Medial Prefrontal Cortex Interacts with the Anteromedial Thalamus in Motivation and Dopaminergic Activity

Abstract

How does the prefrontal cortex (PFC) regulate motivated behavior? Our experiments characterize the circuits of the PFC regulating motivation, reinforcement and dopamine activity, revealing a novel cortico-thalamic loop. The stimulation of medial PFC (mPFC) neurons activated many downstream regions, as shown by functional MRI. Axonal terminal stimulation of mPFC neurons in downstream regions, including the anteromedial thalamic nucleus (AM), reinforced behavior and activated midbrain dopaminergic neurons. The stimulation of AM neurons projecting to the mPFC also reinforced behavior and activated dopamine neurons, and mPFC and AM showed a positive-feedback loop organization. Reciprocal excitatory functional connectivity, as well as co-activation of the two regions, was found in human participants who watched reinforcing videos. Our results suggest that this cortico-thalamic loop regulates motivation, reinforcement and dopaminergic neuron activity.

The anterior thalamic nuclei and cognition: A role beyond space?

“…However, a recent report suggests that the anterior thalamic nuclei, and in particular the anteromedial thalamic nucleus, may have a hitherto unappreciated role in processes that support instrumental learning ( Yang et al, 2020 ). These authors found that optogenetic stimulation of medial prefrontal cortex terminals within the anteromedial thalamic nucleus supported intracranial self-stimulation, with animals readily acquiring a lever press response to obtain photo-stimulation of these terminal fields.…”

“…These authors found that optogenetic stimulation of medial prefrontal cortex terminals within the anteromedial thalamic nucleus supported intracranial self-stimulation, with animals readily acquiring a lever press response to obtain photo-stimulation of these terminal fields. Interestingly, other thalamic targets of the medial prefrontal cortex only supported modest levels of intracranial self-stimulation (mediodorsal thalamic nucleus) or none at all (nucleus reuniens) ( Yang et al, 2020 ). The same authors then confirmed that the reciprocal connections between the anteromedial thalamic nucleus and medial prefrontal cortex also support intracranial self-stimulation.…”

“…The same authors then confirmed that the reciprocal connections between the anteromedial thalamic nucleus and medial prefrontal cortex also support intracranial self-stimulation. Again, animals readily acquired a lever response to obtain photo-stimulation from optic-fibres targeting either neurons expressing channelrhodopsin within the anteromedial thalamic nucleus or their terminations in the medial prefrontal cortex ( Yang et al, 2020 ). Consistent with the suggestion that these effects reflect reinforcement mechanisms, stimulation of these pathways in either direction resulted in activation of dopaminergic neurons in the ventral tegmental area ( Yang et al, 2020 ).…”

“…Again, animals readily acquired a lever response to obtain photo-stimulation from optic-fibres targeting either neurons expressing channelrhodopsin within the anteromedial thalamic nucleus or their terminations in the medial prefrontal cortex ( Yang et al, 2020 ). Consistent with the suggestion that these effects reflect reinforcement mechanisms, stimulation of these pathways in either direction resulted in activation of dopaminergic neurons in the ventral tegmental area ( Yang et al, 2020 ). These results are preliminary and there is a clear need for further control experiments including an assessment of lever pressing for photo-stimulation in with animals not transfected with channelrhodopsin, the findings are, nonetheless, intriguing and raise questions about the role of the anteromedial thalamic nucleus and its interactions with prefrontal cortex in the control of goal-directed behaviour.…”

Analyzes How Short-Form Video Apps Affects Popular Culture and People's Entertainment

“…The number of users of short video software continues to grow, and more and more people will watch short videos as a form of leisure and entertainment (Yaqi et al, 2021). The important reason for the popularity of short videos is that the video content stimulates the brain and causes the brain to release dopamine, which makes people continue to search for dopamine secreting content in the ocean of short videos, and ultimately indulge in behavior (Yang et al, 2020). This makes many people unable to resist the short-lived pleasure brought by the software, and the emptiness brought by this happiness will make people even more hope to use the software to have fun (Omar & Dequan, 2020).…”