Presynaptic serotonin 2A receptors modulate thalamocortical plasticity and associative learning.

Alexander Barre, Coralie Berthoux, Dimitri De Bundel, Emmanuel Valjent, Joël Bockaert, Philippe Marin, Carine Bécamel

Proceedings of the National Academy of Sciences of the United States of America 2016 Mar 8

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Higher-level cognitive processes strongly depend on a complex interplay between mediodorsal thalamus nuclei and the prefrontal cortex (PFC). Alteration of thalamofrontal connectivity has been involved in cognitive deficits of schizophrenia. Prefrontal serotonin (5-HT)2A receptors play an essential role in cortical network activity, but the mechanism underlying their modulation of glutamatergic transmission and plasticity at thalamocortical synapses remains largely unexplored. Here, we show that 5-HT2A receptor activation enhances NMDA transmission and gates the induction of temporal-dependent plasticity mediated by NMDA receptors at thalamocortical synapses in acute PFC slices. Expressing 5-HT2A receptors in the mediodorsal thalamus (presynaptic site) of 5-HT2A receptor-deficient mice, but not in the PFC (postsynaptic site), using a viral gene-delivery approach, rescued the otherwise absent potentiation of NMDA transmission, induction of temporal plasticity, and deficit in associative memory. These results provide, to our knowledge, the first physiological evidence of a role of presynaptic 5-HT2A receptors located at thalamocortical synapses in the control of thalamofrontal connectivity and the associated cognitive functions.

Citation

Alexander Barre, Coralie Berthoux, Dimitri De Bundel, Emmanuel Valjent, Joël Bockaert, Philippe Marin, Carine Bécamel. Presynaptic serotonin 2A receptors modulate thalamocortical plasticity and associative learning. Proceedings of the National Academy of Sciences of the United States of America. 2016 Mar 8;113(10):E1382-91