Summary: New research reveals that even light exercise, like jogging or yoga, activates key neurotransmitter systems that enhance memory by stimulating the hippocampus. In a rat model mimicking human exercise, scientists found that dopamine and noradrenaline levels increased in the hippocampus during low-intensity activity.
These neurotransmitters were traced back to specific brainstem regions, the ventral tegmental area and locus coeruleus, which also showed activation. The more these regions were stimulated, the more hippocampal neurons were activated, pointing to a clear link between light movement and improved brain plasticity.
Key Facts:
- Neurochemical Surge: Light exercise increases dopamine and noradrenaline in the hippocampus.
- Brainstem Activation: Activity in the VTA and locus coeruleus correlated with memory-related brain areas.
- Memory Support: Findings support light exercise as a powerful tool for enhancing brain plasticity and memory.
Source: University of Tsukuba
Recent studies have found that light exercise, such as light jogging and yoga, activate the hippocampus, thereby increasing the number of neurons and improving memory.
However, the details of the mechanisms involved, the specific neural circuits activated in the brain during exercise, and the way they activate neurons in the hippocampus are not well understood.
Dopamine, noradrenaline, and serotonin, collectively known as monoamines, are critical neurotransmitters that regulate neuronal activity and plasticity and are produced by neurons that cluster in the brainstem.
The monoamines transmitted to the hippocampus promote neuronal and synaptic plasticity, contributing to the regulation of memory.
Therefore, this research team hypothesized that the monoaminergic system originating in the brainstem may contribute to hippocampal activation during light exercise.
To test this hypothesis, this study established a rat treadmill running model that mimicked the physiological responses in human exercise to evaluate the effects of exercise at different intensities on hippocampal monoamine concentrations and the activation of brainstem monoaminergic neurons.
Dopamine and noradrenaline levels increased in the hippocampus, even with light exercise. Furthermore, in the brainstem, the dopamine-producing neurons in the ventral tegmental area and noradrenaline-producing neurons in the locus coeruleus, both of which could be the origins of these neurotransmitters, were also activated.
Furthermore, the activation of these two regions were positively correlated with hippocampal neuronal activation.
The study findings indicate that dopamine originating from the ventral tegmental area and noradrenaline originating from the locus coeruleus may significantly influence the neural circuits that activate the hippocampus during light exercise.
Further research is required to clarify the neural circuit mechanisms of memory enhancement activated by light exercise and support the effectiveness of exercise prescriptions on enhancing memory and brain plasticity.
Funding: This research was supported in part by KAKENHI Grants-in-Aid for Scientific Research (A) (18H04081; 21H04858; 24H00670) (to H.S.); KAKENHI Grants-in-Aid for Scientific Research on Innovative Areas: Next Generation Exercise Program for Developing Motivation, Body and Mind Performance (16H06405) (to H.S.); Japan Science and Technology Agency (JST)-Mirai Program (JPMJMI19D5) (to H.S.); Grant-in-Aid for Japan Society for the Promotion of Science Fellowships (20J20887) (to T.H.).
About this exercise and neuroplasticity research news
Author: SOYA Hideaki
Source: University of Tsukuba
Contact: SOYA Hideaki – University of Tsukuba
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Light-exercise-induced dopaminergic and noradrenergic stimulation in the dorsal hippocampus: Using a rat physiological exercise model” by SOYA Hideaki et al. FASEB Journal
Abstract
Light-exercise-induced dopaminergic and noradrenergic stimulation in the dorsal hippocampus: Using a rat physiological exercise model
Exercise activates the dorsal hippocampus that triggers synaptic and cellar plasticity and ultimately promotes memory formation.
For decades, these benefits have been explored using demanding and stress-response-inducing exercise at moderate-to-vigorous intensities.
In contrast, our translational research with animals and humans has focused on light-intensity exercise (light exercise) below the lactate threshold (LT), which almost anyone can safely perform with minimal stress.
We found that even light exercise can stimulate hippocampal activity and enhance memory performance.
Although the circuit mechanism of this boost remains unclear, arousal promotion even with light exercise implies the involvement of the ascending monoaminergic system that is essential to modulate hippocampal activity and impact memory.
To test this hypothesis, we employed our physiological exercise model based on the LT of rats and immunohistochemically assessed the neuronal activation of the dorsal hippocampal sub-regions and brainstem monoaminergic neurons.
Also, we monitored the extracellular concentration of monoamines in the dorsal hippocampus using in vivo microdialysis. We found that even light exercise increased neuronal activity in the dorsal hippocampal sub-regions and elevated the extracellular concentrations of noradrenaline and dopamine.
Furthermore, we found that tyrosine hydroxylase-positive neurons in the locus coeruleus (LC) and the ventral tegmental area (VTA) were activated even by light exercise and were both positively correlated with the dorsal hippocampal activation.
In conclusion, our findings demonstrate that light exercise stimulates dorsal hippocampal neurons, which are associated with LC-noradrenergic and VTA-dopaminergic activation.
This sheds light on the circuit mechanisms responsible for hippocampal neural activation during exercise, consequently enhancing memory function.