4.Nervous system and Brain Flashcards
describe the brain vs heart debate
Historical debate sounding whether the heart or brain was responsible for central functions including thought, emotion and behaviour
describe briefly the brain hypothesis
thoughts and feelings are rooted in the brain
describe briefly the heart hypothesis
thoughts and feelings are rooted in the heart
Using specific examples, who supported the brain hypothesis
The greeks
-Alcmaeon was the first recorded person to locate the brain as the source of mental processes
-Pythagoras and Plato were also early supporters of the hypothesis
-Galen also posited the brain hypothesis through observation (most famously of pigs)
using specific examples, who supported the heart hypothesis
the egyptians
-empedocles believed that blood was the place for human cognition and thought, especially the blood around the heart’’
-aristotle also proposed that the heart was responsible for all mental functions
who ‘won’ the brain versus heart debate
thanks to empirical scientific evidence we now know that the brain is responsible for our mental functions, feelings and behaviour.
the mind body problem
The mind body problem concerns the questions of whether our mind and body are distinct separate entities or whether they are the same thing
two sides to the mind body problem
dualism
monism
dualism
The mind (non physical) and body (physical) are two distinct things but interact to produce sensations, thoughts, emotions and other conscious experience.
-descartes
monism
suggests that the mind and body are one and the same thing
Brain ablation
Brain ablation involves disabling, destroying or removing selected brain tissue, followed by an assessment of subsequent changes in behaviour
Pierre Flourens
-credited as introducing brain ablation experiments
-discrediting highly specific localisation of function and phrenology
-developed techniques of damaging or removing small areas of brain tissue to observe the effects on behaviour (used rabbits and pigeons)
-found evidence for neural plasticity (animals could eventually recover loss of movement)
Limitations of Pierre Flourens
-Imprecise surgical procedures
-did not provide detailed reports of findings
Karl Lashley
-used brain ablation on rats, monkeys and chimpanzees to find the location of learning and memory in the brain
Identify two key conclusion proposed by Lashley
Mass action
Equipotentiality
Mass action
Large areas of the brain function as a whole for complex functions
Equipotentiality
healthy part of the cortex can take over the function of the injured part (plasticity)
Moniz
-developed lobotomies
-idea that lobotomised chimpanzees became placid compared to the aggression displayed prior the surgery
lobotomy
-A form of psychosurgery to treat mental illness
-Involves scraping away (via the eye) most of the neural connections in the prefrontal cortex
Symptoms of lobotomies
-reduction in cognitive processes and behaviour
-Lack of emotional expression
-Reduction in interest and energy
-dull and lifeless personalities
Electrical stimulation of the brain (ESB) (EBS)
ESB may be done by placing electrodes on or inside a specific place on a persons head. These electrodes then send an electrical signal to that specific area of the brain, thereby stimulating the activity of neurones in that area
Key figures of ESB
-Fritsch and Hitzig
-Wilder Penfield
Penfield- Mapping the brain
-when the cerebral cortex was exposed, Penfield was able to stimulate different areas using an electrode
-Penfield used tiny numbered tags to mark areas of the cortex that he electrically stimulated as he developed his brain ‘map’.
Findings of a split brain patient
-Visual info in the L visual field is sent to the right hemisphere and vice versa
-Split brain patients were able to recognise and name images projected in the R visual field (sent to the left hemisphere-verbal)
-Split brain patients were able to recognise and detect images in the L visual field (sent to right hemisphere-non verbal) but were unable to verbalise what they saw but could draw it with their left hand