Speaker: Dr Christina Mo
The Florey Institute of Neuroscience and Mental Health
Melbourne
Title: Transthalamic pathways for perception
Abstract: Perceptual processing occurs between cortical areas, first primary cortex and then higher order cortices. This communication is served in part by transthalamic (cortico-thalamo-cortical) pathways, which ubiquitously parallel direct corticocortical pathways, but their functional role has largely remained unexplored.
I will present unpublished results from my Postdoc at the University of Chicago that the somatosensory transthalamic pathway in mice propagates task-relevant information for correct sensory decisions. We used the red-shifted opsin, Jaws to specifically inhibit the pathway at its synapse in higher order thalamus of mice trained to discriminate between textures presented to the whiskers. At the same time, we monitored the effects of the inhibition in neurons of the primary or secondary cortex using two-photon calcium imaging.
Inhibiting the transthalamic pathway severely impaired the ability of mice to discriminate textures, even though direct corticocortical projections were still intact. This result challenges the purely corticocentric map of perception. The optogenetic silencing did not affect whisking or latency to lick and there was no effect in laser controls. Inhibition did not reduce overall cell responsiveness to the textures in somatosensory cortices, but rather disrupted the learned selectivity of neurons to the rewarded textures.
Transthalamic pathways thus appear to deliver performance-relevant information to higher order cortex and are critical but underappreciated hierarchical pathways in perceptual decision-making.
About Neuroscience Seminars
Neuroscience seminars at the QBI play a major role in the advancement of neuroscience in the Asia-Pacific region. The primary goal of these seminars is to promote excellence in neuroscience through the exchange of ideas, establishing new collaborations and augmenting partnerships already in place.
Seminars in the QBI Auditorium are held on Wednesdays at 12-1pm, which are sometimes simulcast on Zoom (with approval from the speaker). We also occassionally hold seminars from international speakers via Zoom. The days and times of these seminars will vary depending on the time zone of the speaker. Please see each seminar listed below for details.
