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~ Phrenology ~
Theory that claimed that bumps on the skull reveled mental abilities and character traits.
Santiago Ramon y Cajal (1852-1934)
Described gaps between nerve cells (synaptic gap/"photoplasmic kiss" and concluded that nuerons must function independently within the nervous system.
Sir Charles Sherrington (1857-1952)
Found that neural impulses were taking too long to travel a neural pathway so he inferred that there must be a brief interruption in the transmission. It was the crossing of the synapse.
Candace Pert & Solomon Snyder (1973)
Attached a radioactive tracer to morphine and discovered that the opiate drug (elevates mood + eases pain) was taken up by receptors in areas linked to mood and pain sensation. It was later found that the brain does contain several types of neurotransmitter molecules similar to morphine (natural opiates).
(Posner & Raichle, 1998)
(Martin & Others, 1996)
(Schlaug & Others, 1995)
(Kim & Others, 1997)
(Shayitz & Others)
New Revelations Due to Brain-Imaging Instruments:
(Posner & Raichle, 1998) - reading and remembering words involved similar brain areas
(Martin & Others, 1996) - through PET scans found different parts of the brain light up when you say the name of an animal than if you say the name of a tool
(Schlaug & Others, 1995) - musicians with perfect pitch had a larger-than-average neural area int eh left brain
(Kim & Others, 1997) - found that if a person learns a 2nd language early, it appears in same place as the 1st
(Shayitz & Others) - in a rhyming task, men use the left brain more whereas women use both sides
If you cut the top of a cat's brain stem, it will be able to breath, run, climb and groom but cut off from the higher region of the brain, it won't purposefully run or climb to get food. (The brain stem and medulla are responsible for automatic survival behaviors)
Giuseppe Moruzzi & Horace Magoun (1949)
Found that the reticular formation is involved with arousal - if you stimulate a cat's reticular formation, it becomes alert and awake but if it is severed, it lapses into a coma and never awakens.
Llinas & Ribary (2001)
Discovered that the thalamus coordinates the brain's electrical oscillations which slow during sleep and speed up to produce waking consciousness
Anderson & Phelps, 2000
Poremba & Gabriel, 2001
Amygdala - 2 almond shaped neural cluster linked to emotion; influences fear and aggression
Heinrich Klüver & Paul Bucy, 1939
Surgically lesioned part of rhesus monkey's brain, including the amygdala. The normally angry monkey was calm even though they did things to provoke him. Supports the role of the amygdala in fear and aggression. Similar lesioning in humans (psychosurgery) has not produced favorable results and is rarely used because it is considered unethical.
James Olds & Peter Milner (1954)
James Olds (1958)
Discovered that parts of the hypothalamus serve as pleasure centers - accidentally placed an electrode in a rat's hypothalamus and it kept going back to the stimuli that gave it pleasure.
In 1958, Olds let rats trigger their own stimulation by pressing a pedal, which they did at a feverish pace until they dropped from exhaustion and would even cross an electrified floor that a starving rat wouldn't cross to reach food in order to trigger the stimulus.
Sanjay Talwar & others (2002)
Was able to train rats never exposed to the outdoors to turn left or right via brain stimulation. Suggests future application in search and rescue.
Blum & others, 1996
Reward deficiency syndrome, a genetically predisposed deficiency in the brain for a sense of pleasure - addictive behavior may stem from this
Gustav Fritsch & Eduard Hitzig (1870)
Found that by stimulating the motor cortex, they could make different parts of a dog's body to move. Also found that stimulation in one hemisphere often provoked movement on the opposite side of the body.
Otfrid Foerster & Wilder Penfield
Found how much of the motor cortex was taken up for different body parts. Body parts requiring precise control (fingers/mouth) took up the most cortical space.
Found that by stimulating certain parts of the motor cortex, you could have certain responses (such as making your ball in a fist or smiling).
If a sensitive region is lost (like a finger), then the region in the cortex extends to the adjacent sensitive regions (other fingers)
Bavalier & others; Pantev & others
Good pianists have a larger-than-average auditory cortex and deaf people have an enhanced visual cortex with greater peripheral vision.
Paul Broca & Broca's Area
Discovered that damage to an area of the frontal lobe, usually in the left hemisphere, known as Broca's area, controls language expression and direct muscle movements involved in speech. Damage to this area impairs speaking, or aphasia. Shows that language processing is localized.
Wernicke & Wernicke's Area
Wernike's area controls language reception - it is a brain area involved in language comprehension and expression, usually in the left temporal lobe. Damage to this area impairs understanding, called aphasia. Shows that language processing is localized.
Found that the conscious left hemisphere is the interpreter, which instantly constructs theories to explain behavior. The right hemisphere understands simple requests and perceives objects.
Discovered while he was working with epilepsy, that cutting the corpus collosum (the structure that connects the two hemispheres of the brain) could reduce or eliminate seizures. Left-brain and right-brain theory stems from his work.
Kasamatsu & Hirai, 1999
Studied how sensory deprivation can affect the brain. They studied Buddhist monks going on a 72 hour pilgrimage to a holy mountain in Japan. The didn't drink water or eat, didn't speak, they were exposed to cold, late autumn weather. They started to have hallucinations (their ancestors being near them) and they attributed this to the increased serotonin levels in the brain.
Martinez & Kesner
Determined that acetylcholine was an important neurotransmitter in memory. They had rats run a maze for food and injected one group with scopolamine, which blocked the Ach sites; one group with physostigamine, which allowed the Ach levels to be at a high state. The rats with teh scopolamine were slower and made more errors. The physostigamine group were much faster and very few errors.
Phineas Gage Incident
Harlow studied Phineas Gage, 25 year old railroad foreman who had an accident where a metal pole went through his skull. Although he was alive, it destroyed his balance between intellectual capacity and emotions. He had the intellectual capacity of a child but the animal passions of a strong man.
Found that electrically stimulating certain areas of the brain (pleasure centers) produced pleasure in depressed patients.
Hetherington & Ranson
Lesioned the ventromedial hypothalamus in rats, which caused them to increase their food intake dramatically and doubled their weight. So the hypothalamus plays a role in regulating their hunger.
Gur et. al
Found more active metabolism in primitive brain centres controlling violence in men than in women.
Hubel & Wiesel (1965)
Demonstrated that the brain could change as a response to environmental input. Environmental enrichment can modify the brain, especially the cerebral cortex, which is the area of higher cognitive functioning.
Rosenzweig & Bennett, 1972
Measured the effect of an enriched or deprived environment on the development of of neurons in the cerebral cortex. Rats that had toys to play with had more cerebral thickness than rats that had no toys. Rats that also socialize with others tend to have more development as well.
Richard Davidson (2004)
Wanted to see if meditation could change brain activity. When monks and newbies meditated there was an increase in gamma waves which are linked to higher reasoning faculties; after stopping the gamma levels dropped to normal in the newbies but the monks' levels stayed the same. Meditation can have long term effects on the brain and the brain does adapt to stimulation whether its from your environment or your own thinking.
Mozart Effect (Rauscher et. al 1993) & Thompson et. al
Listening to Mozart will temporarily increase spatial reasoning ability. Recent studies found that it has little to with Mozart and a lot to do with arousal. When people do something they like, they improve their spatial abilities (Thompson et. al)
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