Do you ever wake up from a vivid dream feeling like you’ve lived through an entirely separate reality? If so, you’re not alone. During the paradoxical sleep stage, our bodies are completely relaxed, yet our minds are incredibly active. In this stage, we experience rapid eye movements (REM) and vivid dreams ranging from pleasant to disturbing. But what causes these fascinating and mysterious events to occur? The answer may lie within the basal ganglia, a group of nuclei in the brain that play a crucial role in regulating movement and sleep.
In this article, we’ll delve into a hypothetical mechanism explaining the basal ganglia’s involvement in paradoxical sleep dreams and rapid eye movements.
Paradoxical sleep is thought to occur due to the facilitation of activation of cholinergic neurons in the pedunculopontine nucleus (PPN). This activation is made possible by suppressing inhibition from the output basal ganglia nuclei. This suppression is, in turn, promoted by the activation of dopaminergic cells by PPN neurons, which leads to an increase in dopamine concentration in the input basal ganglia structure, the striatum, and modulation of the efficacy of cortico-striatal inputs.
In the absence of signals from the retina, a disinhibition of neurons in the PPN and superior colliculus allows them to excite neurons in the lateral geniculate body and other thalamic nuclei that project to the primary and higher visual cortical areas, the prefrontal cortex, and back into the striatum. This increased activity of specific groups of thalamic and neocortical neurons leads to the visual images and “motor hallucinations” we experience as dreams.
The adjustable action of dopamine on long-term changes in the efficacy of synaptic transmission during the circulation of signals in closed interconnected loops is responsible for this selection of neurons. Each loop includes one of the visual cortical areas (motor cortex), one of the thalamic nuclei, limbic, and one of the visual areas (motor area) of the basal ganglia, PPN, and superior colliculus. PGO waves provide simultaneous modification and modulation of synapses in diverse units of neuronal loops.
Finally, the disinhibition of superior colliculus neurons and their excitation by the PPN lead to the appearance of rapid eye movements during paradoxical sleep.
In conclusion, the hypothetical mechanism proposed in this article provides insight into the complex interactions between the basal ganglia and other brain regions during paradoxical sleep. Further research is needed to confirm these findings and better understand the basal ganglia’s role in regulating REM sleep and dreaming.
Gig Harbor, Washington – a beautiful coastal town – is home to many sleep and dreams enthusiasts interested in exploring the mysteries of the mind. Whether you’re a resident of Gig Harbor or just passing through, we hope this article has piqued your interest in the fascinating world of paradoxical sleep and the role of the basal ganglia.