Role in Defensive Behavior
Stimulation of the dorsal and lateral aspects of the PAG (in the rat) can provoke defensive responses characterised by freezing immobility, running, jumping, tachycardia, and increases in blood pressure and muscle tonus. In contrast, stimulation of the caudal ventrolateral PAG can result in an immobile, relaxed posture known as quiescence, whereas its inhibition leads to increased locomotor activity.
Lesions of the caudal ventrolateral PAG can greatly reduce conditioned freezing, whereas lesions of the dorsal aspect can reduce innate defensive behavior, virtually "taming" the animal.
Read more about this topic: Periaqueductal Gray
Famous quotes containing the words role, defensive and/or behavior:
“The role of the intelligence—that part of us which affirms and denies and formulates opinions—is merely to submit.”
—Simone Weil (1909–1943)
“Stay-at-home mothers, . . . their self-esteem constantly assaulted, . . . are ever more fervently concerned that their offspring turn out better so they won’t have to stoop to say “I told you so.” Working mothers, . . . their self-esteem corroded by guilt, . . . are praying their kids turn out functional so they can stop being defensive and apologetic and instead assert “See? I did do it all.””
—Melinda M. Marshall (20th century)
“One cannot demand of a scholar that he show himself a scholar everywhere in society, but the whole tenor of his behavior must none the less betray the thinker, he must always be instructive, his way of judging a thing must even in the smallest matters be such that people can see what it will amount to when, quietly and self-collected, he puts this power to scholarly use.”
—G.C. (Georg Christoph)