Biology subjects

Breton-Provencher, V.

Publications and source records attributed to Breton-Provencher, V..

3 recordsLinked to original sources

bioRxiv2018

Active control of arousal by a locus coeruleus GABAergic circuit

Arousal and novelty responses linked to locus coeruleus noradrenergic (LC-NA) activity affect cognitive performance. However, the mechanisms that control modes of LC-NA activity remain unknown. Here, we reveal a local population of GABAergic neurons (LC-GABA) capable of modulating LC-NA activity and arousal. Monosynaptic retrograde virus tracing shows that inputs to LC-GABA and LC-NA neurons arise from similar regions, though a few regions provide differential inputs to one subtype over the other. Recordings in the LC demonstrate two modes of LC-GABA responses whereby spiking is either correlated or broadly anti-correlated with LC-NA responses, reflecting anatomically similar and functionally coincident inputs, or differential and non-coincident inputs, to LC-NA and LC-GABA neurons. Coincident inputs control the gain of phasic LC-NA mediated novelty responses, while non-coincident inputs, such as from the prefrontal cortex to LC, alter overall levels of LC-NA responses without affecting response gain. These findings demonstrate distinct modes by which an inhibitory LC circuit regulates the gain and tone of arousal in the brain.

neuroscience↗

bioRxiv2018

Bidirectional control of orienting behavior by distinct prefrontal circuits

Sensorimotor behaviors require processing of behaviorally relevant sensory cues and the ability to select appropriate responses from a vast behavioral repertoire. Top-down modulation by the prefrontal cortex (PFC) is thought to be key for both processes but the precise role of specific circuits remains unclear. We examined the sensorimotor function of anatomically distinct outputs from a subdivision of the mouse PFC, the anterior cingulate cortex (ACC). Using a visually guided two-choice behavioral paradigm with multiple cue-response mappings, we dissociated the sensory and motor response components of sensorimotor control. Projection-specific two-photon calcium imaging and optogenetic manipulations show that ACC outputs to the superior colliculus, a key midbrain structure for response selection, principally coordinate specific motor responses. Importantly, ACC outputs exert top-down control by reducing the innate response bias of the superior colliculus. In contrast, ACC outputs to the visual cortex facilitate sensory processing of visual cues. Our results ascribe motor and sensory roles to ACC projections to the superior colliculus and the visual cortex and demonstrate for the first time a circuit motif for PFC function wherein anatomically non-overlapping output pathways coordinate complementary but distinct aspects of visual sensorimotor behavior.

neuroscience↗

bioRxiv2018

Locally coordinated synaptic plasticity shapes cell-wide plasticity of visual cortex neurons in vivo

Plasticity of cortical responses involves activity-dependent changes at synapses, but the manner in which different forms of synaptic plasticity act together to create functional changes in neuronal responses remains unknown. Here we show that spike-timing induced receptive field plasticity of individual visual cortex neurons in vivo is anchored by increases in synaptic strength of identified spines, and is accompanied by a novel decrease in the strength of adjacent spines on a slower time scale. The locally coordinated potentiation and depression of spines involves prominent AMPA receptor redistribution via targeted expression of the immediate early gene Arc. Similar changes accompany recovery of eye-specific responses following monocular deprivation. These findings demonstrate that Hebbian strengthening of activated synapses and heterosynaptic weakening of adjacent synapses, in dendrites with heterogeneous synaptic inputs, co-operatively orchestrate cell-wide plasticity of functional neuronal responses.\n\nOne Sentence SummaryArc-mediated local synaptic plasticity regulates reorganization of synaptic responses on dendritic stretches to mediate functional plasticity of neuronal responses in vivo.

neuroscience↗