biopsychology 2

what and where are the lobes is the cerebrum

What is the main function of the frontal lobe

Responsible for

• decision making

• personality

• planning

• voluntary movement.

It also contains the motor cortex and Broca’s area

What is the main function of the temporal lobe?

Responsible for

• hearing

• memory

• language comprehension

Contains the auditory cortex and Wernicke’s area.

What is the main function of the parietal lobe?

Processes sensory information such as

• touch

• pressure

• pain

• temperature

It contains the somatosensory cortex.

What is the main function of the occipital lobe?

Responsible for processing

• visual information.

Contains the visual cortex

How is the cerebrum divided, and how do the halves communicate?

left and right hemispheres

connected by/ communicate through a thick band of nerve fibers - corpus callosum

What is hemisphere lateralization?

The idea that each hemisphere specializes in different tasks:

Left Hemisphere - Language/speech and logic/analysis.

Right Hemisphere - Spatial awareness and creativity

what does the cerebellum do

controls motor skills and balance (contains grey matter/ cortex)

What two main structures compose the diencephalon?

The thalamus and the hypothalamus

what is the function of the thalamus

receives impulses from the senses and sends them to the appropriate areas of the brain

what is the function of the hypothalamus

links the endocrine system and the nervous system

brainstem functions

carries out vital functions; breathings, swallowing

what is cortex/ grey matter

a mass of cell bodies of neurons

What does white matter in the brain contain

Myelinated axons of neurons

What is the function of the motor cortex

generates voluntary motor movements

found in the precentral gyrus

regions organised logically

What are the two main layers of the cerebrum

• Cerebral Cortex- The outer layer responsible for conscious thought

• White Matter- The inner layer that transmits nerve signals throughout the brain

function of the somatosensory cortex

detects sensory events (such as touch, pressure, and pain)

found in the postcentral gyrus

function of the auditory cortex

processes sounds (verbal/auditory)

ear→brainstem→thalamus→auditory cortex

function of the visual cortex

processes visual information

retina→thalamus→visual cortex

Define the theory of "Localisation of Brain Function."

different, specific areas of the brain control distinct functions

Define the "Holistic Functioning" theory of the brain

functions cannot be assigned to specific areas because they require multiple parts of the brain working together

evidence for brain localisation

CASE STUDY: PHINEAS GAGE

• Railway worker in accident in which rod was blasted through chin and out of forehead

• Recovered well but personality changed (became rude and used vulgar language)

• Damage specifically to his left frontal lobe completely altered his personality, linking that area to personality control.

CASE STUDY: PATIENT TAN

• Could only say "tan"; otherwise understood language perfectly

• Autopsy showed a lesion in the left inferior frontal gyrus

• Established Broca's area as the centre for speech production

contralateral brain functions meaning

The right side of the brain controls and perceives the left side of the body, and vice versa.

what is bronca’s area

a region in the posterior portion of the left frontal hemisphere responsible for speech production and ensuring speech is fluent.

what is wernicke’s area

a region located in the posterior portion of the left temporal lobe responsible for language processing and understanding the meaning of words

What is Expressive (Broca’s) Aphasia

An impaired ability to produce fluent speech, usually caused by damage to Broca’s area.

What is Receptive (Wernicke’s) Aphasia

An impaired ability to understand language or extract meaning from words, usually caused by damage to Wernicke's area

evaluate case studies of aphasia patients

• Patients are only studied after brain injury, so researchers cannot be certain if the language defects were present originally (low internal validity)

• Individuals with brain damage do not accurately represent the wider, healthy public population

Define Lashley's "Equipotentiality Theory."

basic sensory and motor skills are localised, higher mental functions are not

allowing intact cortex areas to take over responsibilities after an injury.

According to the equipotentiality theory, what determines the severity of brain damage?

The extent (amount) of brain damage rather than its specific location.

evaluate localisation of brain functions

ignores individual differences - bavelier and harasty

communication is more important than localisation - wernicke and Joseph Dejerine

evidence wernicke’s area playing a factor in language comprehension

DEJERINE

• Damaging the connection between the visual cortex and Wernicke’s area caused a total loss of reading ability.

What did Wernicke mean when he claimed brain regions are "interdependent"?

Although specific regions have specialist functions, they must interact with each other in order to work.

evidence for equipotentiality theory

LASHLEY

• 50 rats ran a maze before and after areas of their brain cortex were destroyed. 

• Lashley found that the ability to rerun maze was affected by how much brain cortex was destroyed rather than which area was destroyed.

• Supports equipotent theory and discredicts localisation of brain function theory.

explain individual differences as an argument against localisation

BAVELIER ET AL

• observed activity in the right and left temporal lobes, the left frontal lobe and left occipital lobe.

• found considerable variability in patterns of activation across different individuals when reading.

HARASTY ET AL

• found women have proportionately larger Broca’s and Wernicke’s areas than men

What is split-brain patient?

a patient whos nerve fibres that form the corpus callosum have been severed; the aim is to prevent the violent electrical activity of epileptic seizures from crossing between hemispheres

if a split-brain patient sees an image in their Right Visual Field (RVF), can they say what it is?

yes, because the image goes to the left hemisphere, which contains the language centres.

if a split-brain patient sees an image in their Left Visual Field (LVF), can they say what it is?

no, because the image goes to the right hemisphere, which cannot communicate with the language centres in the left hemisphere.

evidence for evolutionary advantages of brain lateralisation?

ROGERS ET AL

• found that in the domestic chicken, brain lateralisation increases neural processing capacity

• allowing an organism to perform two different tasks simultaneously

What health disadvantage is associated with a highly dominant right hemisphere?

• increased likelihood of being left-handed

• higher rates of allergies

• immune system disorders

evidence challenging early split-brain findings

CASE STUDY: J.W.

• J.W. developed the ability to speak out of his right hemisphere

• allowing him to talk about information presented to either visual field.

What is a major sample size limitation in split-brain research according to Andrewes (2001)?

The procedure is very rare, meaning many studies draw conclusions based on just a single participant (N=1).

what is the method for split brain research

• researcher cuts the patients corpus callosum and presents stimuli to either the left or right hemisphere

• patient then must point with their hand to the stimulus just shown

• if a function isn’t hemispherically lateralized the patient should point as normal. if it is, the patient will be unable

evidence for split brain research

SPERRY

• presented images to either a patients left or right hemisphere

• patients could point to 1 of 4 images that matched the image, regardless of hem

• but he found participants could not verbally describe the image, if presented to the left hem

• concluded language is hem lateralized to the left

evaluate split brain research

• samples include small group of people with brain abnormalities (extraneous variable)- cant generalise

• not all findings have been replicated - recent studies show not all aspects of language are controlled by the left

• case studies that are exceptions - patient EB had his left hem removed when 2yo, gained language skills back after rehabilitation (can be taken over by right)