T H E S T U D Y O F W H A T S T R U C T U R E S H A V E
W H A T F U N C T I O N S
I B L E A R N I N G O U T C O M E :
E X P L A I N O N E S T U D Y R E L AT E D TO
L O C A L I Z AT I O N O F F U N C T I O N O F T H E B R A I N
I N I B - S P E A K T H I S M E A N S “ G I V E A D E TA I L E D
A C C O U N T I N C L U D I N G R E A S O N S A N D C A U S E S ”
Localization of Function
Why is brain function special?
The human brain is capable of carrying out different
functions such as vision movement, comprehension,
speech, hearing and overall body control.
Unlike other organs such as lungs or kidneys that
perform the same function, different parts of the
brain execute different functions.
Therefore, localization of function is relevant in the
But how do we find out? Methods involving
Accidental damage – Phineas Gage (frontal cortex)
Deliberate damage/lesion (ablation)
Stimulation of the brain – electrodes inside the brain
Jill Bolte Taylor, the doctor who had a stroke in her left
„Tan‟ – Broca‟s patient who could only say „tan‟ because of
brain damage. Broca‟s area was revealed in (postmortem)
Phineas Gage – had a rod go through his frontal cortex
Clive Wearing – „flu‟ on his temporal lobe and hippocampus
causing anterograde amnesia
Accidental damage – and cases we know of
lesions on the hypothalamus of rats disturbed eating behavior.
removing the amygdala in animals reduces aggression.
case of HM who had his hippocampus removed.
Sperry cut Corpus Callosum in epileptic patient, who then
experienced „split brain‟
mental inmates were given lobotomy to control their behavior.
I knew you would ask about split brain!
Sperry cut the patient‟s corpus callosum to alleviate
their epilepsy symptoms. This structure enables the
two hemispheres to communicate.
Split brain – right and left are „divorced‟
The patients hemispheres were disconnected, and
they experiences „split brain‟
A patient with a split brain, when shown an image in
his or her left visual field, will be unable to vocally
name what he or she has seen.
This is because the speech-control center is in the
left side, and the image from the left visual field is
sent only to the right side of the.
Key+Study - watch this clip
Delgado stimulated areas of the limbic system to inhibit
aggression in a charging bull with a remote control - while
standing right in front of it!
Penfield stimulated areas of the cortex in patient during
surgery to locate areas controlling movement, hearing, sense
Evaluation – can you evaluate the methods?
Lack of precision – we cannot control the damage
Hard to compare before and after damage (no concrete records
Confounding variables – could Gage‟s behavior be caused by
Ethically good, as the damage occurs naturally in these natural
Ethical problems – not just in humans!
Animal studies – we cannot necessarily generalize
Neuroplasticity – the brain can compensate, so the missing
part may not be showing
Good because there is greater control – precision of damage
and therefore easier to compare
Less harmful than ablation
More valid – a better way of investigation „living‟ function of
However, it is invasive – surgery is risky
The brain‟s interconnectedness makes it hard to know if the
stimulated areas affect other areas.
Discussion – can we localize function?
”The brain is a highly complex, heavily
interconnected system that displays non-linear
properties and this is clearly a short fall of localization
(This means that we can argue that is is hard to
localize a function to a specific structure of the brain,
since the structures are interconnected)
Methods of localization that do not involve
Direct reading of neuron activity
Very precise, but too focused. Is furthermore invasive and
External recording (EEG)
Non-invasive, and helpful in studying sleep, epilepsy etc.
Crude and imprecise
Scanning techniques (Still pictures – CAT, Dynamic
pictures – fMRI, PET)
Detailed knowledge of structure and function in conscious
patients – even while they are performing tasks
Expensive, hard to interpret, sensitive to disruption (e.g.
movement), uncomfortable for patients
Structures and their function
We know of
Broca‟s area (language production, pt. Tan)
Wernicke‟s area (language understanding)
Frontal lobes (judgment, inhibition, pt. Phineas Gage)
Here is a more detailed description
Cerebral Cortex is asymmetrical
Controls right side of the
Controls left side of the
We will focus on the limbic system – specifically
WE WILL USE
THE CASE OF
Born in Connecticut in
Suffered from severe
Had neurosurgery in
Doctors removed parts
of his temporal lobe to
alleviate his symptoms
Bilateral Medial Temporal Lobe resection
Doctor‟s removed large portions of the temporal lobe
from both hemispheres of the brain.
H. M.‟s condition justified drastic measures, and the
surgery he underwent was extensive and radical.
Tissue was removed from the anterior (front) tips of
the temporal lobes on the medial (inner) surface of
the brain, extending 8cm backwards.
The resection therefore completely removed the
amygdala, the entorhinal and perirhinal cortices, and
about two-thirds of the hippocampus
The surgery was a success!
It reduced his seizures to two a year!
BUT: HM was left with profound anterograde amnesia
and partial retrograde amnesia.
To this day, he has no memory of anything that has
happened since he underwent surgery, and cannot
acquire new factual knowledge about the world around
He is unable to retain any kind of new information for
more than several minutes.
And he cannot remember much of what happened in the
decade prior to his surgery.
HM upon losing his hippocampi
"Right now, I'm wondering, have I done or said
anything amiss? You see, at this moment everything
looks clear to me, but what happened just before?
That's what worries me. It's like waking from a
dream. I just don't remember."
What Henry can and can‟t remember
Read the document, and answer these questions
What does HM‟s case teach us about the role of the
Which type of memory was damaged?
Which part remained intact?
What can we conclude from this natural experiment
in terms of localization of function?
Implications/Conclusions – see point 2.4
The hippocampus is important in memory
processing and particularly in the storage of new
H.M. could learn a few new procedural memories so
this indicates that such memories are not stored via
The fact that H.M. had deficits in one part of the
memory system but not in others is evidence that the
brain has several memory systems and that these are
supported by distinct brain regions.
Memory processes are much more complex – the hippocampus is
very important in the storage of new memories it is not the only
structure involved in the process.
Cortical areas are important for long-term memory, for facts and
events (semantic and episodic memories), and the use of that
information in daily life.
Ethical considerations in this case study. Lack of consent due to
memory loss. However, the findings of the study are very important
and this justifies it.
It is not usually possible to use the findings from a single case study
to generalize about a larger population, but since the findings from
other case studies of people with brain damage like H.M. tend to
support those from this case study, it may be possible to generalize
to some extent.
References to studies
Brenda Milner (1957) was the first to report the case of
H.M. and the profound effects on memory functioning,
following an operation which removed the hippocampus
and adjacent areas in H.M.‟s brain.
Corkin et al. (1997) did a MRI scan of H.M‟s brain. Brain
imaging was used because it allowed the researchers to
get a precise picture of the brain damage. They
discovered that parts of the temporal lobe, including the
hippocampus and the amygdala, were missing, but also
that the damage was not as extensive as previously
8 Tips for writing a good SAQ
Make sure you understand the command term and
know the difference between explain or discuss or
whatever you might be asked to demonstrate your
understanding of the Learning Outcome
Define the key words in the SAQ and integrate the
definitions into a “In other words…” sentence.
Make sure you use the words from the question in
your answer at least two or three times. If the SAQ is
about physiology use this word rather than brain or
8 Tips for writing a good SAQ
Use studies to support your explanations. Give a
brief summary of the study and then explain why this
Take every opportunity to evaluate the study but do
not just outline every strength and limitation, only
the relevant ones.
For example there is no need to discuss ethical
considerations with the Davidson meditation study
from the BLOA, but the small sample size is relevant
as it makes generalizing his finding that cognition
can change brain physiology more limited.
8 Tips for writing a good SAQ
Aim for a short introduction and conclusion. These
can be just one sentence in length.
If you are asked about two hormones or two studies
or two neurotransmitters make sure you have two
Example of an SAQ localization of function
Explain One Study Related to Localization of Function of the Brain
One study which focused on localization of function in the brain was conducted by French
physician Paul Broca in the 19th Century. Broca set out to test his theory that damage to a
specific part of the brain (the frontal lobe) was responsible for problems with speech.
Initially, Broca tested his theory through the use of case studies, one of which was on a patient
named „Tan‟ (the only word Tan was able to say). During these case studies, Broca gathered a
substantial amount of evidence including the problems each individual faced and details of any
medical issues. Broca found that his patients all had two main factors in common – they
understood language but had distinct problems with speech, and each patient had suffered
some element of damage to the left side of their brains in earlier life. This led Broca to
hypothesize that there must be a link between specific head trauma and the development of
After Tan‟s death, Broca carried out a postmortem study, and found that Tan had lesions on the
frontal lobe of his left hemisphere where damage had occurred earlier on in his life. Subsequent
post-mortem research of several of his other patients identified that they too had specific
damage to the left frontal lobe – an area now known as Broca‟s area. The research that Broca
carried out during his lifetime led him to the conclusion that different parts of the brain must be
responsible for specific functions. In this case, speech can be said to be localized to the frontal
cortex of the left hemisphere, a finding which has been supported by recent empirical research.
Mark Band/Level descriptor
Zero: The answer does not reach a standard described by the descriptors
Low (1-3): There is an attempt to answer the question, but knowledge and
understanding is limited, often inaccurate, or of marginal relevance to the
Mid (4-6): The question is partially answered. Knowledge and
understanding is accurate but limited. Either the command term is not
effectively addressed or the response is not sufficiently explicit in
answering the question.
High (7-8 ): The question is answered in a focused and effective manner
and meets the demands of the command term. The response is supported
by appropriate and accurate knowledge and understanding of research.
Where would you rate this SAQ and why? Remember the answer
must observe the command term!