Chapter 6 ± Emotions and the Brain
x Awakenings (1973) by Oliver Sacks describes treatment of survivors with sleeping sickness, a disease that
started in Europe, eventually spreading throughout the world.
x Such emotions, passions, and appetites, sexual and otherwise, were common with the administration of L-
How do brain mechanisms of emotion work?
x Hindbrain, includes regions that control basic physiological processes
o Medulla ± regulates CV activity
o Pons ± controls sleep
o Cerebellum ± involved in controlling motor movement
o Thalamus ± integrating sensory information
o Hippocampus ± critical for memory processes
o Hypothalamus ± behavior, aggression and bodily temperature
o Limbic system ± amygdala (involved in emotions), and cortex (associated with abilities to lead
complex social lives + planning and intentional action)
x Nerve messages are carried not by strings or hydraulics but by electric and chemical signals.
x Emotions, however, are more than reflexes.
Early research on brain lesions and stimulation
x Bard (1928) and deprivation of cortex in cats ± found they were liable to make sudden, inappropriate and ill-
GLUHFWHGDWWDFNVFDOOHG³VKDPUDJH´Æ proposed that the cortex inhibits this expression
x Jackson (1959) ± lower levels of the brain are reflex pathways related to simple functions. At the highest and
most recently evolved level, the cortex controls all level below it.
x Similarly, brain trauma (ex: PG) leads to the diminished activity of higher regions of the brain, releasing the
lower ones from inhibitions.
The limbic system
x Three main pathways (Papez)
o 1) striatal region ± the stream of movement
o 2) neocortex ± the stream of thought
o 3) limbic system with its many connections to the hypothalamus ± the stream of feeling.
x MacLean proposed that the human forebrain includes three distinct systems
o Most basic part is called the striatal region (REPTILIAN)
Devoted to scheduling and generating basic behaviors, including preparation and
establishment of a home site, marking and patrolling, etc.
Huntingdon¶s chorea ± unable to organize daily activities; tendency to do nothing.
x Striatal region damaged.
o Second is the limbic system (PALEOMAMMALIAN)
We are social creatures
Closely linked to the hypothalamus, which not only controls the ANS but via the pituitary
gland, controls also the body¶s hormonal system
Stimulation of septal region induces a tendency to approach
If amygdala is removed, aggressive monkeys became docile.
Epilepsy; nerve cells fire together in a self-sustaining pattern; production of auras,
subjective states that often include strong emotions.
Six feelings occur in this way: desire, fear, anger, dejection (sadness), gratulant feelings
(happiness, insight, achievement), and feelings of affection
Using PET, brain regions were found to increase in activity when people relived specific
emotions were almost all sub-cortical. In contrast, neural activity in the cortex tended to
decrease when emotions were experienced.
o (NEOMAMMALIAN) ± cortex, largest region, distinct to higher mammals, 80% in humans
Amygdala as an emotional computer