Biopsychology Flashcards
Phineas Gage
1848 - working on a rail line
Piece of iron through skull
Change in personality - loss of inhibition and anger
Motor Area
Located in the frontal lobe
Responsible for voluntary movement
Hitzig + Fritsch - motor
Different muscles are coordinated by different areas of the motor cortex
Electrically stimulating motor areas of dogs - muscular contractions in different areas of the body depending on where the probe was inserted
Somatosensory area
Located in the parietal lobe
Recieves incoming sensory information from the skin to produce sensations related to pain
Robertson - somatosensory
Somatosensory area of the brain is highly adaptable, with braille readers having larger areas in the somatosensory area for their fingertips compared to sighted participants
Visual area
Located in the occipital lobe
Recieves and processes visual information
Information from the right hand side is processed in the left hemispere and info from the left is processed in the right hemisphere
Auditory area
Located in the temporal lobe
Analysing and processing acoustic information
Info from the right goes to the left hemisphere and vice versa
Brocas aphasia
impaired ability to produce language
Wernickes aphasia
inability to extract meaning from spoken or written words
Peterson - brain scans
demonstrated Wernickes area was activeduring a listening task and Brocas area during a reading task
Dougherty - OCD
lesioning the cingulate gyrus improved symptoms of OCD
Neuroplasticty
The brains ability to change over time through learning and experience
Synaptic pruning
rarely used connections are deleted and frequently used connections are strengthened
When do synaptic connections peak?
Age 2-3 with around 15,000 per neuron
Maguire - taxi drivers findings
significantly more grey matter in posterior hippocampus than in matched control group
Posterior hippocampus associations
Spatial and navigation skills in humans and animals
Draganski - brain scan of med students
Imaged the brains of medical students 3 months before and after final exams
Learning-induced changes were seen in the posterior hippocampus and the pariettal cortex, presumably as a result of learning
Process of Functional Recovery
- Axonal sprouting - growth of new nerve endings which connect up
- Denervation supersensitivity
- Recruitment of homologous areas on opposite sides of the brain
Negative Plasticity
Brains adaptation to prolonged drug use leads to poorer cognitive function in later life
60-80% of amputees have been known to develop phantom limb syndrome - thought to be due to cortical reorganisation in the somatosensory cortex
Bezzola - Age and Plasticity
40 hours of golf training produced changes in the neural representations of movement in ppts age 40-60
fMRI showed increased activity in motor cortex in novice golfers, suggesting more efficient neural representations after golfing
Seasonal Brain Changes
Suprachiasmatic nucleus regulates sleep/wake cycle
Shrinks in spring, expands in autumn
Most research done on animals
Application of functional recovery
Neurorehabilitation
Understanding axonal growth encourages new therapies
Constraint-induced movement therapy used on stroke patients
Cognitive Reserve - Schenider
Those who spent more time in education had a greater chance of a disability free recovery
Banerjee - Total Anterior Circulation Strokes
5 participants all treated with stem cells - all made a full recovery compared to typical 5%
Hemispheric Lateralisation
The idea that the 2 halves of the brain are functionally differeny and that certain mental processes and behaviours are mainly controlled by on hemisphere
Where is Broca’s area?
left frontal lobe
Where is Wernickes area?
left temporal lobe
What is the function of the right hemisphere in relation to language?
Produce rudimentary words and phrases but contributes emotional context to what is being said
The Synthesiser
What is the function of the left hemisphere in relation to language?
The analyser
How is vision Contralateral and ipsilateral?
Each eye recieves information from both the left and right visual field, allowing visual areas to compare the slightly different perspective from each eye and aids depth perception
What is usually severed in a split-brain operation to reduce epilepsy?
Corpus callosum
What did Sperry do?
devised a system to study how 2 separated hemispheres deal with speech and vision
Sperry - Method
11 ppts - split-brain op
Describe what you see - LVF, RVF
Tactile tests - Objects placed in hand
Drawing task - reproduce picture shown to LVF and RVF
Fink - Hemispheric lateralisation
PET scans identify which areas active during visual processing task
ppts with a connected brain asked to attend to global elements of an image, regions of the RH were much more active
Finer details - LH dominated
Nielson - one brain (opposing evidence for LH analyser and RH synthesiser)
Analysed brain scans from over 1000 people aged 7-29
People use certain areas for different tasks but there is no evidence of a dominant side
Suggests the notion of left or right brained people is wrong
Lesley Rogers - Lateralised Chickens
Lateralised chickens could find food whilst watching for predators, but normal chickens couldn’t
Lateralisation vs plasticity
Lateralisation allows 2 tasks to be performed simultaneously with greater efficiency
Neural Plasticity could be seen as adaptive, following illness or trauma
Split-brain Support - Gazzaniga
Split brain ppts perform better than connected controls on certin tasks, such as spotting the ‘odd one out’
In the normal brain, LH cognitive strategies are ‘watered down’ by the inferior RH
Supports Sperrys findings that the left and right brain are distinct
Sperry - Generalisation Issues
Causal Relationships are hard to establish
Sperrys split-brain epileptic ppts compared to neurotypical group
Unique features could be due to epilepsy rather than the split brain
Sperry - Ethics
Op not performed for purpose of research
Procedures explained, full consent
Trauma of the operation may mean ppts did not fully understand implication
Subject to repeated testing over a lengthy period - causing stress
Sperry - describe what you see findings
RVF - could describe what they see, demonstrating the superiority of the left hemisphere
LVF - could not describe what was shown ‘nothing present
Sperry - tactile tests findings
Right hand - describe verbally what they felt, could identify object, could identify similar object
Left hand - could not describe verbally what they felt but could identify a similar object
Sperry - drawing task findings
RVF - right hand would draw the picture, but was never as clear as the left hand
LVF - Left hand would consistently draw clearer and better pictures
FMRI
Measure brain activity whilst a person is performing a task
Detects radiowaves from changing magnetic fields
Enables researchers to detect which regions of the brain are rich in oxygen and are active
Electroencephalogram - EEG
A record of tiny electrical impulses produced by the brain’s activity
By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain
Event-related Potentials (ERPs)
The electrophysiological response of the brain to a specific sensory, cognitve, or motor event can be isolated through statistical analysis of EEG data
Post-Mortem Examinations
The brain is analysed after death to determine whether certain observed behaviours during the persons lifetime can be linked to structural abnormalities in the brain
FMRI - strengths
Does not rely on the use of radiation
Risk free, non-invasive and straightforward to use
Very high spatial resolution. depicting detail by the mm
FMRI - weaknesses
Expensive
Poor temporal resolution
5s time lag
May not truly represent movemet-moment brai activity
EEG - Strengths
Studing stages of sleep
Diagnosis of neurological disorders
High temporal resolution
Detect brain activity at a resolution of a single millisecond
Event-related potentials - Strengths
Addresses limitations of EEG
Increased specificity to measurement of neural processes
Excellent temporal resolution
Use of ERPs
Measure cognitive functions and deficits such as allocation of attentional resources and the maintenance of working memory
ERP - Limitations
Lack of standardisation in ERP methodology between studies
In order to estalish pure data, background noise and extraneous material must be completely eliminated
Post-Mortem Examination - Strengths
Providing a foundation for early understanding of key processes in the brain
Broca and Wernicke - used post mortem decades before neuroimaging was even a possibility
HM - examined post mortem to identify areas of damage, which could then be associated with his memory deficits
Post-Mortem Examination - Weaknesses
Issue establishing causation
Observed damage may not be linked to deficits undr review but due to unrelated trauma or decay
Ethical Issues - HM lost his memory and could not provide informed consent
Endogenous Pacemakers
The body’s internal biological clock, which regulates biological rhythms
Exogenous Zeitgebers
External cues, helping to regulate internal biological clocks
What regulate biological rhythms?
Endogenous Pacemakers and Exogenous zeitgebers
Suprachiasmatic nucleus
Main endogenous pacemaker
Lies in the hypothalamus
Linkked to areas of the brain linked to sleep and arousal
Where is the suprachiasmatic nucleus located?
Hypothalamus
Hormone which induces sleep
Melatonin
Melanopsin
A protein in the eye, sensitive to light, carries signals to the SCN to set the 24hr cycle