Peter Berki1,2, Andras Vidosits1, Diego Lopez-Pigozzi1, Zsolt Kohus1, Daniel Schlingloff1,2, Tamas F. Freund1 and Attila I. Gulyas1
1: Institute of Experimental Medicine - Hungarian Academy of Sciences, Laboratory of Cerebral Cortex Research; Budapest (HU)
2: Semmelweis University - János Szentágothai Doctoral School, Functional Neurosciences Program; Budapest (HU)
Introduction: Inhibitory neurons (IN) have a crucial role in shaping network dynamics of the hippocampal formation. INs are diverse in many features, like dendritic geometry, distribution of inputs and variations in ion channels, assigning each type a specific integrative property.
Aims: We wanted to systematically measure the spatial and temporal integrative properties of different IN classes. So far, studies addressing this question activated the same input (i.e.: pathway, subset of axons or synapse) repeatedly. Therefore the possible effects of short-term plasticity contaminated the characterization of temporal properties. Furthermore, spatial and temporal interactions among different inputs is another important element of integration.
Method: Here we present an approach that allows us to stimulate a neuron through temporally and spatially precise combinations of many inputs by using optogenetics combined with a digital micro-mirror device (DMD).
• Can we evoke synaptically driven responses in neurons that are mimicking the physiological inputs from the network?
• Can we measure the transmission properties of many input pathways at the same time (rise / decay / amplitude / STP)?
• Can we measure the spatial and temporal interaction of multiple synaptically driven inputs or membrane currents?
• Are there any differences among the integrative properties of different IN subtypes?
• Independent, synaptically driven responses (indirect stimulation) or membrane currents (direct stimulation) can be persistently and precisely evoked.
• Optically evoked synaptic responses show the probabilistic property of transmission.
• Individual inputs might show distinct STP properties and frequency dependent transmission.
• By examining the interaction of multiple inputs, we concluded that different types can show different integrative properties, e.g. preferred integration time window.
Doctoral School: Semmelweis University – János Szentágothai Doctoral School
Program: Functional Neurosciences
Supervisor: Attila Gulyas
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