology. This approach, though, may also shed light on cortical dysfunction. The particular focus of this review is epilepsy; we will argue that the information capacity of different brain states provides a means of understanding, and even assessing, the impact and locality of the epileptic pathology. Epileptic discharges, on account of their all-consuming and stereotyped nature, represent instances where the information capacity of the network is massively compromised. These intense discharges also prevent normal processing in surrounding territories, but in a different way, through enhanced inhibition in these territories. Information processing is further compromised during the period of post-ictal suppression, during interictal bursts, and also at other times, through more subtle changes in synaptic function. We also comment on information processing in other more physiological brain states.

Ancillary