Donald Hebb (1904-1985) was the first to come up with a way to tell the difference between short-term and long-term memory. When the brain receives an input, like something that is seen or heard, a sensory memory keeps a copy of what is seen or heard, but this memory lasts for only about a few seconds. Anything that is retained in the brain longer depends on our selective attention, things that we "notice" are kept in short-term memory for up to a few minutes. This memory is thought to be dependent on electrical activity in the brain and is easily destroyed by interruption or interference.  Short-term memory includes iconic memory as well, which holds visual images; acoustic memory, to hold sounds; and working memory, which is an active process to keep a memory until it is put to use.
Some chronic stresses stem from traumatic, early childhood experiences that become internalized and remain forever painful and present. Some experiences profoundly affect personality. A view of the world, or a belief system, is created that causes unending stress for the individual (., the world is a threatening place, people will find out you are a pretender, you must be perfect at all times). When personality or deep-seated convictions and beliefs must be reformulated, recovery requires active self-examination, often with professional help.
The areas of the brain where cannabinoid receptors are most prevalently located are consistent with the behavioral effects produced by cannabinoids. Brain regions in which cannabinoid receptors are very abundant are the basal ganglia , associated with movement control; the cerebellum , associated with body movement coordination; the hippocampus , associated with learning , memory, and stress control; the cerebral cortex , associated with higher cognitive functions; and the nucleus accumbens , regarded as the reward center of the brain. Other regions where cannabinoid receptors are moderately concentrated are the hypothalamus , which regulates homeostatic functions; the amygdala , associated with emotional responses and fears ; the spinal cord , associated with peripheral sensations like pain; the brain stem , associated with sleep , arousal , and motor control; and the nucleus of the solitary tract , associated with visceral sensations like nausea and vomiting .