How the Brain Works Signalling after injury
How the Brain Works
Signalling in the brain during illness and after injury
Studies of astroglia cells in cell cultures show that after injury, these cells reduce their ability to handle glutamate effectively. As a result, some glutamate remains in the synapse region, leading to nonspecific activation of nerve cells. Additionally, less glutamate enters the astrocytes, which is problematic because astrocytes use glutamate to produce new energy and glutamine, which is delivered to nerve cells to produce new glutamate for continued signaling. This also causes astrocytes to swell.
Although studies of brain metabolism after illness or injury are not fully established, it seems that immediately after an injury, the brain needs more energy for healing processes, but the energy supply decreases over time. This suggests that the brain’s signaling system does not function normally during illness and injury, leading to a lack of available energy and decreased efficiency in signaling between brain cells.
Experimental data and human studies suggest that dopamine signaling decreases in several brain areas following a brain injury. Dopamine is involved in movement and cognitive functions, including concentration and attention. Reduced dopamine signaling in the frontal parts of the brain leads to impaired concentration and decreased attention, core symptoms of brain fatigue. Treatment with dopamine stimulators like methylphenidate can increase concentration capacity and improve attention.
Serotonin is important for emotional life, and its levels are lowered during depression. Antidepressant drugs increase serotonin levels in the synapses. After a brain injury, serotonin levels also decrease in several brain areas, which may explain the emotional lability and irritability in brain-tired individuals. Very low doses of antidepressant drugs can alleviate these symptoms, supporting serotonin’s involvement in brain fatigue.
Other signaling substances, such as norepinephrine and acetylcholine, also decrease after brain damage. Some effects on brain fatigue have been achieved by adding these substances in drug form, though results vary.