Year: 2016
Type: article
Abstract: Sensory stimulation drives complex interactions across neural circuits as information is encoded and then transmitted from one brain region to the next. In the highly interconnected thalamocortical circuit, these complex interactions elicit repeatable neural dynamics in response to temporal patterns of stimuli that provide insight into the circuit properties that generated them. Here, using a combination of in vivo voltage-sensitive dye (VSD) imaging of cortex, single-unit recording in thalamus, and optogenetics to manipulate thalamic state in the rodent vibrissa pathway, we probed the thalamocortical circuit with simple temporal patterns of stimuli delivered either to the whiskers on the face (sensory stimulation) or to the thalamus directly via electrical or optogenetic inputs (artificial stimulation). VSD imaging of cortex in response to whisker stimulation revealed classical suppressive dynamics, while artificial stimulation of thalamus produced an additional facilitation dynamic in cortex not observed with sensory stimulation. Thalamic neurons showed enhanced bursting activity in response to artificial stimulation, suggesting that bursting dynamics may underlie the facilitation mechanism we observed in cortex. To test this experimentally, we directly depolarized the thalamus, using optogenetic modulation of the firing activity to shift from a burst to a tonic mode. In the optogenetically depolarized thalamic state, the cortical facilitation dynamic was completely abolished. Together, the results obtained here from simple probes suggest that thalamic state, and ultimately thalamic bursting, may play a key role in shaping more complex stimulus-evoked dynamics in the thalamocortical pathway. NEW & NOTEWORTHY: For the first time, we have been able to utilize optogenetic modulation of thalamic firing modes combined with optical imaging of cortex in the rat vibrissa system to directly test the role of thalamic state in shaping cortical response properties.
Source: Journal of Neurophysiology
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: bronze
Funders: National Science Foundation, Georgia Institute of Technology, Emory University, Institute for Bioengineering and Biosciences, National Institutes of Health, Directorate for Engineering, Parker H. Petit Institute for Bioengineering and Bioscience, National Institute on Drug Abuse, National Institute of Neurological Disorders and Stroke, National Center for Advancing Translational Sciences
Awards: Thalamic synchrony and the gating of information flow to cortex, From Cells to Systems and Applications: Computational Neuroscience Training at Em, In-vivo control of information flow by artificial stimulation: ephys and behavior, Thalamocortical state control of tactile sensing: Mechanisms, Models, and Behavior, G4700852728, Atlanta Clinical and Translational Science Institute (ACTSI) Renewal, Controlling thalamic state for somatosensory information flow in thalamus
OpenAlex ID: W2534304445