The Brainstem in Emotion: A Review.

Area of Science:

• Neuroscience
• Psychology
• Behavioral Science

Background:

• Emotions arise from integrated neural networks modulating arousal, autonomic function, motor control, and somatosensation.
• Prior research on the neuroanatomic basis of emotion has predominantly focused on cortical structures, overlooking the brainstem's significant role.
• Technical challenges in studying complex brainstem circuits are being overcome by advances in neuroimaging.

Purpose of the Study:

• To provide a conceptual framework for studying brainstem involvement in human emotions.
• To highlight the brainstem's critical role in emotion through its Ascending, Descending, and Modulatory networks.

Main Methods:

• Review of existing literature on brainstem structures and their functions in emotional processing.
• Conceptual integration of findings from neuroscience, psychology, and behavioral science.
• Focus on neuroimaging advances accelerating research into the brainstem's role in emotion.

Main Results:

• The 'emotional brainstem' comprises three interconnected networks: Ascending (sensory input), Descending (motor output), and Modulatory (neurotransmitter pathways).
• Integration within these networks occurs at various brainstem levels, progressing to the hypothalamus, thalamus, and ultimately the cerebral cortex.
• Bidirectional interactions between ancient brainstem networks and newer cortical regions shape emotional evaluation and behavioral responses.

Conclusions:

• The brainstem is fundamental to emotional processing, contributing to sensory evaluation and triggering behavioral responses.
• This framework facilitates a deeper understanding of the brainstem's contribution to the spectrum of human emotions.
• Future research can leverage this model to explore the neuroanatomic basis of emotion more comprehensively.