discuss localisation of function in the brain
paragraph one:
-Localisation of function is the idea that certain functions (e.g. language, memory, etc.)
have certain locations or areas within the brain.
-This idea has been supported by recent neuroimaging studies, but was also
examined much earlier, typically using case studies.
-At the back of the brain, in the occipital lobe is the visual area, which receives and
processes visual information.
-Information from the right-hand side visual field is processed in the left hemisphere,
and information from the left-hand side visual field is processed in the right
hemisphere.
-The visual area contains different parts that process different types of information
including colour, shape or movement.
-Damage: leads to partial or complete loss of vision called cortical blindness.
Damage to one cortex can lead to loss of vision in the opposite visual field
-The human brain has two primary auditory cortices, one in each hemisphere.
-The primary auditory cortex in both hemispheres receives information in both ears
via two pathways that transmit information about what the sound is and its location
(in a similar way to how the visual information gets passed to the visual cortex).
-The information from the right ear goes primarily to the left hemisphere but some is
transmitted to the left primary auditory cortex too. This happens in the same way with
information from the left ear.
Damage: Trauma to the auditory cortex can lead to cortical deafness. Patient is
unable to hear, but no damage to the structure of the ear.
-Movement is centred on the primary motor cortex of the brain which sends
messages to the muscles via the brain stem and spinal cord.
-The motor cortex is particularly important for complex movement and not basic
actions such as coughing, crying or gagging.
-Damage: Injuring the motor cortex results in the loss of muscle function or after
severe trauma, paralysis. This occurs on the opposite side of the body to the
damage due to contralaterality.
-Somatosensory refers to the sensation of the body.
-The somatosensory cortex lies next to the motor cortex in the brain. It perceives
touch, so the amount of neuronal connections needed dictates the amount of
somatosensory cortex needed for that area of the body.
-Damage: Loss of sensation, ignoring areas of the body (neglect syndrome), loss of
ability in recognising objects by their feel (agnosia). Effects are in opposite side to
damage (contralateral)
, paragraph two: (supporting)
-One such case study is that of Phineas Gage, who in 1848 while working on a rail
line, experienced a drastic accident in which a piece of iron went through his skull.
-Although Gage survived this ordeal, he did experience a change in personality, such
as loss of inhibition and anger. This change provided evidence to support the theory
of localisation of brain function, as it was believed that the area the iron stake
damaged was responsible for personality.
paragraph three: (criticism)
-The primary limitation of the Phineas Gage case is its small sample size, as it is a
single case study. Small samples can be less representative of the general
population, making it challenging to draw broad conclusions or generalize the
findings.
-however, a number of objective studies also demonstrate localisation of function
-eg. Tulving demonstrated episodic and semantic memories reside in different areas
of the prefrontal cortex
paragraph four: (against)
-Lashley found that when the brain area becomes damaged through accident or
illness and a particular function has been compromised or lost, the rest of the brain is
able to reorganise itself in an attempt to recover the lost function.
-for example there are cases of several stroke victims being able to recover abilities
that were seemingly lost as a result of their illness
-suggests the localisation theory may be too simplistic and the brain is able to be
more adaptive and operate in a holistic way
paragraph five:
-Located in the top temporal lobe, Wernicke's area is responsible for speech
comprehension. Discovered after case studies of individuals who could produce
fluent sounding speech that made little sense.
-Damage: Wernicke's aphasia (Also known as receptive/sensory aphasia). Difficulty
understanding speech or written language, speech sounds fluent but lacks meaning/
nonsense words.
-Located in the left frontal lobe, Broca's area is responsible for speech production.
Discovered after case study and post mortem of Tan whon
-Damage: Broca's aphasia (Also known as expressive/motor aphasia). Difficulty
producing fluent speech, speech is slow and effortful. Speech has missing words
leading to poor grammar.
paragraph six: (criticism)
more important to investigate how the brain areas communicate with each other,
rather than focusing on specific brain regions
paragraph one:
-Localisation of function is the idea that certain functions (e.g. language, memory, etc.)
have certain locations or areas within the brain.
-This idea has been supported by recent neuroimaging studies, but was also
examined much earlier, typically using case studies.
-At the back of the brain, in the occipital lobe is the visual area, which receives and
processes visual information.
-Information from the right-hand side visual field is processed in the left hemisphere,
and information from the left-hand side visual field is processed in the right
hemisphere.
-The visual area contains different parts that process different types of information
including colour, shape or movement.
-Damage: leads to partial or complete loss of vision called cortical blindness.
Damage to one cortex can lead to loss of vision in the opposite visual field
-The human brain has two primary auditory cortices, one in each hemisphere.
-The primary auditory cortex in both hemispheres receives information in both ears
via two pathways that transmit information about what the sound is and its location
(in a similar way to how the visual information gets passed to the visual cortex).
-The information from the right ear goes primarily to the left hemisphere but some is
transmitted to the left primary auditory cortex too. This happens in the same way with
information from the left ear.
Damage: Trauma to the auditory cortex can lead to cortical deafness. Patient is
unable to hear, but no damage to the structure of the ear.
-Movement is centred on the primary motor cortex of the brain which sends
messages to the muscles via the brain stem and spinal cord.
-The motor cortex is particularly important for complex movement and not basic
actions such as coughing, crying or gagging.
-Damage: Injuring the motor cortex results in the loss of muscle function or after
severe trauma, paralysis. This occurs on the opposite side of the body to the
damage due to contralaterality.
-Somatosensory refers to the sensation of the body.
-The somatosensory cortex lies next to the motor cortex in the brain. It perceives
touch, so the amount of neuronal connections needed dictates the amount of
somatosensory cortex needed for that area of the body.
-Damage: Loss of sensation, ignoring areas of the body (neglect syndrome), loss of
ability in recognising objects by their feel (agnosia). Effects are in opposite side to
damage (contralateral)
, paragraph two: (supporting)
-One such case study is that of Phineas Gage, who in 1848 while working on a rail
line, experienced a drastic accident in which a piece of iron went through his skull.
-Although Gage survived this ordeal, he did experience a change in personality, such
as loss of inhibition and anger. This change provided evidence to support the theory
of localisation of brain function, as it was believed that the area the iron stake
damaged was responsible for personality.
paragraph three: (criticism)
-The primary limitation of the Phineas Gage case is its small sample size, as it is a
single case study. Small samples can be less representative of the general
population, making it challenging to draw broad conclusions or generalize the
findings.
-however, a number of objective studies also demonstrate localisation of function
-eg. Tulving demonstrated episodic and semantic memories reside in different areas
of the prefrontal cortex
paragraph four: (against)
-Lashley found that when the brain area becomes damaged through accident or
illness and a particular function has been compromised or lost, the rest of the brain is
able to reorganise itself in an attempt to recover the lost function.
-for example there are cases of several stroke victims being able to recover abilities
that were seemingly lost as a result of their illness
-suggests the localisation theory may be too simplistic and the brain is able to be
more adaptive and operate in a holistic way
paragraph five:
-Located in the top temporal lobe, Wernicke's area is responsible for speech
comprehension. Discovered after case studies of individuals who could produce
fluent sounding speech that made little sense.
-Damage: Wernicke's aphasia (Also known as receptive/sensory aphasia). Difficulty
understanding speech or written language, speech sounds fluent but lacks meaning/
nonsense words.
-Located in the left frontal lobe, Broca's area is responsible for speech production.
Discovered after case study and post mortem of Tan whon
-Damage: Broca's aphasia (Also known as expressive/motor aphasia). Difficulty
producing fluent speech, speech is slow and effortful. Speech has missing words
leading to poor grammar.
paragraph six: (criticism)
more important to investigate how the brain areas communicate with each other,
rather than focusing on specific brain regions
