PT  - JOURNAL ARTICLE
AU  - Gil Vantomme
AU  - Zita Rovó
AU  - Romain Cardis
AU  - Elidie Béard
AU  - Georgia Katsioudi
AU  - Angelo Guadagno
AU  - Virginie Perrenoud
AU  - Laura MJ Fernandez
AU  - Anita Lüthi
TI  - A thalamic reticular circuit for head direction cell tuning and spatial navigation
AID  - 10.1101/804575
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 804575
4099  - http://biorxiv.org/content/early/2019/10/15/804575.short
4100  - http://biorxiv.org/content/early/2019/10/15/804575.full
AB  - To navigate in space, an animal must reference external sensory landmarks to the spatial orientation of its body and head. Circuit and synaptic mechanisms that integrate external cues with internal head-direction (HD) signals to drive navigational behavior remain, however, poorly described. We identify an excitatory synaptic projection from the presubiculum and retrosplenial cortex to the anterodorsalmost sector of the thalamic reticular nucleus (TRN), so far classically implied in gating sensory information flow. Projections to TRN showed driver characteristics and involved AMPA/NMDA-type glutamate receptors that initiated TRN cell burst discharge and feedforward inhibition of anterior thalamic nuclei, where HD-tuned cells relevant for egocentric navigation reside. Chemogenetic anterodorsal TRN inhibition broadened the tuning of thalamic HD cells and compromised egocentric search strategies in the Morris water maze. Besides sensory gating, TRN-dependent thalamic inhibition is an integral part of limbic navigational circuits to recruit HD-cell-dependent search strategies during spatial navigation.