Habenula-Induced Inhibition of Midbrain Dopamine Neurons Is Diminished by Lesions of the Rostromedial Tegmental Nucleus

摘要: Neurons in the lateral habenula (LHb) are transiently activated by aversive events and have been implicated associative learning. Functional changes associated with tonic phasic activation of LHb often attributed to a corresponding inhibition midbrain dopamine (DA) neurons. Activation GABAergic neurons rostromedial tegmental nucleus (RMTg), region that receives dense projections from projects strongly monoaminergic nuclei, is believed underlie transient DA LHb. To test this premise, effects axon-sparing lesions RMTg were assessed on LHb-induced cell firing anesthetized rats. Quinolinic acid decreased number NeuN-positive significantly while largely sparing cells neighboring regions. Lesions reduced both inhibited by, duration resulting from, stimulation. Although rate was not altered, regularity increased RMTg-lesioned Locomotor activity an open field also elevated. These results first show contribute directly support widely held proposition mesopontine tegmentum important component pathway enables encode negative valence failed expectations stimuli. SIGNIFICANCE STATEMENT Phasic motivate guide future behavior. inhibits transiently, providing neurobiological representation learning models incorporate reward prediction errors. Anatomical evidence suggests occurs via nucleus, but hypothesis has yet be tested directly. Here, we attenuate habenula-induced significantly. data substantial role for feedforward