Localisation of Function in the Brain Flashcards
What did Wernicke and Broca discover
specific areas of the brain correlated to certain psychological and physical functions - contrasts with theory of brain being holistic
What is localisation of function
supported by Wernicke and Broca, idea that brain will undertake different tasks and link to certain body parts
What if area of brain is damaged
function of body part associated with it will also be damaged
What is the idea of lateralisation
brain - divided into two hemispheres - lateralisation is when a certain function is controlled or dominated by one hemisphere
What does the left hemisphere control
the right hand side of the body
What does the right hemisphere control
the left hand side of the body
What are the concentric layers of the brain
Central core, limbic system and cerebral cortex
What is the central core
Regulates breathing, sleeping, temperature
Includes hypothalamus in mid-brain
Helps endocrine system regulate homeostasis
What is homeostasis
Process by which body controls physiological state
What is the the limbic system
Controls emotions
Includes hippocampus
Found around central core, connected with hypothalamus
What is the cerebral cortex
Outer layer of brain - 3mm thick, grey, more developed in humans than in any other animal
What is the corpus callous
a nerve bundle which enables messages to be sent from one hemisphere to another
What are the 4 parts of the hemispheres
Frontal lobe, parietal lobe, temporal lobe, occipital lobe
What is the motor area
found in frontal lobe
controls voluntary movement in opposite side of body
damage to motor area causes loss of fine motor skills
What is the somatosensory area
found in parietal love
separated from motor area by central sulcus - valley
holds sensory info from skin
What is the visual area
found in occipital lobe
eyes send info from right visual field to left visual area and vice versa
damage to area - blindness or loss of visual field
What is the auditory area
found in temporal lobe
analyses speech-based info
damage to area - hearing loss
Where is language confined
the left side of the brain, unlike other areas which control movement and sight found in both hemispheres
What did Paul Broca discover
an area with frontal lobe responsible for speech production - Broca’s area
Broca - surgeon in 1880s
Damage to Broca’s area
leads to Broca’s aphasia - causes slow, laborious and fluency-lacking speech
What was Karl Wernicke studying
patients who had no problem producing speech, they just couldn’t understand it - speech was fluent but meaningless
What did Wernicke discover
Wernicke’s area - found in left temporal love - responsible for language comprehension
Damage to area - Wernicke’s aphasia - neologisms or non-sensical words
Brain scan evidence for localisation
much evidence supporting localisation of functions as opposed to them being holism
Petersen et al. (1988) - used brain scans to link different areas to different functions, Broca’s area was active during reading task and Wernicke’s area was active during listening task
Tulving et al. (1994) - discovered that episodic and semantic memories are found in different parts ion prefrontal cortex
Neurosurgical evidence
Surgically removing or destroying areas of brain in an attempt to control behaviour became a practice in the 1950s
Lobotomies would take place, cutting connections in frontal lobe to control aggression
Neurosurgery is still used today but very rarely
Dougherty et al. (2002) - examined 44 OCD patients who underwent cingulotomy
1/3 of these patient responded successfully to the surgery after 32 weeks
strong suggestion that symptoms and behaviour of serious mental disorders are localised
Case study evidence
Phineas Gage - 1848
a metre-long pole was propelled through Gage’s head, taking most of the left frontal lobe with it - he survived but his personality changed from being calmed and reserved to rude and quick-tempered
Suggests that frontal lobe could be responsible for regulating mood
Lashley’s research
Lashley (1950) - processes involving learning and other higher functions aren’t localised
argued that they are distributed holistically
lashley removed between 10 and 50% of the cortex in rats trying to learn a maze - no area proved to be more important or damaging to their ability to learn than any other
Learning requires all parts of cortex rather than certain area - learning too complex
Plasticity
cortical remapping - if brain is damaged ins one way and a particular function is weakened or lost, the brain may be able to reorganise and recover lost function - Law of Equipotentiality - suggests that rest of brain lend hand - lost action can be achieved again
Number of stroke victim cases where they have been able to recover seemingly lost abilities
