BioPsychology AO1 Flashcards
(15 cards)
Localisation of Function… define, support
Localisation of function refers to the theory that different areas of the brain are responsible for different behaviours and cognitive processes. Damage to specific areas results in a loss of the associated function. Early support came from Broca and Wernicke in the 19th century. Broca found that damage to the left frontal lobe (Broca’s area) impaired speech production (e.g., patient “Tan”), while Wernicke identified a separate area in the left temporal lobe (Wernicke’s area) responsible for language comprehension — patients could speak fluently but their speech was meaningless. These discoveries supported the idea that language functions are lateralised to the left hemisphere.
Define, state where it’s located, and what the function is of:
- Motor cortex
- Somatosensory cortex
- Visual cortex
The motor cortex is located in the frontal lobe, just in front of the central sulcus, and controls voluntary movement. It is contralateral — the left hemisphere controls the right side of the body, and vice versa.
The somatosensory cortex, in the parietal lobe, just behind the central sulcus, processes sensory input like touch and temperature.
The visual cortex is found in the occipital lobe and processes visual information, with each hemisphere receiving input from the opposite visual field.
Define, state function of, and location of:
- Auditory cortex
- Broca’s area
- Wernicke’s area
The auditory cortex, located in the temporal lobe, is involved in processing auditory information, including speech.
Broca’s area (left frontal lobe) is responsible for speech production — damage leads to Broca’s aphasia (slow, non-fluent speech).
Wernicke’s area, in the left temporal lobe, is responsible for language comprehension — damage leads to fluent but meaningless speech and neologisms. These areas are typically lateralised to the left hemisphere, particularly for language.
Define Hemispheric Lateralisation… difference between left and right hemispheres, what functions are both localised and lateralised?
Hemispheric lateralisation refers to the idea that the two hemispheres of the brain have different specialisations. For example, the left hemisphere is primarily responsible for language production and comprehension, while the right hemisphere is more involved in visuospatial processing, emotion recognition, and face recognition. Unlike localisation of function (which refers to specific areas within a hemisphere), lateralisation refers to entire hemispheres having dominant roles in particular functions.
Some functions are both localised and lateralised, such as Broca’s and Wernicke’s areas, which are localised to specific regions and also lateralised to the left hemisphere in most people. The brain is also contralateral in its control — the left hemisphere controls the right side of the body and vice versa.
🧪 Split-Brain Research (Sperry & Gazzaniga) – AO1
To investigate the extent to which functions are lateralised across hemispheres by studying split-brain patients (people with a severed corpus callosum).
Method: Studied 11 patients who had undergone commissurotomy (removal of corpus callosum). Visual stimuli were presented to either the left visual field (LVF) or right visual field (RVF) using a tachistoscope. Due to the severed corpus callosum, the information could not be shared between hemispheres.
Tasks included:
1. Describe what they saw in each visual field.
2. Draw what they saw (visuospatial).
3. Select objects related to the stimulus (tactile recognition).
4. Face matching and recognising composite faces.
Results:
* Left hemisphere (RVF): Could describe objects verbally but struggled with facial recognition.
* Right hemisphere (LVF): Could select or draw objects but could not name them.
* Face tasks showed that the right hemisphere excels at facial recognition and emotional processing.
* An interesting finding was emotional response (e.g., laughter) from right hemisphere stimuli, even when patients couldn’t verbalise why.
Define Brain Plasticity, define synaptic pruning
What research supports this?
Brain plasticity refers to the brain’s lifelong ability to adapt structurally and functionally in response to learning, experience, or injury. During infancy, synaptic density rapidly increases (around 15,000 connections per neuron at ages 2–3), but as we age, synaptic pruning eliminates weaker or unused connections, enhancing efficiency.
Research supports adult brain plasticity. Maguire et al. (2000) found increased grey matter in the posterior hippocampus of London taxi drivers—linked to navigational skills—compared to controls. Draganski et al. (2006) observed increased grey matter in the hippocampus and parietal cortex of medical students after studying for exams, suggesting learning reshapes neural structures.
Define Functional Recovery as form of plasticity
What are the 4 mechanisms involved?
Functional recovery is a form of plasticity that occurs after brain trauma (e.g., stroke). Unaffected areas of the brain adapt by reorganising and taking over functions of damaged regions. This can happen naturally or be enhanced with therapy.
Mechanisms involved include:
Axonal sprouting – growth of new nerve endings connecting with undamaged neurons.
Recruitment of homologous areas – equivalent areas in the opposite hemisphere take over (e.g., right Broca’s area compensating for damage in the left).
Denervation supersensitivity – surviving axons become more responsive.
Neuronal unmasking – activation of previously dormant synapses.
Plasticity is influenced by age and cognitive reserve (e.g., higher education may enhance recovery outcomes).
Define EEG, and what is its function?
🧠 EEG (Electroencephalogram)
EEG measures electrical activity in the brain using electrodes placed on the scalp. It records brainwave patterns generated by millions of neurons, helping identify arrhythmic activity linked to epilepsy, sleep disorders, or brain injuries. It provides high temporal resolution, making it useful for tracking brain states in real time, although it lacks spatial specificity.
Define ERP and what is its function?
🧠 ERP (Event-Related Potential)
ERPs use statistical filtering to isolate brain responses to specific stimuli from general EEG activity. After repeated stimulus exposure, only consistent neural responses are averaged into the final ERP signal. This allows researchers to study attention, perception, or decision-making with high temporal resolution, but precise spatial localisation remains difficult.
Define FmRi and what its function is
🧠 fMRI (Functional Magnetic Resonance Imaging)
fMRI indirectly measures brain activity by detecting changes in blood oxygenation and flow — the hemodynamic response. It produces 3D activation maps showing which brain areas are active during tasks, such as looking at images. fMRI has excellent spatial resolution, making it ideal for localising function, though it has poor temporal resolution and is expensive.
What are post-mortem examinations and why are they undertaken?
🧠 Post-Mortem Examinations
Post-mortems involve analysing the brain after death, often from individuals with rare disorders. Structural abnormalities are identified and linked to observed behaviours or cognitive deficits. This allows detailed examination of deep brain structures, which can’t be studied with scans. However, causation is hard to determine, and retrospective analysis limits usefulness for living cognition.
What are Circadian Rhythms and what role does the SCN have?
Circadian rhythms are biological cycles lasting around 24 hours and help optimise behaviour to day-night cycles (e.g., sleep-wake cycle, body temp). The suprachiasmatic nucleus (SCN) in the hypothalamus is the master endogenous pacemaker regulating these rhythms.
The SCN signals the pineal gland to release melatonin in response to darkness, making us feel sleepy; melatonin levels drop with daylight. The SCN is “free-running” (around 24–25 hours) but must be reset by exogenous zeitgebers like light—this resetting is called photoentrainment.
Light is detected by the retina and transmitted via the optic nerve to the SCN, even when eyes are closed (via optic chiasm).
For Circadian Rhythms what did the following find?
- Siffre
- Aschoff and Wever
- Folklard
- Morgan
Research support:
* Siffre found natural circadian rhythm was around 25 hours in a cave with no external cues.
Aschoff & Wever: Ppts in a bunker still had 24–27 hour rhythms without light, supporting internal clocks.
Folkard et al.: Most ppts couldn’t adjust to an externally shortened 22-hour day, suggesting internal clocks are dominant.
Morgan: Transplanted SCNs into hamsters shifted their rhythms—strong evidence of endogenous pacemakers
What are Ultradian Rhythms?
Rhythms occurring more than once in 24 hours. The sleep cycle is a clear example (~90 minutes per cycle). 5 stages identified via EEG:
o Stages 1–2: Light sleep, alpha/theta waves.
o Stages 3–4: Deep sleep (SWS), delta waves.
o Stage 5: REM sleep, brain is active, dreaming occurs, body is paralysed.
* Dement & Kleitman: Found REM linked to dreaming and verified sleep-stage patterns.
What are Endogenous Pacemakers and Exogenous Zeitgebers?
Endogenous Pacemakers
Internal biological structures regulating rhythms. The SCN is the main pacemaker, synchronising rhythms like sleep-wake and body temperature. SCN influences melatonin release from the pineal gland. In absence of light, SCN continues but with slight drift—needs exogenous input to stay accurate.
Exogenous Zeitgebers
External cues resetting the biological clock. Light is the dominant zeitgeber, resetting the SCN via the optic chiasm. Social cues like mealtimes and schedules (e.g., imposed by parents on infants) also entrain rhythms. Research: Adapting to local time zones helps mitigate jet lag. McClintock showed pheromones can influence menstrual rhythms—another form of exogenous control.
