Whose side are you on: does serotonin preferentially activate the right hemisphere and norepinephrine the left?

Area of Science:

• Neuroscience
• Neurochemistry
• Brain Lateralization

Background:

• Serotonin (5-HT) and norepinephrine (NE) are key neurotransmitters.
• Their differential effects on brain hemisphere function and lateralization remain largely unexplored.

Purpose of the Study:

• To examine evidence for differential hemispheric effects of 5-HT and NE.
• To propose a novel hypothesis: 5-HT preferentially activates the right hemisphere (RH), and NE the left hemisphere (LH).

Main Methods:

• Review of studies on 5-HT and NE levels and receptor binding.
• Analysis of functional brain imaging, dichotic listening, and EEG/evoked potential data.
• Emphasis on studies involving pharmaceuticals affecting 5-HT and NE systems.

Main Results:

• Evidence suggests a general consistency with the hypothesis.
• A variant proposes 5-HT biases RH functions and NE biases LH functions.
• Not all data definitively support the proposed lateralization.

Conclusions:

• The hypothesis of differential hemispheric activation by 5-HT and NE warrants further investigation.
• Findings may inform understanding of neuropsychiatric disorders linked to monoaminergic system dysfunction.
• Potential implications for understanding drug effects on brain lateralization.