Lesson 4 Flashcards
The field of ________ is based on the idea that perception and thought employ mental representations that undergo transformations as they are used.
cognitive psychology
What are the two possible errors in causal reasoning from a correlation?
wrong direction
missing third variable
what are the 4 methods for measuring the brain?
lesion, stimulation activation/deactivation, electrophysiological/magnetic recordings, brain imaging
what is a lesion study?
Psychological/behavioral testing of patients with neurological
disorders or damage to understand the organization
of mind and brain
what are two types of lesion study cases?
single case studies
group studies
what do lesion studies establish?
Establish nature of impairments following focal
lesions
true or false? if false, correct the statement
as a scientist, you can perform a single and or a double disassociation
true
what do patient’s with lesion in Broca’s area experience?
difficulty processing language; could understand language well but had trouble speaking fluently
what do patient’s with lesion in Wernicke’s area experience?
difficulty comprehending information/language; could speak fluently but words meant nothing
what are the advantages of lesion studies?
- “Natural experiment”: suggests causal role for brain
area in particular cognitive function. - Double dissociations provide strong evidence for
separable processes (e.g. Broca’s versus Wernicke’s,
production vs. comprehension)
what are the disadvantages of lesion studies?
-Not a controlled experiment
-Damage not always localized; many functions can be
impaired
-Neuropsychological tests based on narrow demographic
samples
-Can you make inferences about normal function?
-Plasticity, recovery (repaired brain not = normal brain)
how would you perform a temporary “lesions”? (2 ways talked about in lecture)
cortical stimulation and transcranial magnetic stimulation
this image is an example of _____
cortical stimulation
this image is an example of _____
deep brain stimulation
what was the work of Wilder Penfield? What was his contribution to the field?
used electrical stimulation to map out functions for different areas in the brain
what happens during transcranial magnetic stimulation (TMS)? who can TMS be done on?
Magnetic field outside the skull induces electric field inside skull that can disrupt normal brain activity; on healthy voluntary humans
what are the advantages of transcranial magnetic stimulation (TMS)?
-high spatial resolution
-high temporal resolution (very brief)
-can be used repeatedly
-provides information about causal role of brain area in particular
perceptual/cognitive/motor function
what are the disadvantages of transcranial magnetic stimulation (TMS)?
-mainly restricted to brain regions close to the skull (you cant reach deep brain areas like the hippocampus)
True or false? if false, correct the statement
you can measure causation with TMS
true
what happens during electrophysiological recordings (EEG)?
an investigator measures response properties of single cells by inserting a thin electrodes into an animal’s (or human’s) brain and record extracellularly to determine which experimental
manipulations change the cell’s response
What is event-related potential (ERP)?
the measurement of a specific event and see how it changes relative to another event
what happens during magnetoencephalography (MEG)?
measures magnetic signals generated by neural activity
what are the advantages of EEG and MEG?
- usually non-invasive
-high temporal resolution
-can be used repeatedly
what are the disadvantages of EEG and MEG?
-poor spatial resolution, don’t always know where signal is generated
The technique known as ________ can be used to induce virtual lesions in humans.
TMS (transcranial megnetic stimulation)
What is an advantage of MEG (magnetoencephalography) over EEG (electroencephalography)?
With MEG, magnetic fields are not distorted by brain tissue and the skull so there is better localization
For a researcher to provide evidence that a brain area and cognitive function are associated, they could use a _____________ dissociation, however, to provide more substantial evidence about the function and function localization, they would need a ______________ dissociation.
single; double
what are the two primary functional imaging techniques used in humans?
positron emission tomography (PET)
functional magnetic resonance imaging (fMRI)
what does PET imaging measure?
measures local variations in blood flow
how many tasks are given during a PET scan?
two
true or false? if false, correct statement
signal is never relative to a control condition
false; signal is always relative to a control condition
what are MRIs used to study?
to see details of brain anatomy
what is one big advantage to PET scans over fMRI?
you can measure things like neurotransmitter function
what are fMRIs used to study?
brain function
what are some main points for MRIs?
- strong magnetic field
- protons align with magnetic field
- radio wave perturbs alignment
- detectors pick up the signal of protons returning to orientation of
magnetic field - different tissues have diff densities of protons (gray/white matter)
- changes in blood flow can also affect the local magnetic properties of
tissue, which can be observed as changes in MRI signal (Blood
Oxygenation Level Dependent Signal (BOLD)
in this scan, what makes up the white matter?
myelinated axons
in this scan, what makes up the gray matter?
cell bodies and dendrites of neurons
what is the purpose of fMRIs?
An indirect measure of neural activity
MRIs can also be called ______ MRIs
structural
what is the BOLD signal?
blood oxygen level dependent signal
what is the hemodynamic response function?
the change in blood flow
what is an advanatge of fMRI over PET scans?
PET scans take 30 seconds- 1 minute while fMRI takes a few seconds
what is common between fMRIs and PETs
they share a subtraction logic
what are the advantages of fMRI?
-excellent spatial resolution (1 to 10 mm – PET not as good)
– Better temporal resolution (fMRI – seconds, PET – minutes; both much
worse than eeg/meg)
– Does not require injection of radioactive tracer
– More readily available to researchers broadly
what are the advantages of PET?
Can assess more than blood flow (glucose metabolism, neurotransmitters)
what are disadvantages of all functional imaging methods? (including EEG, MEG)?
They are essentially correlational, can show a region is more or less involved during a
task, but not that it is critical for that task
what is diffusion tensor imaging (DTI)?
Method for imaging fiber tracts(white matter): direction + integrity
what can we do with diffusion tensor imaging DTI?
-Each fiber tract can be represented by a different color
– We can localize different processes to their respective fiber
tracts
– Spot abnormalities found in white matter
– Great art potential
Which neuroimaging technique involves injecting an isotope of oxygen into the bloodstream and using it to measure regional cerebral blood flow?
PET (positron emission tomography)
Which of the following neuroimaging techniques involves manipulating the orientation of protons?
MRI (magnetic resonance imaging)
cognitive neuroscience is a combination of ….
cognitive psychology and neuroscience
what is the stuff of thought?
representations which is the content of thought and how information is stored in the mind
how does this thinking occur?
Process (or operations) which is the manipulation of mental representing, how info is transformed and mental mechanisms
what did Sternberg conclude in his experiment of short term memory?
scanning process appears serial rather than parallel b/c RT increases as memory set size increases
what were two variable thats Sternberg had in his experiment?
an independent and dependent variables
what do experiments allow for?
they allow the investigator to manipulate one variable (independent) to determine the effect on another variable (dependent) to determine the casual relationship
________ describe the relationships between variables, but cannot determine the cause
correlations
in cognitive psychology, what do experimenters prefer?
experimental control
a linear relationship between two variables
correlation
what kind of correlation is this?
as one variable increases, the other variable increases
positive correlation
what kind of correlation is this?
as one variable increases, the other variable decreases
negative correlation
what are two topics in cognitive psychology that are often confused?
correlation and causation
a relationship between two variables does not tell you which variable is the ______ variable
causal
direction of casusality could be …..
1.
2.
3.
- A ——> B
- A <—— B
- A <——> B
what is sometimes missed when determining the changes in both A and B in an experiment?
a hidden third variable (C)
what is the only situation of manipulations the give you the ability to determine which variable is causal?
only controlled experimental manipulations
Find the word:
Disease or damage; intentional lesion – e.g., stroke;
head injury, tumor resection, experimental lesion in animals
Lesion
Find the word:
Non-invasive and invasive – e.g., TMS; deep brain stimulation
with electrodes, and tools to temporarily deactivate neural
tissue (temporary lesions)
Stimulation
Activation/Deactivation
Find the word:
Non-invasive and invasive – e.g., single cell recording, or other
intracranial recording; EEG, MEG (recorded from brain or scalp)
Electrophysiological/
Magnetic Recordings
Find the word:
Structural and functional – e.g., PET; MRI, functional MRI;
Note: These are typically “indirect” measure of brain activity
and structure
brain imaging
what are some causes of neurological/neurpsychological problems:
-Vascular disorders: stroke, hemorrhage
-Tumor, resection
-Degenerative disorders: Alzheimer’s (plaques & tangles), Parkinson’s (loss
of dopamine neurons), Huntington’s (basal ganglia atrophy)
-Viral infection (encephalitis), loss of oxygen (anoxia)
-Head trauma
-Epilepsy, resection of seizure focus
what is one important thing to remember when talking about lesion studies?
the brain being looked at is not healthy
what are two questions ask during lesion studies?
1.Whether a particular brain region is necessary for a specific
cognitive function
2.How information may be represented in the brain
what are we looking for in patients during a lesion study?
a dissociation between impaired/spared cognitive processes
fill in the blanks
Single; double dissociation
fill in the blanks:
Left (orange): Broca’s area
Right (white): Wernicke’s area
what happens during a PET scan?
a tracer is introduced to the bloodstream through injection and the PET scanner detects photons emitted from isotope. The images show blood distribution in the brain and the more “PET counts” = more radiation
true or false? if false, correct the statement
fMRI and MRIs use the different equipment to read out different things
false; fMRI and MRIs use the same equipment to read out different things
these scans are showing an example of what type of imaging?
magnetic resonance imaging (MRI)
the BOLD signal for fMRIs are based on what fact?
- Based on fact that oxygenated and deoxygenated
blood have different magnetic properties
these images are examples of what type of imaging?
diffusion tensor imaging (DTI)
which variable is the manipulated one?
the independent variable
which variable is the event you are evaluating?
the dependent variable
what is the most common application for deep brain stimulation?
a treatment for Parkinson’s disease
The technique known as ________ can be used to induce virtual lesions in humans.
TMS (transcranial magnetic stimulation)
Which neuroimaging technique involves injecting an isotope of oxygen into the bloodstream and using it to measure regional cerebral blood flow?
PET (positron emission tomography)
Which of the following neuroimaging techniques involves manipulating the orientation of protons?
MRI (magnetic resonance imaging)
