Seminar by Prof. Bargas:The pathophysiological signatures of functional connectomics in the striatal microcircuit

DATE: Tuesday, November 10
TIME: 10:00 – 11:00
VENUE: D015 Meeting Room, Level D, Lab 1

SPEAKER: Professor JOSÉ BARGAS DÍAZ, Institute of Cellular Physiology, Universidad Nacional Autónoma de México

TITLE: The pathophysiological signatures of functional connectomics in the striatal microcircuit.
Abstract:
A challenge in neuroscience is to integrate cellular and systems levels, to achieve this goal it is necessary to known how neurons organize their relations at intermediate levels. As for example, a microcircuit of histological scale with a few dozen neurons. Using network theory and calcium imaging with single-neuron resolution we studied the orchestration of neuronal activity in modules of dozens of striatal cells simultaneously. We compared control and diseased striatal microcircuits in rats. Control functional connectomics revealed long tailed distributions of connections, small-world, scale-free and hierarchical network properties. These properties were lost during pathological conditions in a way that can be quantified. A decorticated striatal microcircuit disclosed that control interactions between the cortex and the striatum depended on privileged cortical connections with a set of highly connected neurons or “hubs”. These privileged connections were limited in the 6-OHDA model of Parkinson’s disease where there was a decrease in functional hubs and the ones that remained were linked to dominant and recurrent neuron pools. In the L-DOPA induced dyskinesia model the microcircuit exhibited a loss in its hierarchical structure. Both parkinsonian and dyskinetic microcircuits revealed an excess of spontaneous activity. These pathological conditions displayed distinct temporal sequences in circuit activity. These sequences appeared as particular signatures, bringing the possibility of a future quantitative and functional pathophysiology with living tissue in vitro.