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Friday, April 19, 2019 at 2:30pm to 3:30pm
This week's guest speaker will be Dr. Qi Wang from Columbia University. He is an Assistant Professor in the Department of Biomedical Engineering, where he directs for the Raymond and Beverly Sackler Laboratory for Neural Engineering and Control.
Locus coeruleus activation enhances thalamic information transmission and perception
Abstract: The locus coeruleus (LC) is the primary source of norepinephrine (NE) in the brain. The LC-NE system modulates behavioral state and innervates thalamic relay nuclei and the thalamic reticular nucleus, which gate transmission of information about stimulus features to the neocortex through dynamic interplay. We investigated the previously unknown effects of LC activation on thalamic feature selectivity through reverse correlation analysis of single-unit recordings from different stages of the rat vibrissa pathway. LC activation increased thalamic feature selectivity, resulting in a drastic improvement in information transmission. We found this improvement was dependent on both local activation of α-adrenergic receptors and modulation of T-type calcium channels in the thalamus and was not due to LC modulation of trigeminothalamic feedforward or corticothalamic feedback inputs. LC activation reduced thalamic bursting, but this change in thalamic firing mode was not the primary cause of the improved information transmission. Tonic spikes with LC stimulation carried 3-times the information than tonic spikes without LC stimulation, indicating LC activation improved information transmission by optimizing thalamic state for tonic information transmission. Through modelling the effects of NE on the interplay between the thalamic relay and reticular nuclei, we further demonstrated that LC-NE regulation of intrathalamic circuit dynamics underlies the improved information transmission as LC-NE modulation of either relay or reticular nucleus alone cannot account for the improvement. LC regulation of intrathalamic circuit dynamics led to a reduction in membrane potential fluctuations, which in turn suppressed T-type calcium channel activity, leading to more optimal thalamic state for information transmission. LC-NE optimization of thalamic sensory processing is also critical to perception as LC activation increased the perceptual sensitivity of animals performing tactile discrimination tasks, and this improvement was blocked when NE effects in the thalamus were pharmacologically precluded. Taken together, these results suggest a new way to enhance perception and cognition through control of neuromodulatory systems.
Bio: Qi Wang received his first Ph.D. in Robotics from Harbin Institute of Technology, China, and the second Ph.D. in Electrical and Computer Engineering from McGill University, Canada, in 1998 and 2007, respectively. He received postdoctoral training in Neuroscience at Harvard University from 2006 to 2008. Prior to joining the faculty at Columbia University in January 2013, he held a research faculty position in the Department of Biomedical Engineering at the Georgia Institute of Technology and Emory University. His research interests include neural coding, state-dependent sensory processing, brain-machine interfaces, and biomedical instrumentation. He has received numerous awards including IEEE EMBS Early Career Achievement Award, Young Investigator Award from the Brain and Behavior Foundation, and the Best Paper Awards at the 14th IEEE Haptics Symposium.