GTPSY, Case Studies Flashcards
Phineas Gage case study
He was working on a railroad bed, and was using an iron rod to put the explosive powder into the hole, but the powder detonated, sending the 43-inch rod through his left cheek and out the top of his skull, before landing 80 feet away. After the accident, his personality changed. He became ecstatic and unpredictable, and had trouble maintaining a job afterwards. He later died due to the complications of epilepsy.
Patient H.M. before the surgery
He faced a brain injury as a child and developed epilepsy. His seizures were getting more and more severe, and he became disabled from his condition, so he volunteered for a surgery that may fix it. The doctor performed a procedure that involved removing a portion of his temporal lobe, including his hippocampus and amygdala from both sides of his brain.
Patient H.M. after the surgery
When he woke up, he couldn’t remember anything within 11 years before the surgery and suffered severe amnesia. He could remember his name, his childhood, family and the stock market crash of 1929. He developed anterograde amnesia, which stopped the ability to form new memories.
Patient H.M. and impact on brain studies
Researchers learned that the temporal lobe must be vital for memory function. Milner also learned that Henry was able to learn motor skills by repeated practice, and that motor learning must be distinct from the system of memory that records new facts, faces and experiences. It also must be located in a different part of the brain that wasn’t affected by the surgery.
London Taxi Drivers
Snapshots were taken of adults’ brains in 3 groups: Those that studied and passed a taxi driver test, those that studied and didn’t pass, and those that didn’t study. The studies showed significant changes in the structure of the posterior hippocampus, as there were greater amounts of grey matter in the region than when they started their training.
London Taxi Drivers impact on brain studies
Professor Maguire said, “The human brain remains ‘plastic’, even in adult life, allowing it to adapt when we learn new tasks.” He also stated that by watching the volunteers as they acquired or failed to acquire the knowledge, we saw how the structure of the hippocampus can change with external stimulation.
Karl Lashley animal studies
Lashley ran tests on different subjects. After these tests, he would damage a part of the subject’s brain and run the tests again, to see what the subject could and couldn’t remember after the damage. He did this in order to understand what part of the brain is responsible for what type of memory.
Sperry animal studies- setup
Sperry cut the corpus callosum of multiple cats, and then had them perform tasks that involved vision. After cutting it, he covered one of the cat’s eyes. He then showed each cat 2 different wooden blocks, one with food under it. He taught the cats to differentiate between those two objects with their paws - pushing the correct wooden block away to get the food.
Sperry animal studies - findings
When he removed the eye patch, the cat could see with both eyes, and he performed the same experiment. The cat hesitated, and then chose both blocks simultaneously. The cat memorised those events separately and could not distinguish between the blocks with both eyes open. He suspected that because of the cut corpus callosum, the hemispheres couldn’t communicate, meaning the cat remembered 2 different scenarios.
Sperry human studies- setup
He showed participants a white screen with a black dot in the middle. The participants were shown a word on each side of the dot for less than a second, and were asked to repeat what they saw. If they saw it with their right eye, they were able to say what they saw, but if their left eye saw it, they couldn’t remember it. He then asked the participants to close their eyes and draw the object with their left hand, as it is the hemisphere that was presented the word.
Sperry human studies- findings
He concluded that the left hemisphere was the language center, and the right hemisphere could only recognize words, not articulate them.
Sperry studies impact on brain studies.
Both hemispheres have two roles. The left can recognise and analyze speech, and the right can recognise words but not articulate them, meaning it could recognise the word, but not know how to pronounce it, so the person couldn’t say what it was.
