Biopsychology Flashcards
localisation of function
spedific parts of the brain deal with different specific functions
what does the frontal lobe control
consiousness, speech production, movement
what does the parietal lobe control
perception
what does the occipital lobe control
vision
what does the temporal lobe control
speech recognition, hearing
Phineus gage case study
- provided evidence for localisation of function
- he suffered an accident in which a pole went through the top of his brain
- before the accident he was friendly
- after the accident he became mean, aggressive, different character
- personality affected
- localised functioning affected
What does the motor cortex do
- voluntary movements
In the frontal lobe in both hemispheres
Arranged logically
Damage to motor cortex may result in loss of fine movements
Stroke
Damage to right hemisphere= left side paralysis
What does the somatosensory cortex do
Recieves sensory info incoming
Outside the body in
Arranged logically
Hands,lips,ears are the most sensory areas
Dedicated to processing sensory info, related to touch
In the parietal lobe in both hemispheres
What does the visual centres do
Colour, shape, movement
Visual processing begins in the retina
In the occipital lobe
Nerve impulses from retina travel to areas of the brain via optic nerves
Each eye has left and right visual field
Info from right visual field to left visual cortex and vice versa
Damage to left hemisphere can produce blindness in right visual field of both eyes
What do the auditory centres do
In temporal lobe on both hemispheres
Begins in cochlea in inner ear
Sound waves converted to nerve impulses
Travel via auditory nerve to auditory cortex
Stop at brain stem where basic decoding happens
Then to thalamus which acts as a relay station and carries out further processing
Last stop is auditory cortex , sound is largely decoded by this stage
In auditory cortex it is recognised and may result in appropriate response
Damage may produce partial hearing loss; more extensive damage; more extensive hearing loss
Karl lashley case study
Used rats- don’t have conscious thoughts
Rats trained to run a maze
Destroyed parts of the brain
Still retained info as after Brian was destroyed they could still run the maze
Concluded that memory did not lie in specific parts of the brain - NOT LOCALISED
What is the Broca’s area
Area of frontal lobe of the brain in the left hemisphere responsible for speech production
Production of articulate speech, clear and fluent
More muscles required to speak
Involved in analysing grammatical structure of sentences
Damage to Broca’s area = brocas aphasia; trouble with speech production
Paul broca
French neurosurgeon
Treated patient called tan
Only could say tan
Studied 8 other patients similar language along with lesions in their left frontal hemisphere
Patient with damage to right hemisphere did not have some problems
Identified existence of a language centre in the back portion of the frontal lobe of the left hemisphere
Believed to be critical for speech production
Wernickes area
In temporal lobe of left hemisphere only
Involved in the interpretation of speech
Referred to has language comprehension centre
Vital for location appropriate words from memory to express meaning
Damage to wernickes area= wernickes aphasia; trouble with speech comprehension, can’t produce meaningful sentences
Kar wernicke
Identified patients who had no problem pronouncing language but severe difficulties understanding it
Turk et al
Patient JW who suffered damage to left hemisphere but developed capacity to speak in right hemisphere, eventually leading to ability to speak about the info presented to either side of the brain
Suggests localisation is not fixed and that the brain can adapt following damage to certain areas
what is hemispheric lateralisation
each side specilaise in something different
what is split brain
corpus callosum severed
what does the left hemisphere control
the right side of the body
speech and language
analytic tasks
what does the right hemisphere control
the left side of the body
visual spatial processing
facial recognition
sperry
- ## 11 split brain patients
.
info from left visual field is processed in the right hemisphere which can see the picture, but as it has no language centre, it cannot respond verbally
the LH which does have a language centre, does not receive the information about the picturetherefore cannot say it has seen it
what is plasticity
brains ability to change and adapt because of experience
- during infancy brain experience rapid growth of number of synaptic connection it has
- as we age rarely used connection are deleted and frequently sued connections are strengthened
neural pathways
each time you learn something new, synaptic connections and neural pathways are formed
- less you use a neural pathway the weaker it gets, eventually gets deleted (forgotten)- synaptic pruning
what is synaptic pruning
when the neural pathway gets deleted as it is not revisited so gets weaker
what is functional recovery
the transfer of functions from a damaged area of the brain after trauma to other un damaged areas
- it can do this through a process called neural unmasking
- increased brain stimulation such as using physiotherapy can also enhance recovery
what is neural unmasking
where dormant synapses (which have not received enough input to be active) open connections to compensate for a nearby damaged area of the brain
what happens after a stroke
it damages/destroys brain cells
the brain can retire itself over time so some level of function can be regained
if a part of the brain has been damaged /destroyed other parts of the brain can take over functions that were lost
neurone next to the damaged brain areas can form new circuits
what is axonal sprouting
new nerve endings grow and connect with in damaged areas
- creates new blood vessels and pathways around the damaged area
what is reformation of blood vessels
- with neural pathways supporting and reinforcing these new connections with blood vessels
what is recruitment of homologous areas
areas on opposite hemisphere to do specific tasks
e..g. if broca’s area was damaged then an area on the right might take over
what is denervation super sensitivity
axons with a similar function to the damaged ones are more aroused and more sensitive to input
- loss of nerve supply to a particular area of the body results in an increase in sensitivity of the remaining nerves in that area
- nerves that used to supply the limb are no longer present but the remaining nerves in the area become hypersensitive, causing pain
- phantom limb occurs when rewiring takes place in the brain but it overcompensates in the somatosensory cortex where signals for pain are
- as a result the person feels pain in a limb no longer present
maguire et al (2000)
- brain scans of 16 london taxi drivers
showed a large posterior hippocampus- region of the brain that supports 2d spatial processing - posterior hippocampus was largest in taxi drivers with more than 40 years of experience navigating streets of london
research into plasticity - elbert et al
- violinist relies on extraordinary finger dexterity in their left hand. much less dexterity required in the fingers of the right hand which is responsible for bowing
- brain scans of somatosensory cortex in violinists reveal an unusually large region devoted to the fingers of the left hand - much larger than the region that supports finger movement in the right hand.
asymmetry suggests the brain has responded to the demands placed upon it
brain also adapts by recruiting neurone to help support finger control in the left hand
research into plasticity - danelli (2013)
- italian boy et who had most of his left hemisphere removed at age 2 1/2 to remove a tumour
- with intensive therapy eb’s right hemisphere was able to take over left hemisphere functions such as language and speech due to eb’s maximal plasticity as he was young
how does age affect plasticity
capacity for neural regeneration is much greater in children than in adults meaning that neural regeneration is less effective in older brains
explains why adults find change more demanding than young people do
how does gender affect functional recovery
research shown women recover quicker than men
- willingness
how does education affect functional recovery
if you stay in education longer more likely to recover better
what is a post mortem
- invasive method
- examination of a corpse in order to determine the cause of death
strengths of post mortem
brain examined to try and correlate structural abnormalities/ damage to behaviour
weaknesses of post mortem
- lack validity due to small sample, individual patients
- neural changes may be due to death
paul broca post morreo on tan
- investigated location of speech production in the brain
in post mortem examination broca discovered tan had a lesion in the left cerebral hemisphere caused by syphilis
this area of the brain became known as the brocas area
what is FMRI
- functional magnetic resonance imagine
- non invasive
- 3d scans using magnetic and radio waves
- they measure brain activity tracking blood flow
- measures change in energy released by haemoglobin reflecting activity of the brain (oxygen consumption)
- person lies in large cylinder magnet and radio waves sent through the body affecting body’s atoms
- moving pic of the brain is produced
- time lapse of 5 seconds so not totally live
strengths of FMRI
- captures dynamic brain acitivity as opposed to MRI/Post mortem which only show physiology of brain
- good spatial resolution
weaknesses of FMRI
- expensive
- interpretation difficult and affected by temporal resolution due to 5 sec delay
what is EEG
- non invasive
- electroencephalogram
- brain cells send messages to each other they produce tiny electrical signals
- electrodes placed onto the scalp using sticky substance
- these electrodes pick up the electrical signals/neuronal activity from the brain and send them to an EEG machine, which will record the signals on a computer screen which clinicians then monitor
strengths of EEG
- cheaper than FMR
- non invasive so ethically good
- good temporal resolution
weaknesses of EEG
- poor spatial resolution
what is ERPs
- event related potentials
- non invasive
- measuring brains response to stimulus through alanalysis of EEG data in response to a stimulus
- using average of original EEG recording researchers can filter out all the other brain activity apart from what they are interested in
- sensory ERPs occur within 100 millisecond
- cognitive ERPs are over 100 millisecs
strengths of ERPs
- cheaper than FMRI
- good temporal resolution
weaknesses of ERP’s
poor spatial resolution
