1.2 the role of the brain in mental processes and behaviour (c4) Flashcards
brain vs heart debate
is our brain or heart the source of our thoughts, feelings and behaviours?
mind-body problem?
are our mind & body distinct? separate entities or are they one? is the mind part of the body or is the body part of the mind?
Descartes (French philosopher)- Dualism
Mind and body are 2 different things- mind is non physical, spiritual entity whereas soul whereas body is physical- PINEAL GLAND SEAT OF THE SOUL
what is phrenology?
a pseudoscience primarily focused on measurements of the human skull, based on the concept that the brain is the organ of the mind, and that certain brain areas have localised specific functions
Franz Gall in 1786, popular in 19th century
what are the 3 types of first brain experiments?
- Brain ablation experiments
- Electrical stimulation of brain (ESB)
- Split brain experiments
brain ablation experiments
- involves disabling, destroying or removing selected brain tissue followed by an assessment of subsequent changes in behaviour
- often done surgically with scalpel cuts
- sometimes called lesioning
- irreversible
- unethical BUT may be used for brain tumour removal
who was pierre flourens?
a French psychologist (1794-1867)
what did pierre flourens do?
he worked mainly with rabbits and pigeons by damaging or removing small areas of brain tissue to observe the effects on behaviour
found injury to one part of brain stem caused animals to stop breathing so he assumed the brain stem was responsible for respiration
also found animals could eventually recover this function
FIRST EVIDENCE OF NEUROPLASTICITY
used this finding to argue a “holistic” view of brain function- cortex worked as a whole
believed that recovery from injury to cortical brain tissue was possible because the remaining cortex could do the same things that the missing cortex had done, so it could take over.
Karl Lashley- location of memory and learning
rats, monkeys and chimpanzees were taught various tasks and then bits of their cortical tissue were removed with the goal of producing amnesia
Lashley failed to produce amnesia and concluded that learning and memory were located throughout the brain rather than in a single place
how can electrical activity in the brain be stimulated/detected?
by using an electrode- a small, electrified fine wire (or disc) that can be inserted into or placed onto a specific area of the brain
it is assumed that if electrical stimulation of a specific brain area initiates a response…
then that area controls or is involved in the response
who is Gustav Fritsch and Edward Hitzig?
Germany physicians from the 1800s
what did Fritsch and Hitzig do
used recent improvements in the control of electricity to stimulate what is now called the motor cortex of a dog
what did Fritsch and Hitzig discover
found 5 sites that, when stimulated, triggered distinctive movements on the opposite site of the body
successful ESB, experiments demonstrated contralateral function of limb movement
what did Wilber Penfield do
used ESB to map the cerebral cortex with his epileptic patients as research participants
When cerebral cortex was e xposed, Penfield was able to stimulate different areas using an electrode and to ask his patients to report their experiences
who conducted the split brain experiments
American neuropsychologist Roger Sperry (1913-1994)
what did Sperry do
studied patients who had undergone splitbrain surgery and demonstrated that the brain’s two cerebral hemispheres specialise in different tasks
what is splitbrain surgery
cutting the corpus callosum
what are the 2 types of neuroimaging techniques
structural, functional
what is neuroimaging
a modern technique that captures a pic of the brain
what does CT stand for
computerised tomography
what does CAT stand for
computerised axial tomography
is CT same as CAT
yes
advantages of CT/CAT scans?
safe
cost effective
identifies precise locations
limitations of CT/CAT scans?
no info of brain activity during cognitive tasks
how do CT/CAT scans work?
patients are given a contrast to highlight the brain’s blood vessels to find the location and size of a tumour, damage (caused by stroke or injury) or brain abnormalities in conditions such as depression, schizophrenia, alzheimers
how do CT/CAT scans work?
patients are given a contrast to highlight the brain’s blood vessels to find the location and size of a tumour, damage (caused by stroke or injury) or brain abnormalities in conditions such as depression, schizophrenia, alzheimers
what does MRI stand for
magnetic resonance imaging
advantages of MRI
detailed computer enhanced colour
limitations of MRI
expensive
cannot be used on people with internal metal devices like pace makers
why might MRI be better than CT
MRI is more sensitive, clearer and more detailed, full colour
how do MRI scans work
uses harmless magnetic fields to vibrate atoms in the brain’s neurones and generate a computer image of brain
taken with long, metal cylinder in which the participants must lay very still
are MRIs structural or functional
structural
are CTs structural or functional
structural
are PET scans structural or functional
functional
what does PET stand for
positron emission tomography
how do PET scans work
provides images of “working brain” by tracking a glucose solution containing a short-lived radioactive tracer
this is injected into the bloodstream before scanning
when it reaches the brain, the amount used during a given task is recorded
it is assumed that brain areas that require increased blood flow have increased neuronal activity
advantages of PET scans
provides info abt function and corresponding location of particular areas of brain
limitations of PET scans
expensive to run
what does fMRI stand for
functional magnetic resonance imaging
are fMRI scans structural or functional
functional
how do fMRI scans work
detects and records brain activity by measuring oxygen consumption across the brain
takes numerous pics of brain in rapid succession and can therefore detect brain changes as they occur from moment to moment
images of brain structures and activity are more highly detailed and more precise
advantages of fMRI scans
high quality image of brain
allows researchers to view blood flow
limitations of fMRI scans
very loud (earplugs required)
unable to detect which brain receptors are being activated by particular neurotransmitters
3 main functions of nervous system?
receive info, process info, coordinate response to info
2 parts of PNS?
autonomic, somatic
function of autonomic nervous system
communicates w internal organs and glands
function of somatic nervous system
communicates w sense organs and voluntary muscles
2 parts of autonomic nervous system?
sympathetic, parasympathetic
meaning of sympathetic?
arousing
meaning of parasympathetic?
calming
3 parts of brain?
forebrain, midbrain, hindbrain
hindbrain consists of
pons, medulla, reticular formation, cerebellum
cerebellum function?
coordinates fine muscle movements
regulates posture + balance
what happens when the cerebellum is damaged?
makes it difficult to coordinate muscle control and causes problems w balance
function of medulla?
controls vital bodily functions such as swallowing, breathing, heart rate
some parts involved in sensations like touch, pressure, vibration
what happens when medulla is damaged
e.g. blow to back of head is often fatal
what are pons
small bundle of neural tissue
function of pons?
involved in sleep, dreaming, arousal from sleep (waking)
controls breathing and coordination of some muscle movements
bridge between the cerebral cortex and cerebellum and between medulla and midbrain
what does RAS stand for
reticular activating system
whats in midbrain?
reticular formation
direction of pathways of RAS
both ascending and descending pathways
function of reticular formation?
screens incoming info so as not to overload brain
alerts higher brain centres to important info
helps maintain consciousness
regulates arousal and muscle tone (tension)
how does RAS regulate arousal
in response to feedback from upper and lower brain areas
structures in forebrain?
hypothalamus, thalamus, cerebrum
function of forebrain?
regulates complex cognitive processes such as thinking, learning, memory and perception, emotion, personality
function of hypothalamus
maintains body’s internal environment- homeostasis
regulates release of hormones from various glands in body associated w basic biological needs such as hunger, thirst, sleep
function of thalamus
almost all sensory and moto info going to and from the cerebral cortex is processed through the thalamus
function of cerebrum
responsible for almost everything we consciously think, feel and do
what is the cerebral cortex
outer layer of brain
are cerebral hemispheres alike
yes they look similar and have many of the same functions BUT they are specialised
where does information from the right side of the body go to
the left hemisphere
where does information from the left side of the body go to
the right hemisphere
function of frontal lobe
regulation of emotions and expression of emotional reactions and aspects of personality such as initiating appropriate and inhibiting inappropriate behaviour
plans and initiates voluntary bodily movements
plans required motor sequence then sends the instructions to the premotor cortex towards the back of the frontal lobe
function of prefrontal cortex
sophisticated mental abilities such as reasoning, problem solving, decision making, symbolic thinking
function of primary motor cortex
initiates and controls voluntary movements through its control of skeletal muscles
function of Brocas area
production of articulate speech (clear and fluent)
how did lobotomies affect patients
decreases patients’ emotional responsiveness
many became emotionally docile, extremely and consistently calm
easier to manage in psychiatric hospitals
left patients disconnected from social surroundings and affected the rest of their cognitive functions
function of parietal lobe
receives and processes bodily (somatosensory) info (including touch, temp - skin-, info abt muscle movement and the body’s position from muscles tendons and joints)
function of primary somatosensory c ortex
receives and processes sensory info from skin and body + other parts (e.g. lips)
function of occipital lobe
vision
what happens when occipital lobe is damaged
can produce serious visual impairments even if eyes and other neural connections r normal
function of primary visual cortex
major destination of visual info from eyes
info comes to primary visual cortex from visual sensory recpetors located on the retina at the back of each eye
function of temporal lobe
involved w auditory perception and also plays an important role in
- memory
- our ability to identify objects and recognise faces
- emotional responses to sensory info and memories
diff areas specialised to register and respond to diff features of sound
function of wernicke’s area
involved in speech production but has a crucial role in the comprehension of speech
more specifically in interpreting the sounds of human speech
what happens when you hear a word
the primary auditory cortex of left temporal lobe processes the auditory info, but u cannot understand the word until the information has been processed by Wernicke’s area
what are the two principles lashley established
mass action and equipotentiality
what is mass action
the idea that the large areas of the brain function as a whole in complex functions and that if a part is destroyed then loss of function will depend on the amount of cortex that is destroyed
what is equipotentiality
the idea that any healthy part of the cortex can take over the function of an injured part
In many American states, a police officer may ask a driver to walk a straight line as a simple and quick measure of a potential drink-driving offence. An intoxicated driver will usually be unable to consistently remain on the line or walk precisely, smoothly and steadily. Considering the driver’s impairment, which brain structure is likely to be most affected by the alcohol?
cerebellum
Why is the thalamus described as a ‘relay station’?
Filters incoming sensory input (except sounds) then directs to relevant sensory cortical areas; receives messages from cortical areas and directs to lower brain structures.
What other brain structure consistently relays information?
reticular formation (incl. the RAS)
In terms of structure and function, how does the cerebrum in humans differ from that of other animals?
structure: has hemispheres and more cortex than in all other animals
function: more sophisticated/higher order functions in humans, i.e. cerebral cortex that covers the cerebrum
List three key functions that the cerebral hemispheres have in common.
motor functions involving initiation of voluntary movements for the opposite side of the body
sensory functions involving reception and processing sensory information from the opposite side of the body
integration (‘association’) of information from different hemispheres and other areas to perform more complex functions dependent on information from different areas e.g. planning, problem-solving, decision making
