section_path: Physiology
section_name: Physiology
paragraph_text: Physiology
  
  Neuroscience has shown that emotions are generated by multiple structures in the brain. The rapid, minimal, and evaluative processing of the emotional significance of the sensory data is done when the data passes through the amygdala in its travel from the sensory organs along certain neural pathways towards the limbic forebrain. Emotion caused by discrimination of stimulus features, thoughts, or memories occurs when its information is relayed from the thalamus to the neocortex. Based on some statistical analysis, some scholars have suggested that the tendency for anger may be genetic. Distinguishing between genetic and environmental factors requires further research and actual measurement of specific genes and environments.
  
  In neuroimaging studies of anger, the most consistently activated region of the brain was the lateral orbitofrontal cortex. This region is associated with approach motivation and positive affective processes.
  
  The external expression of anger can be found in physiological responses, facial expressions, body language, and at times in public acts of aggression. The rib cage tenses and breathing through the nose becomes faster, deeper, and irregular. Anger activates the hypothalamic–pituitary–adrenal axis. The catecholamine activation is more strongly norepinephrine than epinephrine. Heart rate and blood pressure increase. Blood flows to the hands. Perspiration increases (particularly when the anger is intense). The face flushes. The nostrils flare. The jaw tenses. The brow muscles move inward and downward, fixing a hard stare on the target. The arms are raised and a squared-off stance is adopted. The body is mobilized for immediate action, often manifesting as a subjective sense of strength, self-assurance, and potency. This may encourage the impulse to strike out.