Biological theories Flashcards
(105 cards)
explain the case of Phineas Gage: the effect of the accident
Gage suffered no motor or speech impairments as a result of his accident. His memory was intact, and he gradually regained his physical strength. But in fact something was lost to Gage that terrible afternoon. His personality underwent a dramatic shift, changing his disposition to such a degree that his friends barely recognized him. “Gage,” they said, “was no longer Gage.” Once a polite and caring person, Gage became prone to selfish behaviour and bursts of profanity. Previously energetic and focused, he was now erratic and unreliable. He had trouble forming and executing plans. There was no evidence of forethought in his actions, and he often made choices against his best interests. Eventually, his capricious and offensive behaviour cost him his job with the railroad contractors. It was not any physical disability that prevented Gage from working; it was his character. Gage died of a seizure disorder at the age of thirty-eight.
further evidence of prefrontal lobe damage affecting personality
In the years that followed Dr. Harlow’s report, other physicians began noting patients who underwent radical personality changes similar to Gage’s after suffering damage to the frontal lobe. They had trouble holding a job, had little respect for social convention, and seemed indifferent to those around them. They formulated plans but could never seem to carry them out. They made life choices that were clearly against their own best interests. In nearly all cases, an autopsy of these individuals revealed severe damages to the prefrontal cortices.
explain the Yale Study on chimpanzees
he researchers had two monkeys who were especially difficult to work with because they frustrated easily and tended to lash out in retaliation. Researchers then performed surgeries on these monkeys that damaged their frontal lobes. After the surgery, both chimpanzees were docile and cooperative. When the results of this study came to light at a medical conference in 1935, scientists wondered if this kind of surgery could produce similar results in humans. This hypothesis led to an infamous kind of psychiatric surgery performed during the 1940s and 50s known as the frontal lobotomy.
what were lobotomies used for?
to cure aggressive impulses
how do lobotomies work?
robes with sharp ends are inserted behind the eye sockets using a hammer. The probes are inserted so that they have contact with the brain. Once in place, the probes are rotated in an egg beater motion. The physiological effects include intellectual impairment and seizures and paralysis.
what was the effect of lobotomies?
The psychological effects include personality changes. In particular, people who have had a lobotomy have problems with rational planning and socially appropriate behaviours and they often become subdued.
Patients with various kinds of psychosis underwent surgery to purposefully damage their frontal lobes in an effort to cure them of their illnesses. Interestingly, the surgery did seem help some people, especially those with terrible anxiety, but the cost (in term of the side-effects) was huge. It did, however, strengthen the link between the social aspects of personality and the prefrontal cortex.
what does the prefrontal cortex do?
an association area of the brain which means that it integrates many processes from other brain regions, including those specialised for memory and emotion.
what happens if there is damage to the prefrontal cortex?
Damage to the prefrontal cortex does not disrupt the basic function of sensory, memory or emotional systems; it disrupts a person’s ability to synthesise these systems and produce organised social behaviour.
As the case of Phineas Gage illustrates, damage to the frontal lobe can lead to more disinhibited behaviour. In Freudian terms, it is as if the control of the ego had over the id, or perhaps the superego of the id, were reduced.
explain the main functions of the brain
The brain is responsible for thinking.
It interprets all the data you receive from the world around you through your senses.
It controls your body’s temperature, blood pressure, heart rate and breathing.
The brain looks after all the motions your body does automatically e.g. walking, running, reaching, without you having to think about how to do it.
The brain makes up only about 2% of your total body weight but uses 25% of your total blood supply.
define the cerebral cortex
outer layer of the brain; wrinkled and folded in order to cram more brain cells into the limited volume existing inside your skull
define the cerebellum
automatically coordinates all of the limb and muscle movements
define the occipital lobe
processes information from eyes, and turns it into a meaningful picture
define the parietal lobe
controls the sense of touch, and how we use our hands to do things
define the temporal lobe
where signals from our ears are processed, responsible for hearing
define the frontal lobe
controls the ability to speak
define the cerebrum
top of the brain, covered by the cerebral cortex, which contains your memories and language, and correlates information received from your senses. It controls voluntary movement, emotions and does the thinking.
define the pons
responsible for breathing, the regular beating of the heart and other involuntary activities of the body
define the brain stem
collects all the body-controlling messages from the brain and passes them onto the best of the body
define the thalamus
relays incoming messages from the senses to the proper areas of the brain that need to process them
define the hypothalamus
helps to regulate sexual urges, body temperature, growth, thirst and hunger, maternal behaviour, aggression, pleasure and the biological clock which lets you know when to wake and sleep
define the corpus callosum
the connection between the two halves of the brain - the left and right hemispheres
what are the different methods of studying the brain?
EEG (electroencephalography)
ERP (recording event-related potentials)
MEG (magnetoencephalography)
CAT scan (computerised axial tomography)
PET scan (positron emission tomography)
MRI (magnetic resonance imaging)
fMRI (functional magnetic resonance imaging)
NIRS (near-infrared spectroscopy)
how does an EEG work?
Measures the electrical activity of the brain.
Electrodes attached to the scale and positioned in a specific way record electrical activity of neurons.
what are EEGs used for?
Often used to diagnose seizure disorders, tumours, head injuries, degenerative diseases and brain death
Also used in research on brain activity
