RESEARCH METHODS (5)

Question 2

Why is a test of general intelligence included in neuropsychological testing?

Answer 2

Helps interpret results of subsequent tests.

Can suggest patterns of brain dysfunction (e.g., low verbal comprehension → possible left hemisphere damage).

Commonly uses Wechsler Adult Intelligence Scale (WAIS).

Question 3

What are the limitations of WAIS for memory assessment?

Answer 3

Subtests like information (general knowledge) and digit span (short-term memory) often fail to detect serious memory deficits.

Memory problems are usually reported by patient or family rather than detected by WAIS.

Question 4

How is language assessed in a neuropsychological test battery?

Answer 4

WAIS verbal subtests can indicate language deficits.

If WAIS not used: Token Test: 20 tokens varying in shape, size, and color; patient follows increasingly complex instructions.

Question 5

Why is testing language lateralization important?

Answer 5

Determines which hemisphere is dominant for language (usually left).

Useful for interpreting other tests.

Critical before surgery near cortical language areas to avoid damage.

Question 6

What are the two main tests of language lateralization?

Answer 6

Sodium Amytal (Wada) Test: Anesthetic injected into one carotid artery; ipsilateral hemisphere is temporarily anesthetized. Dominant hemisphere → temporary mutism.

Dichotic Listening Test: Different sequences of digits presented to each ear; patients report more digits from the ear contralateral to the dominant hemisphere.

Question 7

Key difference between Sodium Amytal and Dichotic Listening tests?

Answer 7

Sodium Amytal: invasive, only for medical reasons (surgery prep).

Dichotic Listening: noninvasive, can be used in research and clinical settings.

Question 8

What is the purpose of specific neuropsychological tests?

Answer 8

To clarify the nature of general problems revealed by the common test battery.

Thousands of tests exist; selection depends on the patient’s deficits.

Question 9

What key memory questions are addressed after detecting memory impairment?

Answer 9

Does it involve short-term memory, long-term memory, or both?
Are long-term deficits anterograde, retrograde, or both?
Are long-term deficits semantic (world knowledge) or episodic (personal experiences)?
Are deficits explicit (conscious) or implicit (unconscious), or both?

Question 10

How is implicit memory assessed in amnesic patients?

Answer 10

Repetition priming tests:
Patients study a list of words without being asked to remember them.
Later, they complete word fragments (e.g., “pu_p_ _” for “purple”).
Amnesic patients perform as well as controls implicitly but have no explicit memory of the words.

Question 11

How are language deficits further investigated?

Answer 11

Tests target three capacities:
Phonology – rules governing sounds.
Syntax – grammar of the language.
Semantics – meaning of language.
Brain damage can affect one capacity but not others, so all must be tested.

Question 12

How is reading ability assessed in neuropsychological testing?

Answer 12

• Tests differentiate patterns of reading disruption:
  Some dyslexic patients follow rules but fail irregular words (e.g., come, tongue).
  Others remember familiar words but cannot apply pronunciation rules to new/nonwords (e.g., trapple, fleeming).

Question 13

What is the main goal of cognitive neuroscience?

Answer 13

To identify brain regions or networks that mediate specific cognitive processes.

Question 14

Why is simple functional imaging not enough to isolate specific cognitive processes?

Answer 14

Because brain activity recorded during a task includes all processes, e.g., seeing, reading, speaking—many of which are unrelated to the process of interest.

Question 15

How does paired-image subtraction work?

Answer 15

Obtain brain images during two different tasks that differ in only one cognitive process.

Subtract the brain activity of one task from the other to isolate activity associated with the specific process.

Question 16

What is the default mode network?

Answer 16

The DMN is a set of brain structures that remain active when a person is at rest and not engaged in a task. It reflects the brain’s default activity—mind-wandering, self-reflection, daydreaming. Activity is usually reduced during focused cognitive or behavioral tasks.

Question 17

Which structures are part of the DMN?

Answer 17

Four main cortical areas: Medial prefrontal cortex (mPFC), Medial parietal cortex, Lateral parietal cortex, Lateral temporal cortex.

Question 18

What is a mean difference image?

Answer 18

When using PET or fMRI, random brain activity (“noise”) can interfere with interpreting cognitive processes. Signal averaging solves this by averaging multiple difference images from repeated tests for the same subject or multiple volunteers. Mean difference image: emphasizes common brain activity across subjects and reduces noise from random activity.

Question 19

Limitations of mean difference images?

Answer 19

Individual variability: averaging can obscure unique activation patterns. Experience-dependent changes: cortical areas controlling a function can shift over time within an individual.

Question 20

What is functional connectivity?

Answer 20

The study of how multiple brain regions work together by examining parallel patterns of activity over time.

Question 21

Types of functional connectivity?

Answer 21

Extrinsic FC: FC measured during a task or stimulus presentation. Intrinsic FC: FC measured during resting-state fMRI (R-fMRI).

Question 22

What is the functional connectome?

Answer 22

The comprehensive characterization of functional connectivity networks associated with each cognitive process or behavior.

Question 23

What are species-common behaviors?

Answer 23

Behaviors displayed by virtually all members of a species, or at least all of the same age and sex. Examples: grooming, swimming, eating, drinking, copulating, fighting, nest building.

Question 24

What is the open-field test and what does it measure?

Answer 24

A test where a subject is placed in a large, barren chamber. Measures general activity, excrement dropped (bolus count), and thigmotaxis (tendency to stay near walls). Low activity and high bolus count indicate fearfulness.

Question 25

How does repeated exposure affect rat behavior in the open-field test?

Answer 25

Fearfulness usually declines with repeated exposure to the same open field.

Question 26

What is the colony-intruder paradigm?

Answer 26

A test of aggressive and defensive behavior where the dominant male rat of a colony is exposed to a smaller intruder. Dominant behaviors = aggression; intruder behaviors = defense.

Question 27

What are examples of aggressive behaviors in rats?

Answer 27

Piloerection, lateral approach, flank/back biting.

Question 28

What are examples of defensive behaviors in rats?

Answer 28

Freezing, boxing (rearing/pushing), rolling over, resistance to handling.

Question 29

What is the elevated plus maze and how is it used?

Answer 29

A plus-shaped maze with two open arms and two closed arms, elevated 50 cm above the floor. Measures anxiety based on time spent in open vs. closed arms.

Question 30

How do anxiolytic drugs affect the elevated plus maze?

Answer 30

They increase the proportion of time rats spend in the open arms.

Question 31

How is male rat sexual behavior measured?

Answer 31

Number of mounts to intromission, number of intromissions to ejaculation, and post-ejaculation interval.

Question 32

What is the lordosis posture in female rats and how is it measured?

Answer 32

Lordosis = hindquarters up, back bent in a U, tail deflected. Measured as lordosis quotient = proportion of mounts eliciting lordosis.

Question 33

What is Pavlovian (classical) conditioning?

Answer 33

Pairing a neutral conditional stimulus (CS) with an unconditional stimulus (US) so the CS eventually elicits a conditional response (CR). Example: tone + meat → salivation.

Question 34

What is operant conditioning?

Answer 34

Behavior is modified by consequences: reinforcement increases response, punishment decreases response.

Question 35

What is the self-stimulation paradigm?

Answer 35

A type of operant conditioning where animals press a lever to deliver electrical stimulation to brain sites (pleasure centers).