lecture 3: cognitive neuro methods

Question 1

Electroencephalography (EEG)

Answer 1

An EEG is a test that measures your brain waves and helps detect abnormal brain activity. The results of an EEG can be used to rule out or confirm conditions, such as epilepsy, a brain tumor, or a stroke.

Question 2

Magentoencephalography (MEG)

Answer 2

Magnetoencephalography (MEG) is a noninvasive test that neurologists and neurosurgeons use to help plan brain surgeries for epilepsy and tumor removal. MEG maps out the sensory areas of your brain and can pinpoint the exact location where seizures originate

Question 3

Diffusion Tensor Imaging (DTI)

Answer 3

Diffusion Tensor Imaging (DTI) is a technique that detects how water travels along the white matter tracts in the brain (Fig. 2). White-matter tracts connect different parts of the brain and must be protected during surgery.

Question 4

Single Cell Recordings

Answer 4

Single-cell recording is a technique used to observe changes in voltage or current in a single neuron

Single cell recording has the highest resolution of all brain imaging techniques. It provides much information about the activities of a few neurons, but it has a low generalizability. Up to fifty cells can be recorded at once, and with this technique it is also possible to follow the activity of a neuron over time.

Single cell studies are not very helpful for studying the human brain, since it is too invasive to be a common method. Hence, this method is most often used in animals. There are just a few cases in which the single-cell recording is also applied in humans.

Question 5

Transcranial Direct Current Stimulation (tDCS)

Answer 5

portable, wearable brain stimulation technique that delivers a low electric current to the scalp

Transcranial direct current stimulation (tDCS) is a popular brain stimulation method that is used to modulate cortical excitability, producing facilitatory or inhibitory effects upon a variety of behaviors

On the other hand, this very ease of use lends itself to a high potential for misuse, such as recreational use, unsupervised medical use, and unethical use. Its long-term effects are also not well established.

Question 6

Cognitive Psychology

Answer 6

*Relies on cognitive testing of healthy individuals

*Theories refers to
hypothetical mechanisms:
underlying mental
processes
and representations

*Manipulation of experimental variables plays a critical role in
generating results and testing theories

Question 7

what do cognitive psychologists do

Answer 7

Cognitive psychologists ask
people to perform tasks, and measure reaction time and/or
percent correct. Why?

We want to know what factors CHANGE how fast or accurate you are, and we want to CONTROL
them.

Question 8

correlation

Answer 8

a linear relationship between two
variables

Question 9

positive correlation:

Answer 9

as one variable increases,
the other variable increases

Question 10

negative correlation:

Answer 10

as one variable increases,
the other variable decreases

Question 11

causation

Answer 11

producing an effect (a “cause” is
something that produces a particular effect).

Question 12

if you observe a correlation (e.g., a
positive or negative relationship), can you make
a conclusion about causation?
Correlation vs. Causation

Answer 12

no

Two possible errors in causal reasoning from a
correlation (good reasons not to do it)

Wrong Direction: even if one causes the other, you
can’t say whether A causes B or vice versa.

Missing Third Variable: it’s always possible that
there is an unmeasured third variable that is
actually the underlying cause for both of your
measured variables

Question 13

Correlation vs. Causation

Answer 13

Experimental control/manipulation provides a
much stronger basis for drawing conclusions
about causation

-a relationship between two variables does not tell
you which variable is the causal variable.

-only controlled experimental manipulations give
you the ability to determine which variable is
causal.

-other, hidden third variable (C) could be causing
changes in both A and B

Question 14

Franz Josef Gall
1758-1828

Answer 14

Phrenology

Observed in medical school, that
classmates with bulging eyes had
great verbal memories.

Later theorized verbal memory was localized in front of brain;
more developed memory caused
enlarged frontal lobe, which caused bulging
eyes.

Extended this logic to size of bumps
on the skull.

Question 15

Phrenology

Answer 15

Hypothetical psychological
characteristics localized to
different brain regions.

Size of bumps on skull could tell you which functions were highly developed in a particular individual

Question 16

why was phrenology bad

Answer 16

-Often considered a case study in bad
science (so-called pseudoscience)

• But the idea of localization of function is important
• Bad methodology - Gall seemed to be relying on something like his “inner ding”
• Really just needed the right methods!

Question 17

Paul Broca (1824-1880)

Answer 17

a region of the brain concerned with the production of speech, located in the cortex of the dominant frontal lobe. Damage in this area causes Broca’s aphasia, characterized by hesitant and fragmented speech with little grammatical structure.

Question 18

Carl Wernicke (1848-1905)

Answer 18

Damage to Wernicke’s area can lead to disorders associated with speech and language such as Wernicke’s aphasia. This condition causes difficulty with understanding language and forming meaningful sentences

Question 19

Vascular disorders

Answer 19

stroke, hemorrhage

Question 20

Causes of neurological/neuropsychological problems:

Answer 20

Vascular disorders: stroke, hemorrhage

Tumor

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

Question 21

Tumor

Answer 21

a swelling of a part of the body, generally without inflammation, caused by an abnormal growth of tissue, whether benign or malignant.

Question 22

Alzheimer’s

Answer 22

A progressive disease that destroys memory and other important mental functions.
Brain cell connections and the cells themselves degenerate and die, eventually destroying memory and other important mental functions

Neurofibrillary tangles and amyloid plaques

Question 23

Parkinson’s

Answer 23

(loss of dopamine neurons)

Question 24

Huntington’s

Answer 24

(basal ganglia atrophy)

Question 25

cte

Answer 25

Chronic Traumatic
Encephalopathy (CTE), indicated by presence of tau
protein (brown stains below)

Question 26

Neurology and Neuropsychology method

Answer 26

-Look at diseased/damaged brains

-Assess mental abilities through cognitive testing

-Attempt to link specific cognitive deficits to damage in
specific brain regions

Question 27

Single dissociations

Answer 27

Patient A can do Task X but not Y

Question 28

Double dissociations:

Answer 28

Patient A can do Task X but not Y, plus Patient B can do TasK
Y but not X

Question 29

Advantages of Double dissociations:

Answer 29

• “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).

Question 30

Disadvantages of Double dissociations:

Answer 30

-Not a controlled experiment

-Damage not always localized; many functions can be
impaired

-Neuropsychological tests based on narrow
demographic samples; more diverse populations need to be included,
cultural factors assessed (Byrd & Rivera-Mindt, 2022)

-Can you make inferences about normal function?
-Plasticity, recovery (repaired brain not = normal brain)

Question 31

Transcranial Magnetic Stimulation

Answer 31

create temporary ‘lesion’ in healthy individuals

Question 32

Advantages of Transcranial Magnetic Stimulation

Answer 32

-high spatial resolution: changes neural activity in a
spherical area of approx. 1 cm3

-high temporal resolution

-can be used repeatedly

-provides information about causal role of brain area in particular perceptual/cognitive/motor function.

Question 33

Disadvantages of Transcranial Magnetic Stimulation

Answer 33

-mainly restricted to brain regions close to the skull

-holding the coil in place not easy

Question 34

Functional Imaging

Answer 34

Functional imaging tells us about what the brain
does – the brain in action – whereas structural
imaging provides a static look at the structure of
the brain.

Both computed tomography (CT) and magnetic
resonance imaging (MRI) are used for structural imaging of the brain, but MRI provides a much
clearer and detailed picture

Question 35

Functional imaging

Answer 35

tells us about what the brain
does – the brain in action

Question 36

structural
imaging

Answer 36

provides a static look at the structure of
the brain

Question 37

computed tomography (CT)

CT Scan vs. MRI:

Answer 37

A CT scan is a diagnostic imaging exam that uses X-ray technology to produce images of the inside of the body

What’s the Difference? And How Do Doctors …
CT scans take a fast series of X-ray pictures, which are put together to create images of the area that was scanned. An MRI uses strong magnetic fields to take pictures of the inside of the body. CT scans are usually the first choice for imaging. MRIs are useful for certain diseases that a CT scan cannot detect

Question 38

magnetic
resonance imaging (MRI)

Answer 38

Magnetic resonance imaging, or MRI, is a noninvasive medical imaging test that produces detailed images of almost every internal structure in the human body, including the organs, bones, muscles and blood vessels. MRI scanners create images of the body using a large magnet and radio waves.

Magnetic Resonance Imaging (MRI) is a non-invasive imaging technology that produces three dimensional detailed anatomical images.

Question 39

positron emission tomography (PET)

Answer 39

Positron emission tomography is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption.

Question 40

functional magnetic resonance imaging (fMRi)

Answer 40

Functional magnetic resonance imaging (fMRI) measures the small changes in blood flow that occur with brain activity. It may be used to examine which parts of the brain are handling critical functions, evaluate the effects of stroke or other disease, or to guide brain treatment.