8.13 : Physiology of Emotion

The physiology of emotions is a multifaceted process involving the autonomic nervous system, brain structures, hormones, and neurotransmitters. This intricate interplay dictates how emotions manifest in the body and influence behavior.

Autonomic Nervous System

The autonomic nervous system (ANS) plays a critical role in emotional responses by regulating involuntary physiological functions. It consists of two main components: the sympathetic and parasympathetic systems. The sympathetic system activates during emotional arousal, increasing heart rate, accelerating breathing, dilating pupils, and causing dry mouth. These physiological responses, commonly known as the "fight or flight" reaction, prepare the body to respond to stress or danger. Conversely, the parasympathetic system promotes relaxation and recovery, restoring the body to a calm state after a stressful event.

Brain Structures and Emotional Regulation

Critical brain structures like the hypothalamus and amygdala are central to regulating emotions. The hypothalamus connects the nervous system to the endocrine systems, influencing hormone release. The amygdala is essential for processing emotions such as fear and aggression. Individuals with damage to the amygdala show impaired ability to recognize these emotions in others, highlighting its importance in social and emotional perception. The cerebral cortex also contributes to emotional processing, with its hemispheres showing distinct roles: the left hemisphere is more active during positive emotions, such as happiness, while the right hemisphere is more active during negative emotions, including sadness and anxiety.

Hormones and Neurotransmitters

Hormonal fluctuations significantly impact emotional states. When elevated, a stress hormone called cortisol increases stress and anxiety. In contrast, oxytocin, often called the "love hormone," fosters social bonding and feelings of trust. Neurotransmitters also modulate emotions; low serotonin levels are linked to aggression, while dopamine is associated with pleasure and reward mechanisms. This complex network of systems and signals underlies the diverse range of human emotions.