Download Introduction to Cognitive Development 2012

Cognitive psychology
Introduction to cognitive psychology
Emma Mcnally
SFU WS 2012
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Mental processes involve interpretation and/or transformation of info that obey well-defined principles
to produce specific output when given a specific input
– Processes operate on representations
– Serial processing – specific sequence of steps, where each step’s sequence depends on the
previous step;
i. Starting a car and driving to UH is sequential
– Parallel – several operations occurring at the same time
i. Keeping a conversation flowing: you are listening to your friend, generating your own
response, watching your friend’s gestures etc.
4. Goal of cognitive psychology: establish general principles of the mind
– General principles of the mind: processes and representations as they relate to attention, memory,
perception, language comprehension and generation etc. in all people
i. We may have very different memories about our childhoods but the process of
remembering should be the same for all people
– Age, gender, ethnicity, socio-economical status are not considered in “pure” cognitive
psychology studies. Researchers typically study healthy normal adults (i.e. above 18 and under
50)
– Studies with lesion patients, children or older adults are usually informative about general
principles of the mind but these populations in and of themselves are not of predominant interest
to cognitive scientists
• 1. Cognitive psychology: study of the human mind and mental
activity (i.e. how we reason, decide,produce and comprehend
language etc.)
• – Describes acquisition, storage, transformation and use of
knowledge
• – Interest in representations and processes
• 2. Mental representation: physical state that conveys info,
specifying an object, event, or category or its characteristics; serves
to store info
• – Form – means by which info is conveyed (e.g. visual, auditory)
• – Content – meaning of what is being conveyed
• – For example: receiving a phone call about a football game score
• i. Form: phone call
• ii. Content: football game score
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Cognitive science: An extension of information processing where many disciplines work together to
understand how the human mind functions
– Psychology: to understand human behavior
– Computer Science: to understand computation
– Neuroscience: to understand how the brain works
– Philosophy: to understand the limits of our theories
– Linguistics: to understand the structure of language
– Anthropology: to help separate characteristics of the mind from characteristics of culture
– Researchers often collaborate and/or work across these disciplines
6. Note that cognitive psychology refers to theories of information processing and involve
experiments with behavioral data (i.e. how people perform on various tasks) while cognitive
neuroscience takes cognitive psychology theories and looks at what the brain is doing while people
are performing various tasks
– In short, cognitive psychology = behavior, cognitive neuroscience = behavior and corresponding
brain activity
Functional Human Neuroanatomy
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Brain activity arises from activity in neurons
a. There are different sizes and shapes of
neurons but basic parts and functions are
the same
b. Dendrites and cell body receive input from
other neurons
c. Axon sends output to other neurons
d. Neurons communicate with other neurons
by releasing and accepting
neurotransmitters which either activate or
inhibit neurons
e. If excitation of a neuron is higher than
inhibition, neuron “fires” and sends a
signal down its axon to another neuron
Neurons and how they work
• http://www.youtube.com/
watch?v=FR4S1BqdFG4&fea
ture=player_embedded#!
Central nervous system
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Central nervous system
a. Spinal cord
i. Sensory info to brain from muscles
ii. Motor commands from brain to muscles
b. Brain: start from evolutionarily oldest to
newest structure in brain.
Cerebellum
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Brainstem includes pons, medulla, reticular
formation. Reticular formation is important
for arousal, attention, sleep. Brainstem is
involved in coordinating basic living
functions
1. Balance, alertness, heart rate, blood
pressure and temperature (less advanced
functions than those controlled by
hypothalamus)
2. Coordination center which keeps
everything stable
3. Info relay station between brain and
spinal cord
4. A person is considered dead when there
is no response from the brainstem
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Cerebellum, literally “little brain”
1. Contains as many (or even more) neurons
than brain and spinal cord put together
2. Involved in indirect control of
movements by influencing descending
motor commands from brain to spinal cord
3. Damage results in symptoms of intoxication
4. We really know very little about the functions of the cerebellum
iii. Midbrain. The textbook places midbrain together with the brainstem,
whereas I teach it as a
• separate structure by itself. Both approaches are correct but for ease of
remembering, when you
• think of midbrain, I want you to think of the superior and inferior colliculi,
which are involved
• in sensory processing.
• 1. Superior colliculus:
Important for vision; eye
movements
• 2. Inferior colliculus:
Important for
• audition
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Hypothalamus
1. Regulates body functions
necessary for survival (more
advanced than brainstem but
also involved in same functions
as brainstem by regulating those
functions via hormones)
a. Salivation, feeding, sex,
circadian rythms
v. Thalamus
1. Relay signals from one cortex
area to another
2. A lot of sensory
processing/relay
a. Thalamus consists of numerous nuclei, several of which are devoted to sensory
processing only; lateral geniculate nucleus (LGN is for vision, medial geniculate
nucleus is for audition
• Basal ganglia: Group of structures and nuclei involved in
complex movement planning and
• habit formation
• vii. Limbic system is involved in forming memories,
experiencing pleasure, motivational and
• emotional activities and contains:
• 1. Reticular formation (from brainstem)
• 2. Hypothalamus
• 3. Thalamus: sensory inputs
• 4. Nucleus accumbens: rewards
• 5. Amygdala
• 6. Hippocampus: memory
Limbic system
• Cortex: evolutionarily
newest “structure”
• 1. Thin grey outermost layer
of the brain
• 2. Gyrus – bulge on the
cortex
• 3. Sulcus/fissure – groove
between gyri
• 4. Cortex is divided into four
major lobes
4 major lobes
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a. Occipital lobes are at the back of the
brain
i. Processing of visual input
ii. 60% of monkey’s cortex is
devoted to visual processing
b. Temporal lobes are behind our ears
i. Higher order visual processing
(i.e. face recognition)
ii. Memory consolidation and
storage (this function also
includes subcortical structures, such as hippocampus)
iii. Auditory processing
iv. Language comprehension (Wernicke’s area)
c. Parietal lobes: top back of our heads
i. Representation of space
ii. Attention
iii. Contain somatosensory cortex
d. Frontal lobes: right above the eyes
i. Plan sequences of behaviors
ii. Reasoning, decision making
iii. Speech production (Broca’s area)
iv. Emotion, personality
v. Contains primary motor cortex
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Brain: 2 cerebral hemispheres (halves
of
brain) are connected via corpus
callosum.
The left hemisphere is (almost) a mirror
image of the right hemisphere
ii. Some structures are bigger/smaller
iii. Some functions are more expressed
in one hemisphere than others (i.e.
language processing in
the left hemisphere for over 90% of
humans; spatial information processing
in right
hemisphere)
iv. Key point: there are two amygdalas,
two LGNs etc.
Directional terminology: finding your way
around the brain
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Anterior/Rostral: toward the nose
end
• Posterior/Caudal: toward the tail end
• Dorsal: toward surface of the back
(spine) or top of the head
• Ventral: toward surface of
chest/stomach or bottom of the head
• Lateral: toward the sides of brain,
left or right
• Medial: toward the middle of brain
• Superior: toward the dorsal surface
of head (humans)
• Inferior: toward the ventral surface
of the head
Terms in action:
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Frontal lobe is anterior to the occipital lobe
• Occipital lobe is posterior to the frontal lobe
• Parietal lobe is dorsal to the temporal lobe
• Temporal lobe is ventral to the parietal lobe
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More terms:
• Bilateral: both sides of brain
• Contralateral: opposite side of brain from a given
reference point
– I.e. inputs from the left visual field are
processed in the right hemisphere; inputs
from the right visual field are processed in the
left hemisphere
• Ipsilateral: same side of brain as a given reference
point
– Left eye is ipsilateral to left LGN
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How we study cognition: Methodology
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Converging evidence: Different methods are often combined to establish dissociations, double
dissociations, associations about the processes, properties of processes and brain areas involved in
the processes of a specific mental activity
a. Different methods are combined to establish dissociations, double dissociations, and
associations
i. Dissociation: establish that an activity or a variable affects the performance of one task
(or aspect of one task) but not of another
1. Hypothesis: Occipital cortex is crucial for visual perception
2. Test: Lesion occipital cortex, give visual and auditory perception test
3. Result: visual perception is impaired but auditory perception is not
ii. Double dissociation: an activity or variable affects one process but not another and a
second activity or variable has the reverse properties.
1. Hypothesis: Occipital cortex is crucial for visual perception
2. Test: Lesion occipital cortex, lesion auditory cortex, give visual and auditory
perception test
3. Result: visual perception is impaired with occipital lesion but auditory perception
is not; auditory perception is impaired with auditory cortex lesion but visual
perception is not
• iii. Association: the effects of an activity or
variable on one task are accompanied by effects
• on another task
• 1. Dual task: counting backwards by threes and
reading words is slower than either task done
alone
• 2. Some of the processes and/or representations
between these two tasks overlap.
Behavioral methods: what we typically measure
• a. Reaction time (RT) data – speed of
response; used very often
• b. Number of correct items – used very often,
also in conjunction with RT
• c. Judgments/protocol
Neuroimaging - Correlates behavior to a pattern
of brain activity; does not mean cause and
effect
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a. What functions are performed?
i. Is this a language comprehension or language generation task?
b. Where are they performed?
i. Issue of spatial resolution – how well can brain activity be
localized? Poor spatial
• resolution means poor ability of a tool to locate where activity is
originating from. I.e.compare ability to detect activity in frontal or
occipital lobes versus ability to detect activity in the superior
colliculus (a much smaller structure than lobes)
• c. When does the activity occur?
• i. Issue of temporal resolution – how well can changes in brain
activity be detected? How fast can those changes be detected?
Neuroimaging approaches
• a. EEG: electroencephalogram(recording of brain waveselectrical activity of brain)
• b.MEG: magnetoencephalography (measures magnetic
fields from neuronal activity
• c. PET: positron emission tomography (3D picture of
functional processes in the body)
• d. MRI: Magnetic resonance imaging
• i. MRI gives a nice clear picture of brain structure
• ii. fMRI (functional magnetic resonance imaging)gives an
activation map for the brain
• 1. MRI and fMRI images are overlaid and reported together
in all scientific papers
DOT (diffuse optical imaging)
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PET/fMRI and DOT are all built on the idea that an active brain site will require more
glucose and oxygen to supply energy to the neurons in that site. Therefore, an active
brain area will attract more blood and thus it will attract more of the radioactive
substance (used in PET), more oxygen (detected by fMRI) or more hemoglobin (as
measured by DOT). Although these different techniques measure a different component
present in the blood, the temporal resolution of these three approaches is almost
equivalent because again, they all rely on the blood flow. Because it takes several
seconds for the blood to flow to an active site in the brain, the temporal resolution,
therefore, is fairly poor when compared to the EEG temporal resolution (which is
excellent). Notice that the table in the book indicates that the temporal resolution of
optical imaging can be as bad as several minutes – for the purposes of the quiz/exams
think of DOT resolution as that of PET/fMRI, which, again, is poor.
• Most studies generate brain images to indicate where activity occurred.
Each brain can be viewed from three different planes that are taken
directly from anatomy: sagittal, coronal and horizontal planes. These
planes tell us from what position we’re looking at the brain:
• i. Sagittal: looking from the side
• 1. Brain “sliced” between the two eyes
• 2. Mid-sagittal cut divides the brain in two equal halves (hemispheres)
• ii. Horizontal: looking either directly from top or bottom; such cuts are
parallel to the ground
• 1. Think of taking off the scalp
• iii. Coronal: looking either directly from front or back; such cuts are
perpendicular to the ground
• 1. “Slice” separates the two eyes from the two ears
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Apply the planes on the left to the brain (rather than
the body). MRI images are examples of these cuts in
human subjects.
• Sagittal (mid-sagittal here)
cut
• Frontal lobe
• Corpus callosum
• Thalamus
• Occipital lobe
• Cerebellum
• Pons
By looking at the slide with structures that
are visible in the cut you can determine
where the brain was cut: right between
the eyes or between the eye and the ear.
We need to cut the brain in different
places because the brain is 3-D and we
can’t see all brain structures if we always
cut right between the eyes or right above
the ears (compare how different the
frontal and occipital lobes, thalamus and
corpus callosum look in these cuts below).
Research papers often report several
horizontal/coronal/sagittal cuts to indicate
where activity is originating from. The
type of a cut, its thickness and frequency
is chosen by researchers.
Ways to infer what brain does without directly
measuring brain activity
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a. Lesion studies
i. Usually . with human patients suffering brain damage or lab experiments using animals
ii. If an area has a lesion and the person shows a specific deficit, then that area probably has
something to do with that function.
iii. Could be hard to interpret data since locations of lesions across humans vary greatly and
patients that suffer brain damage typically suffer brain damage to more than one area
b. TMS (Transcranial magnetic stimulation)
c. “Freeze” a given area with special chemical and test performance on a behavioral task; compare
to the performance in “non-freeze” condition; reversible, invasive & done with animals only
d. Give drugs that target a given brain region and test performance on a behavioral task; invasive,
used with humans and animals
The end
• Congratulations you survived the
introduction.