Physiology, Psychophysics and the Science of Mind Flashcards
what was trephining
Stone Age humans bored or chiseled holes into skulls of living individuals, perhaps to release supposed evil spirits or as a cure for headaches or bizarre behaviours, or as punishment
describe early representations of trephining
Bosch did a painting called “the extraction of the stone of madness” which is usually interpreted as an allegory for foolishness/stupidity –> metaphor for how insanity might be cured by removing the stone of madness
when did humans understand that the brain was an organ of importance
there is evidence that early homonids knew head injuries could cause disabilities or death –> these injuries were inflicted intentionally on animal prey and sometimes other homonids
who is credited with the recognition that the brain is the organ of intelligence
Hippocrates
when to anatomical treatises (written work) on the brain date to
anatomical treatises on the brain and sensory organs (particularly the eyes), including diagrams based on dissections, are more than 2500 years old
when was a productive time for advances in brain anatomy
the Renaissance
what did Leonardo da Vinci do during the Renaissance
he dissected more than 300 cadavers (many of whom were executed criminals) and made detailed drawings of the brain –> incredible accuracy in drawings that hadn’t been seen before
who was Andreas Vesalius
he made significant advances in neuroanatomy and described the human brain in great detail with words and images –> published his drawings, unlike da Vinci
what were some important milestones during the Renaissance
- discovery of cerebrospinal fluid
- differentiation between white and gray matter in the cortex
- naming of brain areas (including the pons and hippocampus)
- discovery that the image on the retina was inverted
when was the microscope invented and by whom
- seventeenth century –> Anton van Leeuwenhoek
- created lenses of sufficient magnification to see neurons
describe Leeuwenhoek’s contributions to neuroscience
he created the microscope with lenses sufficient enough to see the “invisible” world of unicellular organisms in a pond of water –> also sufficient enough to see neurons
describe Leeuwenhoek’s research on the eye
he used the microscope to study the tissues of the eye, especially the retina –> might of been the first to see photoreceptors for vision (rods and cones)
when did understanding of brain anatomy develop
there was some better understanding with the use of the microscope and better dissection/preservation techniques in the 17th c., but more significant understanding of the areas of the brain and nervous system required the technological advances of the 19th c.
what inspired developing neurological work
there were medical implications, but also philosophical implications (speculation about the nature of the mind and senses)
what did psychophysics seek to measure
the relationship between events in the physical world and the psychological perception of those events
what is an fMRI
a device that provides images of blood flow or other metabolic changes in an intact, functioning brain in a conscious human subject –> allows the comparison of brain activity with ongoing mental activity (e.g. recording images of the brain’s functioning while the subject is solving mental arithmetic problems)
what were some of the key questions in 19th c. neurophysiology that were important to research in psychology (3 questions)
- cortical localization of function –> do different areas of the brain serve different functions, or are they non-specific
- specificity of the nerves –> do certain nerves carry information of only one kind?
- speed of nerve conduction –> how fast does information travel
describe the question of cortical localization of function
do difference areas of the brain, marked by different tissue structure, texture, density and cellular composition, serve different functions? Or are the functions of the brain nonspecific and spread across the cortex
describe the question of specificity of the nerves
might certain nerves carry information of only one kind, or did nerves carry all kinds of information
what initiated the discussion on cortical localization of function
Gall’s work in anatomy and phrenology (crainoscopy) –> known for his work on the cranial nerves, brain stem anatomy and differentiations of neural functioning of white and gray matter in the cortex
how did Gall’s ideas on phrenology begin
he claimed that his ideas on it began when he was 9 years old and noticed a classmate who showed good verbal memory and had bulging eyes –> noticed in other people a correlation between bulging eyes and verbal memory, and assumed that the growth of the frontal lobes was excessive in these individuals, causing their eyes to bulge
what did Gall notice in his patients during his work as an anatomist
he noticed clinical cases where individuals had suffered head wounds and consequently showed certain personality changes or intellectual deficits as a result
describe Gall’s system of phrenology
he identified 27 different faculties that resided on the cerebral cortex
why was phrenology accepted by the medical community for a decade
- there was already work on nerves showing specificity of function, so it made sense to them that the cortex would also show specificity
- neuroanatomical studies by Gall himself showed anatomical differences across the cortex, so why not functional differences as well
describe Flourens’s response to Gall’s phrenology
Flourens was a French neuropsychologist who set out to test the claims of phrenologists using animals (because gall argued that 19/27 faculties could be found in animals) –> removed brain tissue from these areas and then observed losses of function
when was phrenology rejected by the medical community in North America and Europe
the 1860s
describe what Flourens found in his loss of function experiments in animals
- Gall claimed the cerebellum controlled sexual behaviour, so Flourens lesioned this area and observed deficits in motor behaviour but not sexual activity
- As he made larger and larger lesions in the brain, he noted loss of function across many different behaviours –> concluded that behaviour control was spread widely across the brain and was not localized (this also was not correct)
what did Bouillaud contribute to the study on cortical localization
he made his case for functional locations in the brain, emphasizing an anterior portion of the cortex responsible for speech –> these claims were supported by Aubertin (his son-in-law)
describe Aubertin’s contribution to cortical localization of function
- 1861 meeting of Anthropology –> made a case for a speech centre and noted how it was supported by his own clinical research and would be solidified through autopsies on patients with loss of speech
- Broca attended this meeting
describe the work of Broca
- he encountered a patient in surgery who was suffering from cellulitis (skin disorder causing tissue inflammation) and couldn’t speak other than repeating the word “tan” but could still understand everything being said
- a few years earlier, the patient had also experienced gradual paralysis in his right arm/leg
- Broca performed an autopsy immediately after he died and suspected damage on the left side of the brain (because of the right side paralysis, and contralateral projection was already discovered)
what did Broca discover in his patient “tan”
- there was a hole in the cortex of the left frontal lobe –> tissue was deprived of blood supply for 20 years and died, causing the loss of speech –> tissue had dissolved and was carried away in the cerebrospinal fluid
- paralysis resulted from lesions elsewhere on the same side of the brain
- determined this area of frontal lobe was important for language
how did Broca increase the support for his claims that a particular area in the frontal lobe was important for language
he acquired a dozen more clinical cases demonstrating frontal lobe damage in the left cortical hemisphere (in around the same area as Tan)
what is Broca’s area
associated with the production of speech (expressive aphasia) but not the understanding of speech (receptive aphasia)
what is Wernike’s area
associated with the understanding of language (receptive aphasia) –> mediated in the left temporal-parietal cortex
what contributions did Hitzig & Fritsch make
they performed electrical stimulation studies of nerves (based on pre-existing understanding of electrical nerve impulses) in exposed cortices of dogs –> showed that a number of different voluntary movements occurred due to stimulation (e.g. movement of the front or hind leg, facial movements)
what did Broca’s work have in common with Hitzig & Fritsch’s work
both of the studies were reliably reproduced and showed evidence in support of localization of function (stimulating an area causes a specific movement, lesioning an area causes a specific loss of function)
who was the first to electrically stimulate a living human brain
- some evidence that it could have been Hitzig (but this is controversial)
- Barthalow is better accepted as the first to do this –> applied electrical current to the brain of a patient and reported movement in arms and legs was contralateral to stimulation of the brain
who was Ferrier
neurologist who published a book based on intensive studies on animals (particularly monkeys) –> used precise and systematic techniques, and produced highly detailed mapping of sensory and motor functions in the brain