Neuron
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Lateral habenula (LHb) neurons convey aversive and negative reward conditions through potent indirect inhibition of ventral tegmental area (VTA) dopaminergic neurons. Although VTA dopaminergic neurons reciprocally project to the LHb, the electrophysiological properties and the behavioral consequences associated with selective manipulations of this circuit are unknown. Here, we identify an inhibitory input to the LHb arising from a unique population of VTA neurons expressing dopaminergic markers. ⋯ Instead, stimulation produced GABA-mediated inhibitory synaptic transmission, which suppressed the firing of postsynaptic LHb neurons in brain slices and increased the spontaneous firing rate of VTA dopaminergic neurons in vivo. Furthermore, in vivo activation of this pathway produced reward-related phenotypes that were dependent on intra-LHb GABAA receptor signaling. These results suggest that noncanonical inhibitory signaling by these hybrid dopaminergic-GABAergic neurons act to suppress LHb output under rewarding conditions.
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The study of synaptic plasticity and specifically LTP and LTD is one of the most active areas of research in neuroscience. In the last 25 years we have come a long way in our understanding of the mechanisms underlying synaptic plasticity. ⋯ It is now clear that the modulation of the AMPA receptor function and membrane trafficking is critical for many forms of synaptic plasticity and a large number of proteins have been identified that regulate this complex process. Here we review the progress over the last two and a half decades and discuss the future challenges in the field.
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A decision is a commitment to a proposition or plan of action based on information and values associated with the possible outcomes. The process operates in a flexible timeframe that is free from the immediacy of evidence acquisition and the real time demands of action itself. ⋯ This Perspective focuses on perceptual decision making in nonhuman primates and the discovery of neural mechanisms that support accuracy, speed, and confidence in a decision. We suggest that these mechanisms expose principles of cognitive function in general, and we speculate about the challenges and directions before the field.
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Perceptual decision making is a computationally demanding process that requires the brain to interpret incoming sensory information in the context of goals, expectations, preferences, and other factors. These integrative processes engage much of cortex but also require contributions from subcortical structures to affect behavior. Here we summarize recent evidence supporting specific computational roles of the basal ganglia in perceptual decision making. These roles probably share common mechanisms with the basal ganglia's other, more well-established functions in motor control, learning, and other aspects of cognition and thus can provide insights into the general roles of this important subcortical network in higher brain function.
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The basolateral amygdala (BLA) and ventral hippocampus (vHPC) have both been implicated in mediating anxiety-related behaviors, but the functional contribution of BLA inputs to the vHPC has never been directly investigated. Here we show that activation of BLA-vHPC synapses acutely and robustly increased anxiety-related behaviors, while inhibition of BLA-vHPC synapses decreased anxiety-related behaviors. ⋯ Furthermore, BLA inputs exerted polysynaptic, inhibitory effects mediated by local interneurons in the vHPC that may serve to balance the circuit locally. These data establish a role for BLA-vHPC synapses in bidirectionally controlling anxiety-related behaviors in an immediate, yet reversible, manner and a model for the local circuit mechanism of BLA inputs in the vHPC.