Biopsychology L5-12 Flashcards
Which hemisphere controls the left side of the body?
Right
Which hemisphere controls the right side of the body?
Left
Describe the auditory pathway. Where is the cortex located?
Located in the temporal lobe
- Cochlea (sound waves converted to electrical impulses)
- Brain stem (basic decoding takes place)
- Thalamus (further processing)
- Auditory cortex
Describe the visual pathway. Where is the cortex located?
Located in the occipital lobe
- Retina (light strikes photoreceptors)
- Thalamus (via optic nerve)
- Visual cortex
What is the motor cortex responsible for? Where is it located?
Responsible for voluntary motor movements - different parts control different body parts.
Located in frontal lobe along the precentral gyrus
What is the somatosensory cortex responsible for? Where is it located?
Responsible for detecting sensory events to produce sensations localised to certain parts of the body.
Located in parietal lobe along postcentral gyrus
What is the Broca’s Area responsible for? Where is it located?
Responsible for producing speech. Fedorenko et al (2012) found two regions - one involved in language and the other in demanding cognitive tasks.
Located in ONLY THE LEFT frontal lobe.
What is the Wernicke’s Area responsible for? Where is it located?
Responsible for receiving/understanding speech.
Located in ONLY THE LEFT temporal lobe.
What is expressive aphasia? What is the cause?
Inability to produce speech, due to lesions to the Broca’s Area
What is receptive aphasia? What is the cause?
Inability to understand and respond accordingly to speech, due to lesions to the Wernicke’s Area
State 3 negative evaluation points for localisation of function?
- Dronkers et al (2007) re-examined brains of Broca’s patients - found several areas of brain damaged, concluded lesions to Broca’s area causes temporary speech disruption
- Bavelier et al (1997) found individual differences in activated brain areas when silently reading. Activity observed in temporal lobe, left frontal lobe, and occipital lobe
- Dejerine (1892) found patient who couldn’t read due to damage to the visual cortex and Wernicke’s area - communication between brain areas may be more important than specific areas
Define localisation of function.
The principle that specific functions have specific locations within the brain.
Define lateralisation of function.
The idea that the two different hemispheres of the brain have different specialisations
What is the left hemisphere dominant at?
Language and speech
What is the right hemisphere dominant at?
Visual-motor tasks and facial recognition
What is the corpus callosum?
Bundle of nerve fibres that connects the hemispheres
State 2 positives about lateralisation of function.
- Increases neural processing capacity. Multi-tasking hemispheres (one does one task, one does the other). Rogers et al (2004) found lateralisation in chickens linked to ability to multi-task
- Architects and math experts tend to have superior right hemispheric skills to left hemispheric skills
State 2 negatives about lateralisation of function.
- Doesn’t remain the same during a lifetime. Szaflarski et al (2006) found language become more lateralised to the left until 25yrs old, then lateralisation decreased
- JW developed capacity to speak out of right hemisphere - can speak on info given to right or left hemisphere (Turk et al 2002)
What is split-brain research?
Research into patients that have had their corpus callosum cut to prevent violent epileptic seizures
Describe Sperry and Gazzaniga’s 1968 research study.
1) Patients stare at dot at centre of screen
2) Information presented to either left or right visual field
3) Patient response through left or right hand, or verbally
What was found in Sperry and Gazzaniga’s resarch study?
If information enters the left visual field (right hemisphere), the patient won’t be able to say it because only the left hemisphere has language centres. The patient can draw the item, but only with their left hand (controlled by right hemisphere)
State 3 negatives of split-brain research.
- Hard to generalise study - some only use 3 patients
- Disconnection between hemispheres is greater in some patients than others - having drug therapy for epilepsy for longer could affect brain
- Not valid to compare previously epileptic patients with control group with no epileptic history
State 2 positives of split-brain research
- Gives greater understanding of differing functions of brain sections
- Doesn’t have much effect on daily life of patient, but removes their painful epileptic seizures
Define brain plasticity.
The brain’s ability to change and adapt as a result of experience. Plays an important role in development and behaviour.
What are the three influencers of plasticity?
- Life experience
- Meditation
- Video games
How are life experiences and plasticity related?
Frequently used nerve pathways develop stronger connections, rarely used pathways die - brain adapts to change.
What evidence is there to support the relationship between life experience and plasticity?
Boyke et al (2008) taught 60yr olds to juggle - increased grey matter in visual cortex
How are video games and plasticity related?
Kuhn et al (2014) compared control group to group that played Super Mario for 30mins/day for 2 months. Found increased grey matter in visual cortex, hippocampus and cerebellum. Concluded video games increases synaptic connections in brain involved in spatial navigation, strategic planning, working memory and motor performance.
What areas of the brain are affected by video games?
Cerebellum, Hippocampus, Visual Cortex
How is meditation and plasticity related?
Davidson et al (2004) comapred 8 Tibetan monks with 10 students with no experience of meditation. Both groups meditated for short periods. Greater gamma wave activity in monks before meditating
What is the role of gamma waves in the brain?
Co-ordinate neural activity
State 2 positive points on plasticity?
- Kemperman et al (1998) found more new neurons in brains of rats in complex environments than lab cages. Increase prominent in hippocampus (issue of generalisation)
- Maguire et al (2000) measured grey matter of London taxi drivers with MRI scan - found larger hippocampus (forming memories and navigation) than control group
Define functional recovery.
When neurones are damaged the brain re-wires itself over time. Other parts of the brain take over the functioning of the damaged part(s).
What are dormant synapses?
Synaptic connections that exist, but their function’s been blocked.
What is neuronal unmasking?
The process of increasing neural input to dormant synapses to open connections to areas that aren’t usually active - occurs when areas are damaged, can lead to development of brain structures
What are stem cells?
Unspecialised cells that have the potential to differentiate into any cell type.
What are the hopes for stem cells in research?
- Implanted into brain to replace dead/dying cells
- Transported stem cells secrete growth factors to ‘rescue’ damaged cells
- Transported stem cells form neural network linking from damaged site to functioning brain site
State 2 positives of functional recovery.
- Tajiri et al (2013) studied rats with traumatic brain injuries - one group received stem cell transplants into damaged brain area, 3 months later showed development of neuron-like cells. (ethical issues - caused injury, can’t generalise)
- Studies show abilities learnt in childhood can be modified in adulthood, but takes intensive retraining
State 2 negatives of functional recovery.
- Elbert et al (2001) concluded capacity for neural reorganisation after brain injury is greater in children
- Schneider et al (2014) found patients with college education are 7x more likely to be disability-free a year after brain injury than those who didn’t finish secondary school. Concluded neural reserve could be a factor in recovery
Describe the technique of a post-mortem. What is its use?
- Person who displays interesting behaviour dies
- Brain analysed for abnormalities
It’s used to discover links between brain structures and psychiatric disorders.
State 2 strengths and 2 weaknesses of post-mortems.
Strengths:
- Allows for more detailed examination of anatomical and neurochemical aspects of the brain than scans
- Provides greater understanding of rare disorders
Weakness:
- Only observes what’s happening on the surface
- Death circumstances could affect the brain, e.g. disease, age of death, time since death
Describe the technique of Functional Magnetic Resonance Imaging (fMRI). What is its use?
- Patient placed in MRI scanner
- Blood flow of brain monitored when carrying out certain tasks
It’s used to measure brain activity in relation to a task