THE NEURAL BASIS FOR COGNITION
In this chapter, we will study the brain functioning that makes COGNITION possible. We will
also be learning about the methods used in learning about the brain (neuroimaging).
What is COGNITION?
Very important: Each part of the brain has its own SPECIALIZED function, and or behaviour,
thoughts and feelings almost always depend on many brain regions working together. (Even for
what you consider the most simplest of actions!)
A Preview of the Upcoming Chapter: We will gain an overview of how the brain is built, and
how it works, emphasizing the FUNCTION of each region. (Be prepared for a lot of parts!!!!!!)
-these functions are identified through neuroimaging data, which can assess
the activity level in different areas of the brain…
We will be examining the visual system in depth. Why the visual system? Because the visual
system is what lets us see and understand the visual system around us, it is a gateway of vast
information. The visual system is an example of what we can learn by deeply studying the brain.
What is the Key point in Studying the Visual System?
Visual system shows that analysis of visual input occurs as soon as visual information enters
the nervous system. This analysis depends on many highly specialized regions of the brain
working in parallel with each other.
Brain damage is deeply unfortunate. It is through brain damage, that we have gained our deepest
insights about the brain. –One example in particular:
CAPGRAS SYNDROME- What does Capgras Syndrome teach us?
Damage anywhere in the brain can produce SPECIFIC, and in this case very disruptive
How do people get Capgras syndrome?
i)In elderly, it may accompany Alzheimer’s disease.
ii) Through various injuries to the brain.
What is the “HALLMARK” of Capgras syndrome?
People afflicted with Capgras syndrome are able to intellectually recognize
the people in their world (their spouse, friend, mom etc.), but instead of feeling familiarity and
responding with warmth, they believe that their ―close one is actually an imposter, doing an
amazing job at impersonating the REAL person. The Capgras patient notes that she sounds
just like her and that she looks just like her. However, he believes that there are slight differences between the imposter and the person whom he is impersonating. The real person, is believed to
have been kidnapped and replaced (patient offers a bizarre explanation). These belief prompts
feeling of suspicion and frustration in the Capgras patient (“Why is nobody else realizing this as
well, that my wife has obviously been kidnapped?”) -------You can see how this can lead to
violence, by the person with Capgras syndrome, towards the imposter, who is the actual loved
________How do researchers explain this? What’s their THEORY?
Researchers propose that facial recognition involves TWO SEPARATE systems.
What are these two separate systems?
1) INTELLECTUAL recognition, which leads to COGNITIVE APPRAISAL. A judgement is
made: (“I know what my dad looks like and I perceive that you closely look like him.”)
2) EMOTIONAL, GLOBAL APPRAISAL-(“You look familiar, and also generate a warm
response in me.”) …
(1.) + (2) = Concordance of both appraisals lead to certainty of recognition (“You ARE my
In Capgras syndrome, emotional processing is disrupted, leading to (1) intellectual recognition
WITHOUT familiarity and warmth. It stops at: (“Hey, you look like my dad, but don’t trigger
any sense of familiarity, so you must be someone else.”….Later on…”What did you do with
__________Is the above hypothesis SUPPORTED by evidence?
We have 2 types of evidence.
2) Psychology Laboratory Findings (starts on page 7)
1) We can determine if we are thinking about Capgras syndrome in the right way, by
looking at NEUROIMAGING.
Neuroimaging: non-intrusive, high quality, 3D images of living brain.
Neuroimaging can tell us what is where, the shape of parts and the connection b/w parts, it
can show tumors and missing structures.
Neuroimaging tells us, that in Capgras syndrome, there are abnormalities in several brain
areas (2 are talked about in the text.): i. In the circuits involving the AMYGDALA (located
in right temporal lobe)--CHECK
ii. FRONTAL LOBE (particularly prefrontal cortex
Brain Abnormality: What do we already What does other What links can
know about that biological evidence make between that
brain region? say about this brain region, and
region? the role it plays in
1) Circuits involving -Amygdala is the 1) Amygdala helps -is important for
Amygdala ―emotional people remember supporting feelings of
(temporal lobe, evaluator‖, which emotional events of familiarity. With
right side of brain) detects + and – their lives. damaged amygdala,
stimuli (+: associated 2) Amygdala plays a person WON’T
with safety, rewards) experience warm
role in decision- sense of feeling good
(- associated with making, esp. where
threat or danger.) you rely on emotional or secure, when
looking @ close
evaluation of your one’s familiar face.
Therefore, face won’t
seem familiar to
2) Frontal Lobe fMRI shows that the i)absence of planning Damage to this area
(specifically) in the prefrontal cortex is and analysis in dream can be attributed to
right particularly active, in state, explains why fact that Capgras
PREFRONTAL tasks needing careful dreams don’t make patients cannot
CORTEX. planning and sense a lot discern real from
analysis. unreal, judge the
ii) role of frontal lobesensibility of beliefs,
is diminished during
hallucinations in thus being inclined to
Schizophrenia bizarre hypotheses to
explain things. (“My
them unable to wife was abducted,
separate thoughts and a robot is
from outside voices,
and imagined events
from real. Temporal lobe: the lobe of the cortex lying inward and down from the temples. The temporal
lobe in each cerebral hemisphere involves the primary auditory projection area, Wernicke’s area,
and subcortically, the amygdala and hippocampus.
When something is subcortical, it means that something is beneath the surface. (i.e., it is beneath
Cortex: the outermost surface of an organ in the body
Amygdala and hippocampus, are subcortical structures, meaning they exist beneath the cortex.
While trying to comprehend the above chart, your eyes must have stumbled upon
―fMRI‖…What is that?
What is an fMRI? (A neuroimaging technique)
fMRI technique can tell us the moment-by-moment activity level in different sites in a living
brain (kind of like giving us sports commentary, I feel)
Can show which part of brain is active when partaking in particular tasks (like: reading
these notes, watching TV, listening to music)..from this we can discern what that brain
area’s function is, what it does.
WILL BE DISCUSSED LATER.
Psychology Laboratory Findings (thanks to: Ellis, lewis, Ramachandran and Blakeslee)
Recognition of ALL stimuli involve two separate mechanisms:
One mechanism is rooted in FACTUAL knowledge.
The other mechanism is more emotional, related to warmth and
BOTH, cognitive neuroscience (see first column specifically) and cognitive psychology (the
psychology laboratory findings, above) confirm the initial hypothesis, researchers used to
explain Capgras syndrome. But, by studying Capgras syndrome we also learned a lot about
We learnt that:
-amygdala responsible for feelings of familiarity and security
-CAPGRAS syndrome has taught us that the emotional evaluator
works SEPARATELY from the factual information evaluator, explaining why the head and heart might want different things (in everyday words). (Someone’s evaluation of facts
leads to one conclusion, while the emotional evaluation leads to another conclusion.)
-simplest of achievements require the integration, cohesiveness and coordination of many
If you want to recognize your dad, steps taken are:
1) Factual memory stores what your dad looks like
2) You analyze the visual input received when looking at the face, you are presented
3) You compare 1) and 2). Is there a match? Do (1) and (2) look alike?
Also, an emotional evaluation of the input occurs (as we learnt from Capgras
syndrome), in a different site (the amygdala0.
Yet, again, another different site synthesizes all the data obtained in steps (1) to (4)
to reach a sensible conclusion. If it is deemed that he IS your dad, a warm response
is evoked. However, if it is your dad, but looks he different from what you
remember him as, a plausible explanation is produced (“Oh, he got a haircut.”)
Technical Foundations of Brain:
Brain’s weight is 3-4lbs (size of small melon)
Extraordinary: Brain contains both nerve cells and glial cells.
Contains 1 trillion nerve cells, each of which is connected to 10,000
others, for roughly 10 million billion connections
Contains appx 10 trillion glial cells (outnumber nerve cells by 10:1
Brain is densely packed organ.
Symptoms produced by brain damage depend upon LOCATION of damage.
1. Phineas Garg: damage in frontmost part of brainsymptom: severe
personality and emotional problems
2. Paul Broca discovered damage on left side of brainsymptom: disruption in
3. Edouard Claperede discovered that profound memory loss occurs, when
other parts of the brain are damaged.
Cherish your brain.
SO: Location! Location! Location is everything, like real-estate in the brain!
Now, we will look at the particular where’s of the brain: Human brain is divided into 3 main structures: hindbrain, midbrain and
forebrain. Start referring to figure 2.2, from now on.
Part of Brain HINDBRAIN MIDBRAIN FOREBRAIN
region. Focus is
LOCATION -sits on top of -completely -covered by
-WHERE IS IT? spinal chord hidden by CORTEX, so the
-mostly hidden forebrain. cortex of
from view by forebrain is what
forebrain we can we see,
when we look @
diagrams of brain.
WHAT ARE -includes -coordinate -most important
FUNCTIONS structures for movements, esp. in supporting
ASSOCIATED controlling crucial precise, eye intellectual
WITH IT? life functions movements. functioning.
-heartbeat and -has circuits that
breathing rhythms relay auditory
Tone of body is
regulated here: info from ears to
areas in forebrain
-posture, (where this
alertness and sensory input will
be processed and
Its BIGGEST part
-resp for the
and balance, and
sounds you hear, &
from your various sensory systems.
1. What is the cortex? –is the outermost covering of an organ.
What are the properties of the cortex?
Thin for forebrain, averaging 3mm thick, but still makes up 80% of
the brain. Analogy: if stretched out flat, it would be 2 sq. feet.
BUT, cortex is actually CRUMPLED and ―jammed‖ to fit in
skull, producing wrinkles the convolutions.
Some valleys between the wrinkles are deep
grooves, dividing brain into different sections.
The deepest groove is the LONGITUNAL fissure, running lengthwise, separating the LEFT
cerebral hemisphere from the RIGHT cerebral hemisphere…these hemispheres constitute the
major part of the FOREBRAIN in us. (Re: forebrain is what we see, remember? Underneath
forebrain is midbrain and hindbrain)
-The other fissures are
1. Lateral fissure: (going across; separating top from bottom) and 2.Central fissure, (separating
front from back)].
They divide the cortex, in EACH hemisphere into 4 lobes. -Use textbook diagrams to visualize this
properly. These divisions occur on both sides of
the cerebral hemispheres, concurrently.
-forms front of brain, is right behind the forehead
-forms brain’s topmost part
Both frontal and parietal lobe are divided by central fissure in each hemisphere.
The BOTTOM EDGE of frontal lobe is at LATERAL FISSURE, and below lateral fissure are
At back of brain, connected to parietal and temporal lobe, are occipital lobes.
Q) What are subcortical parts of forebrain?
1. THALAMUS (fx: is a relay station for almost all sensory information going to cortex
2. HYPOthalamus (underneath thalamus) fx: controlling motivated behaviours like eating,
3. Limbic system surrounds thalamus and hypothalamus and is interconnected. Limbic
system consists of amygdala and hippocampus (both are in temporal lobe & subcortical)
Fx: needed for learning and memory, and for making of new memories (PROOF: H.M.
developed amnesia after removal of these structures).
People have thorough and longer-lasting remembrance for emotional events vs. non-
emotional ones (memory is even stronger when amygdala is activated while witnessing
this emotional event).
If amygdala damaged, this particular memory advantage diminishes.
What is Lateralization?
all brain structures-cortical and subcortical-occur in pairs.
o Ex) There is a left side amygala and a right side amygdale
o Ex) There is a left side occipital cortex and right side occipital cortex
Are left side and right side parts completely symmetrical?
Roughly same, in most domains, EXCEPT there are DIFFERENCES in function,
between the same left-side and right-side parts.
Connections: -both haves work together, functioning of one side is integrated with other side, through
COMMISSURES (thick bundles of fibres, carrying info back and forth between both
hemispheres).An example of a commisure (the LARGEST) is corpus callosum
Corpus callosum used to be cut in extreme cases of epilepsy, resulting in split brain
patient. (communication between both halves limited) SEE FIG 2.5
From these patients we learnt: that both halves are specialized in their unique ways.
Left side-Language Capacities, Right Side-needed for spatial judgement tasks.
BUT STILL: both halves are partners in almost all mental tasks, each side contributing their own
specialized skills for overall task. It’s n ever left side of brain versus right side of brain. They are
buddies. Complex skills (ex: creativity and intuition) depend on WHOLE brain, not just one
Neuropsychology: study of brain’s structures and how they relate to brain function.
CLINICAL Neuropsychology: specifically, study of brains with damage, to learn more about
functioning of intact brains.
The pattern we see: particular symptoms we see in brain damaged patients, depends on site of
LESION: particular site of damage in brain. (ex: lesion in hippocampus
produces memory problems, and not language problems)
Consequences of brain lesions IS FURTHER SPECIFIC to WHICH hemisphere is damaged.
Ex) Damage to frontal lobe, left side: disruption of language use. BUT, damage to right side
does not have this effect.
The next page chart shows how a neuroscientist can study brain with technology.
N E U R O I M A G I N G T E C H N I Q U E S (all 4 give 3D image of brain)
MRI (PAGE CT (Computerized PET (Positron Emission fMRI (PAGE
42) Axial Tomography) (PAGE 45, 47)
How does it -uses magnetic -gives brain -introduce a tracer -closely related
work? properties of structure via x- substance (ex. Glucode- to MRI.
atoms in brain rays; body’s fuel) -shows brain
tissude to give
detailed pic of Primary data: x- These tracer activity like
rays molecules PET.
brain are tagged
with low -shows oxygen
dose of content of
radioactivity, blood flowing
allowing the through each
scan to brain region.
We get stable results in BOTH MRI and CT brain, to see accurately level
scans, because brain structure stays
consistent (as long as no tumor which tissues of neural
growth/accident.) use more of activity in each
it, and which region.
less, during a
Whereas, fMRI and PET scans tell us the pattern of
activation; the results depend on which TASK you were
performing @ time of task. This cements that different
brain areas perform different functions….brain is
Neurons do brain’s main work. They vary in size, shape, functions, but usually they
communicate with each other through chemical signals called NEUROTRANSMITTERS.
Activated neurons release transmitters, which further activates/deactivates immediately
adjacent neurons (these neurons ―receive‖ the chemical message). They can send the
message further, to other neurons.
But, there is also important messaging that goes on WITHIN a neuron itself..how the
message travels through the neuron, from the input end (most sensitive to receiving
sisgnal) to the output end.
How does this happen? Via electrical pulse; (b/c of flow of ions (atoms with charges-+ or -, in and out of
Collectively, considering the brain has ONE TRILLION neurons, when they are
active at the same time, the current generated can be detected by electrodes placed on
your scalp’s surface.
This is ELECTROENCEPHALOGRAPHY (― records the voltage changes that
happen at the scalp, as a reflection of what’s going on underneath). This technique
produces an electroencephalogram (EEG)
EEG’s study broad rhytms in brain’s activities (ex: rhythms in different sleep
stages See pg 44). EEG’s