1 / 6

Bifurcations and multiscale cascades in cortical dynamics

Bifurcations and multiscale cascades in cortical dynamics. Michael Breakspear , Stuart Knock, UNSW, Australia Kevin Aquino, Peter Robinson, James Roberts, University of Sydney John Terry, Serafim Rodriguez, University of Bristol, UK. Cortico-cortical connectivty where

jed
Download Presentation

Bifurcations and multiscale cascades in cortical dynamics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bifurcations and multiscale cascades in cortical dynamics Michael Breakspear, Stuart Knock, UNSW, Australia Kevin Aquino, Peter Robinson, James Roberts, University of Sydney John Terry, Serafim Rodriguez, University of Bristol, UK

  2. Cortico-cortical connectivty where describes propagating cortical field potentials Jirsa & Haken (1996) PRL Corticothalamic connectivity where describes dendritic filtering of synaptic currents model Φe time (sec) Φe strongly damped Pz time (sec) EEG time (sec) Bifurcations and multiscale cascades in cortical dynamics1: Mean Field Brain Modelling Vamembrane potentials Φafield potentials Qafiring rates a=e,i cortical populations a=s specific thalamic n. a=r reticular thalamic n. Robinson et al. (2002) Phys Rev. E 65:041924.

  3. 3 Hz instability 10 Hz instability Φe (s-1) Φe (s-1) Φe (s-1) Φe (s-1) μse μse μse μse model model Cortex-reticular–specific loop Cortex-specific loop data data Bifurcations and multiscale cascades in cortical dynamics2: Unifying explanation of seizures Global mode instabilities 1. Ignore spatial derivatives ( ) & 2. explore nonlinear bifurcations by changing μse Breakspear et al. (2006) Cerebral Cortex doi:10.1093/cercor/bhj072

  4. 1. Nonlinear frequency coupling Data Model 2. Amplitude modulation Data Model Bifurcations and multiscale cascades in cortical dynamics3:Impact of global coupling on local mean fields Global corticocortical coupling Reintroduce spatial dependency in Absence seizure (3Hz spike and wave) regimen

  5. Fast timescales, x1,2 Slow timescales, x3 Burst (slow) synchrony: c~0.35 Calculate inter-scale effects as, Spike (slow+fast) synchrony: c>0.45 Nakao et al. (2001) IJCB MS Dhamala et al. (2004) PRL t …and their anti-symmetric component, scale coarse fine aMS c t Bifurcations and multiscale cascades in cortical dynamics4: Multiscale temporal effects in neural systems Hindmarsh Rose: Between systems Hindmarsh Rose: Between scales Single node: Coupled nodes: scale fine coarse

  6. 10 Hz instability Φe (s-1) Symmetric Antisymmetric μse Model Data scale coarse fine Bifurcations and multiscale cascades in cortical dynamics5: Coupling of spatiotemporal scales in cortical activity Seizures Healthy cortical Activity

More Related