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CORDIS

A new type of spike: Homoclinic spike generation in cells and networks

Project description

Neural dynamics and induction of epileptic activity

Any model of brain function takes into consideration the variability of neuronal spike generation or firing. Computational research has demonstrated differences between spike generators, showing that they can be classified into a few dynamical types with distinct computational properties. In particular, homoclinic spike generators specifically react with high sensitivity to inputs during the neuronal refractory period. Supported by evidence for homoclinic spiking in the rodent brain, the EU-funded ANewSpike project explores the intriguing hypothesis that such spike generators provide a unifying framework for the induction of epileptic activity by a wide range of physiological triggers, from temperature to energy deprivation. The current study adds a new dimension to the understanding of neural dynamics, including homoclinic spiking as an integral part of brain dynamics.

Objective

Action potentials are not all equal. Despite shared biophysical principles and even similar action-potential shape, neurons with different spike generators can encode vastly different aspects of a stimulus and result in radically different behaviors of the embedding network. Differences between spike generators may be hard to discern because the information content of a spike train is not obvious to the naked eye. This is where computational analysis comes into play: theoretical research has shown that spike generation can be classified into a few dynamical types with qualitatively distinct computational properties. Among these, so-called homoclinic spikes – unlike the other commonly considered types – have been largely ignored. Yet, homoclinic spike generators are special because only they react with high sensitivity to inputs during the refractory period. Indeed, it is directly after a spike when homoclinic spikers “listen” best.
As we recently demonstrated, this unique property has computationally exciting consequences: it can provoke a dramatic increase in network synchronization in response to minimal changes in physiological parameters, without requiring alterations in synaptic strength or connectivity. Supported by in-vitro evidence for homoclinic spiking in the rodent brain, ANewSpike explores the intriguing hypothesis that this “forgotten“ spike generator provides a unifying framework for the induction of epileptic activity by a wide range of physiological trigger parameters, from temperature to energy deprivation. Using a theory-experiment approach, we explore (i) the prevalence of homoclinic spiking in the brain, (ii) its ability to promote the transmission of high frequencies, and (iii) its ability to boost network synchronization. Our multi-scale study aims to add a novel dimension to our understanding of neural dynamics at the cellular and network level by revealing homoclinic spiking as an integral part of brain dynamics in both health and pathology.

Host institution

HUMBOLDT-UNIVERSITAET ZU BERLIN
Net EU contribution
€ 2 000 000,00
Address
UNTER DEN LINDEN 6
10117 Berlin
Germany

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Region
Berlin Berlin Berlin
Activity type
Higher or Secondary Education Establishments
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Total cost
€ 2 000 000,00

Beneficiaries (1)