Outline and Evaluate Localisation of Function in the Brain
AO1 Localisation of function describes the theory that specific areas in the
brain are responsible for specific functions, behaviours and activities.
This theory contrasts holism.
The motor area is located in the frontal lobe and responsible for
voluntary movements, damage to this area can lead to an inability to
control voluntary fine movements.
The visual cortex is located in the occipital lobe which processes
visual information from the eyes.
The somatosensory area is located in the parietal lobes and
processes sensory information from the skin. Damage can lead to a
loss of sensitivity in specific areas.
The auditory area is located in the temporal lobe and processes
speech-based information, damage to this area can cause hearing
loss.
Broca’s area is located in the left frontal lobe and responsible for
speech production. Damage to this area can lead to Broca’s Aphasia
which is a difficulty to form complete sentences.
Wernicke’s area is located in the left temporal lobe and responsible
for language comprehension. Damage to this area can lead to
Wernicke’s Aphasia which is a lack of awareness of using incorrect
words.
AO3 1. Research support from Tulving et al who demonstrated using
PET scans that long term memory stores were localised; semantic
memories are recalled from the left pre-frontal cortex and episodic
memories are recalled from the right pre-frontal cortex. Proving
localisation of function theory as different areas have specific
roles.
2. Phineas Gage was injured by a rod that was blasted into the left
side of his brain, through the pre-frontal cortex and caused issues
with decision making, emotion processing and personality
changes. Again, this provides evidence for localisation of function.
3. The limitation of this research is that it is a case study and as
the sample size is only one person, it cannot be generalised to a
population. Furthermore, there is a lack of control over
confounding and extraneous variables, therefore decreasing the
validity of the findings.
4. There is contradictory evidence from Lashley- she removed
the areas of cortex of rats who were learning a maze and found
that the removal has no effect of their progress, suggesting that
for more complex functions, the whole brain is involved. However,
a limitation of this study is that it uses animals meaning there are
issues with ethics and generalisation of the results as human
brains are far more complex than animal brains. This research
would support a more holistic view of brain functioning which
would argue that specific area of the brain cannot be isolated as
they all work together, and isolating areas would be seen as
reductionist.
, Question: Outline and evaluate the effect of endogenous pacemakers and
exogenous zeitgebers on the sleep/ wake cycle.
AO1 Biological rhythms such as the sleep/ wake cycle (circadian rhythm) can be
influenced by endogenous pacemakers (internal body clocks) and exogenous
zeitgebers (external cues in the environment).
Endogenous pacemakers are the internal factors that influence the sleep wake
cycle, such as the superchiasmatic nucleus (SCN) which is a tiny bundle of nerves
located in the hypothalamus. This receives information about light from the optic
nerve, enabling the biological clock to adjust to changing patterns of daylight whilst
we are asleep. It then passes information on day length and light to the pineal gland
which guides the sleep/ wake cycle as it produces melatonin (a chemical that
induces sleep).
Exogenous zeitgebers are external factors that influence the sleep wake cycle for
example, light. It can reset the body’s main endogenous zeitgeber (the SCN) and
thus influences the sleep/ wake cycle due to its control of melatonin production.
Social cues can also be used to control the sleep/wake cycle. This is shown by
babies, who do not have the same sleep/wake cycle as us. Theirs is random. They
are not entrained until they are at least 6 weeks of age, and the bedtimes and
mealtimes, exerted by parents are key Zeitgebers in this process.
AO3 1. Research support from Siffre’s cave study on the influence of endogenous
pacemakers provides evidence that the sleep/wake cycle is controlled by the
SCN. Siffre lived in a cave for 2 months with no natural light and found that his
sleep/ wake cycle maintained a regular cycle of just over 24 hours.
2. This research is limited as he still used artificial light which presented a
confounding variable as the sleep/ wake cycle can be adjusted by the light
meaning the internal validity of this study decreases. Furthermore, this research
is reductionist as it attempts to reduce the sleep wake cycle to biological factors
and ignore environmental ones, reducing the validity. However, it is impossible
to separate endogenous zeitgebers and endogenous pacemakers so their effects
should be seen as combined in a more holistic way. Finally, this research is a
case study on one person and due to the small sample size, the results cannot
be generalised to the population.
3. There is research support for the SCN using animals by DeCoursey et al who
destroyed the SCN connection in the brains of 30 chipmunks who were then
returned to their natural habitat and observed for 80 days. They found that the
sleep/ wake cycle of the chipmunks had disappeared, and a significant
proportion had been killed by predators.
4. This research is also limited as SCN research obscures other body clocks as
many organs have their own body clocks which influence the sleep/wake cycle
so we cannot determine that the effects shown in findings are purely caused by
the SCN.
5. This research is limited as it involves animals, and we know that animal’s
function in a much simpler way than humans meaning the results cannot be
generalised to humans. Furthermore, there are ethical issues associated with
using animals as they cannot provide informed consent and, in this study, some
of the chipmunks were killed. These ethical issues give psychological research a
poor reputation however, we could argue that the benefits of the findings
outweigh the costs (ethical issues considering the animals).
6. Practical application in shift work as research provides an understanding of
the adverse consequences that occur when sleep/ wake cycles are disrupted for
example, shift work is associated with poor health and concentration.
AO1 Localisation of function describes the theory that specific areas in the
brain are responsible for specific functions, behaviours and activities.
This theory contrasts holism.
The motor area is located in the frontal lobe and responsible for
voluntary movements, damage to this area can lead to an inability to
control voluntary fine movements.
The visual cortex is located in the occipital lobe which processes
visual information from the eyes.
The somatosensory area is located in the parietal lobes and
processes sensory information from the skin. Damage can lead to a
loss of sensitivity in specific areas.
The auditory area is located in the temporal lobe and processes
speech-based information, damage to this area can cause hearing
loss.
Broca’s area is located in the left frontal lobe and responsible for
speech production. Damage to this area can lead to Broca’s Aphasia
which is a difficulty to form complete sentences.
Wernicke’s area is located in the left temporal lobe and responsible
for language comprehension. Damage to this area can lead to
Wernicke’s Aphasia which is a lack of awareness of using incorrect
words.
AO3 1. Research support from Tulving et al who demonstrated using
PET scans that long term memory stores were localised; semantic
memories are recalled from the left pre-frontal cortex and episodic
memories are recalled from the right pre-frontal cortex. Proving
localisation of function theory as different areas have specific
roles.
2. Phineas Gage was injured by a rod that was blasted into the left
side of his brain, through the pre-frontal cortex and caused issues
with decision making, emotion processing and personality
changes. Again, this provides evidence for localisation of function.
3. The limitation of this research is that it is a case study and as
the sample size is only one person, it cannot be generalised to a
population. Furthermore, there is a lack of control over
confounding and extraneous variables, therefore decreasing the
validity of the findings.
4. There is contradictory evidence from Lashley- she removed
the areas of cortex of rats who were learning a maze and found
that the removal has no effect of their progress, suggesting that
for more complex functions, the whole brain is involved. However,
a limitation of this study is that it uses animals meaning there are
issues with ethics and generalisation of the results as human
brains are far more complex than animal brains. This research
would support a more holistic view of brain functioning which
would argue that specific area of the brain cannot be isolated as
they all work together, and isolating areas would be seen as
reductionist.
, Question: Outline and evaluate the effect of endogenous pacemakers and
exogenous zeitgebers on the sleep/ wake cycle.
AO1 Biological rhythms such as the sleep/ wake cycle (circadian rhythm) can be
influenced by endogenous pacemakers (internal body clocks) and exogenous
zeitgebers (external cues in the environment).
Endogenous pacemakers are the internal factors that influence the sleep wake
cycle, such as the superchiasmatic nucleus (SCN) which is a tiny bundle of nerves
located in the hypothalamus. This receives information about light from the optic
nerve, enabling the biological clock to adjust to changing patterns of daylight whilst
we are asleep. It then passes information on day length and light to the pineal gland
which guides the sleep/ wake cycle as it produces melatonin (a chemical that
induces sleep).
Exogenous zeitgebers are external factors that influence the sleep wake cycle for
example, light. It can reset the body’s main endogenous zeitgeber (the SCN) and
thus influences the sleep/ wake cycle due to its control of melatonin production.
Social cues can also be used to control the sleep/wake cycle. This is shown by
babies, who do not have the same sleep/wake cycle as us. Theirs is random. They
are not entrained until they are at least 6 weeks of age, and the bedtimes and
mealtimes, exerted by parents are key Zeitgebers in this process.
AO3 1. Research support from Siffre’s cave study on the influence of endogenous
pacemakers provides evidence that the sleep/wake cycle is controlled by the
SCN. Siffre lived in a cave for 2 months with no natural light and found that his
sleep/ wake cycle maintained a regular cycle of just over 24 hours.
2. This research is limited as he still used artificial light which presented a
confounding variable as the sleep/ wake cycle can be adjusted by the light
meaning the internal validity of this study decreases. Furthermore, this research
is reductionist as it attempts to reduce the sleep wake cycle to biological factors
and ignore environmental ones, reducing the validity. However, it is impossible
to separate endogenous zeitgebers and endogenous pacemakers so their effects
should be seen as combined in a more holistic way. Finally, this research is a
case study on one person and due to the small sample size, the results cannot
be generalised to the population.
3. There is research support for the SCN using animals by DeCoursey et al who
destroyed the SCN connection in the brains of 30 chipmunks who were then
returned to their natural habitat and observed for 80 days. They found that the
sleep/ wake cycle of the chipmunks had disappeared, and a significant
proportion had been killed by predators.
4. This research is also limited as SCN research obscures other body clocks as
many organs have their own body clocks which influence the sleep/wake cycle
so we cannot determine that the effects shown in findings are purely caused by
the SCN.
5. This research is limited as it involves animals, and we know that animal’s
function in a much simpler way than humans meaning the results cannot be
generalised to humans. Furthermore, there are ethical issues associated with
using animals as they cannot provide informed consent and, in this study, some
of the chipmunks were killed. These ethical issues give psychological research a
poor reputation however, we could argue that the benefits of the findings
outweigh the costs (ethical issues considering the animals).
6. Practical application in shift work as research provides an understanding of
the adverse consequences that occur when sleep/ wake cycles are disrupted for
example, shift work is associated with poor health and concentration.
