Ventral motor thalamic input to prelimbic cortex, but not to striatum, mediates cost-benefit decision-making in rats

Abstract

Corticostriatal neurons in prelimbic cortex contribute to decisions that require a trade-off between cost and benefit. The ventral motor thalamus sends dense projections to many cortical areas, including the prelimbic cortex. We investigated whether this input from the ventral motor thalamus to prelimbic cortex contributes to cost-benefit decision-making. Optogenetic inhibition of ventral motor thalamic axon terminals in prelimbic cortex biased rats towards a high cost-high benefit option and, in anesthetized rats, decreased neuronal activity in deep layers of prelimbic cortex. Stimulation of ventral motor thalamic nuclei induced a neuronal response in deep layers of prelimbic cortex and simultaneous optogenetic inhibition of layer 1 inhibitory interneurons similarly decreased neuronal activity. Our results indicate that ventral motor thalamic input to prelimbic cortex mediates cost-benefit decision-making. Significance StatementOur results indicate that ventral motor thalamic input to prelimbic cortex plays a critical role in decisions that require a trade-off between two conflicting reward values. Traditionally, ventral motor thalamic nuclei were primarily associated with motor control, but more recently these thalamic nuclei have been implicated in tasks that require animals to choose between two alternatives. Our results highlight the need to reevaluate the role of the ventral motor thalamic nuclei in cognition. Furthermore, prelimbic cortex and, more generally, prefrontal cortex have been associated with chronic stress and major depressive disorder, highlighting the possibility that ventral motor thalamic nuclei might be involved in these disorders.