The brain's RAGE neurocircuitry:
In Affective Neuroscience, Panksepp points to the work of Walter Hess during the 1930s in determining that electrical stimulation to certain brain areas can produce rage behavior in animals. Hess won the Nobel Prize in 1949. Panksepp writes: "It has long been known that one can enrage both animals and humans by stimulating very specific parts of the brain, which parallel the trajectory of the FEAR system." He adds: "Brain tumors that irritate the circuit can cause pathological rage, while damage to the system can promote serenity."
Panksepp writes: "The core of the RAGE system runs from medial amygdaloid areas downward, largely via the stria terminalis [a bundle of nerve fibers] to the medial hypothalamus, and from there to specific locations within the PAG [periaqueductal gray] of the midbrain."
In the illustration to the left (links to source), the amygdala is labeled on the right and the thin string-like stria terminalis, also labeled on the right, links the amygdala to the hypothalamus, which lies hidden beneath the thalamus in this illustration. Although not labeled, the periaqueductal gray lies in the yellow center area that represents the midbrain.
Regarding the kinds of stimuli that can access RAGE circuitry, Panksepp points to such things as body surface irritation or when one does not receive an expected reward. He explains that the most common triggers of rage "are the irritations and frustrations that arise from events that restrict freedom of action or access to resources." He points out that "a human baby typically becomes enraged if its freedom of action is restricted simply by holding its arms to its sides." Activation of RAGE circuits is "accompanied by an invigoration of the musculature, with corresponding increases in autonomic indices such as heart rate, blood pressure, and muscular blood flow." According to Panksepp, the phrase "getting hot under the collar," is accurate in that body temperature also increases during rage.
In the image below left, the medial hypothalamus is labeled in red lettering. This image is from S.S. Nussey and S.A. Whitehead, Endocrinology, NCBI bookshelf (image links to source). For some perspective, the image below right depicts the location and relative size of the hypothalamus as a whole (image links to source).
RAGE circuitry is organized hierarchically. Lesions of higher areas such as the amygdalae do not diminish responses from lower areas, while damage to lower areas such as the medial hypothalami and periaqueductal gray zones dramatically diminishes rage evoked from the amygdalae.
The image below (links to source) illustrates the position of the periaqueductal gray of the midbrain and is taken from professor Robert Lynch's course, "Territoriality and Aggressive Behavior," at the University of Colorado at Boulder.
Areas of the frontal cortex containing reward-relevance neurons influence RAGE circuitry.
Cortical areas called frontal eye fields, which help direct eye movements to especially prominent objects in the environment, influence RAGE circuitry.
The orbitoinsular cortex, especially the insular area—where a multitude of senses converge including pain and perhaps hearing—may provide specific sounds direct access to RAGE circuitry. In humans, these sounds may include, for example, an angry voice.
The medial hypothalamus provides powerful input related to energy (food) requirements and sexual matters thus influencing RAGE circuitry activated in pursuit of such resources.
A lower area, the vestibular complex, may help enrage animals when their bodily orientation is disturbed.
Cell groups such as the norepinephrine-producing loci coerulei and serotonin-producing raphe nuclei, which exert modulatory control over all behaviors, also influence RAGE circuits.
The nucleus of the solitary tract, which collects information via the vagus nerve that is probably related to processes such as heart rate and blood pressure, inputs to RAGE circuitry.
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