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PSYC18 – Chapter 6 TextBook Notes
Chapter 6: Emotions and the Brain
•Treatment of the survivors of the sleeping sickness (encephalitis lethargic), a disease that
started in Europe in the winter of 1916-17.
oContinued for 10 years, affected five million people
oVictims fell into a suspended state as if they were ghost/zombies, they sat
motionless and speechless all day observing but doing nothing.
oIn 1969, a precursor of the transmitter substance dopamine was discovered that
became the drug, i-Dopa.
Some of the transmitter functions were restored
There was a rise in emotions of joy and excitement, mood swings
•This case illustrates how brain regions and neurotransmitters are intimately involved in
How do brain mechanisms of emotions work?
•Human brain has about 100,000,000,000 neurons
oThey each may have 10,000 – 150,000 synapses.
•Neuroimaging: a machine monitors biochemical events in a series of conceptual slices
through a person’s brain, while a computer takes this information and constructs visual
images of the brain to show which regions have been metabolically most active. These are
oPositron Emission Tomography (PET)
oFunctional Magnetic Resonance Imagining (fMRI)
Movie pictures are constructed to show brain activity changing over time
in the course, i.e. different emotional states.
•Physiologists have recorded the electrical activity of single neurons/groups of neurons.
oAnatomy, lesions, stimulation, pharmacology, electrical recording.
•hindbrain includes regions that control basic physiological processes
•medulla regulates cardiovascular activity
•pons controls human sleep
•cerebellum is involved in controlling motor movements
•forebrain includes the thalamus which is involved in integrating sensory information
othe forebrain also includes the limbic system
Limbic system – with structures involved in emotions like the amygdale
and the cortex which most sets human brain apart from other species.
The growth of the cortex is closely associated with our abilities to lead
complex social lives.
•The frontal lobes of the cortex is also associated with planning and
intentional action, as well as emotional regulation.
•the hippocampus which is critical for memory processes
•hypothalamus which regulates important biological functions – like eating, sexual
behaviour, aggression, and bodily temperature.
•350 years ago, Decartes proposed that the sensory nerves were controlled by strings and
hydraulics human reflex. Involving events (stimuli) that excite sensory receptiors,
which send messages to the sensory nerves to the brain, then send signals to mortor
nerves to work the muscles
oHowever, emotions are more than reflexes
Early research on brain lesions and stimulation
oProposed the first substantial theory of the brain mechanisms of emotion
oIndicated that cats deprived of their cortext were liable to make sudden,
inappropriate and ill-directed attacks. “shame rage”
If fed artificially and carefully tended, these cats can live for a long time,
but would show few spontaneous movements expect this angry shame
oCannon proposed that the cortex usually inhibits this expression
PSYC18 – Chapter 6 TextBook Notes
•Hess and Brugger
oResearch on lesions with experiments using electrical stimulation that elicited
angry behaviour not from the thalamus, but from the hypothalamus which lies
jjust below it.
•Cannon and Bard
oLower levels of the brain (the hind brain) are reflex pathways realated to simple
functions like postures and movements
oAt the next level, structures of emotions
oAt the highest level, the cortext controls all levels below it.
According to this argument, children have uncontrolled emotions until
their cortext developed sufficiently to inhibit their lower functions.
Brain trauma leads to the diminished activity of the higher regions of the
The limbic system
oSensory impulses from the body and the outside world reach the thalamus and
split into 3 main pathways
One goes to the striatal region, the stream of movement
One goes to the neocortext, the stream of thought
One goes to the limbic system with its many connections to the
hypothalamus, the stream of feeling
•Eg. Rabies virus attacks the limbic system and that rabies patients
sometimes experience extreme terror.
•Also tumours in the limbic area sometimes cause a loss of feeling
and of memory.
oProposed that the human forebrain includes 3 distinct systems each with a distinct
phase of vertebrae evolution