the lesioned brain -congneuro wk 2

Question 2

How do selective vowel and consonant spelling impairments support the cognitive neuropsychological approach?

Answer 2

They suggest that the brain has separate neural resources for processing written vowels and consonants, indicating functional independence between the two.

Question 3

Do neural resources for vowel and consonant processing exist in separate brain locations?

Answer 3

Not necessarily—they could reflect different populations of interspersed neurons rather than distinct brain regions.

Question 4

Why can’t we assume that vowel- and consonant-processing neurons have an exclusive function?

Answer 4

The differences might be relative, and without testing other stimuli (e.g., digits), it is unclear if their function is exclusive to vowels or consonants.

Question 5

What is a single dissociation in cognitive neuropsychology?

Answer 5

A single dissociation occurs when a patient is impaired on one task (A) but relatively spared on another task (B).

Question 6

What is a classical single dissociation?

Answer 6

A classical single dissociation occurs when a patient is impaired on Task A but performs entirely normally on Task B compared to a control group.

Question 7

What is a strong single dissociation?

Answer 7

A strong single dissociation occurs when a patient is impaired on both tasks, but is significantly more impaired on Task A than on Task B.

Question 8

how does TMS work

Answer 8

The stimulating coil contains an electric current that generates a magnetic field and this induces a secondary electric current in the brain

Question 9

What inferences can be made from a single dissociation

Answer 9

A single dissociation may suggest that Task A and Task B involve different cognitive processes or neural resources, but other explanations are possible.

Question 10

What is a task-resource artifact in single dissociations?

Answer 10

A task-resource artifact occurs when Task A and Task B rely on the same cognitive or neural resources, but Task B requires more of this resource (i.e., Task B is harder). If brain damage depletes this resource, Task B will be more impaired than Task A.

Question 11

How does transcranial direct current stimulation work

Answer 11

The electrical stimulation makes neurons more likely or less likely to fire

goal is to modulate brain activity

Question 12

What is a task-demand artifact in single dissociations?

Answer 12

A task-demand artifact occurs when a single dissociation arises because the patient performs one task suboptimally, not due to actual cognitive impairment (e.g., misunderstanding instructions or using an unusual strategy).

Question 13

How can task-demand artifacts be minimized?

Answer 13

Task-demand artifacts can be reduced by:

Assessing general intellectual functioning.
Giving clearer instructions or training.
Using ecologically valid tests.
Repeating the test on multiple occasions.

Question 14

What is a split-brain procedure?

Answer 14

A surgical procedure in which the fibers of the corpus callosum are severed, disconnecting the two hemispheres of the brain.

Question 15

What is a stroke (cerebrovascular accident, CVA)?

Answer 15

A disruption in blood supply to the brain, leading to oxygen deprivation and potential brain damage.

Question 16

What is an aneurysm?

Answer 16

An over-elastic region of an artery that is prone to rupture, potentially causing a stroke.

Question 17

What is a double dissociation?

Answer 17

A double dissociation occurs when two patients show complementary deficits:

Patient A is impaired on Task X but not Task Y.
Patient B is impaired on Task Y but not Task X.
This provides strong evidence that different neural/cognitive resources are involved in each task.

Question 18

How does double dissociation help rule out task-resource artifacts?

Answer 18

A single dissociation may occur because one task is harder than another (task-resource artifact). A double dissociation disproves this because each patient is impaired on a different task, meaning task difficulty alone cannot explain the pattern.

Question 19

What is a possible explanation for the co-occurrence of two symptoms in a patient?

Answer 19

The most common explanation is neuroanatomical proximity—if two functions are processed in nearby brain regions, damage to that area is likely to affect both (e.g., face recognition and color perception).

Question 20

Why do some researchers argue that the frequency of a dissociation matters?

Answer 20

if a dissociation occurs rarely, it might be due to random chance rather than reflecting a meaningful distinction (Robertson et al., 1993).

Question 21

Why has the use of double dissociation been criticized?

Answer 21

Some argue that double dissociations imply a modular view of cognition (Fodor, 1983), but this is debated.

Question 22

Can non-modular systems produce double dissociations?

Answer 22

Yes, interactive connectionist models (Plaut, 1995) can also produce double dissociations, as they contain functionally specialized units that process certain types of information more than others.

Question 23

How does brain imaging support functional specialization?

Answer 23

Brain imaging suggests that functional specialization is a natural consequence of the brain’s network architecture, where neurons processing similar types of information connect densely (Bullmore & Sporns, 2009)

Question 24

Dysgraphia

Answer 24

difficulties in spelling and writing

Question 25

Why has the reliance on double dissociations been criticized?

Answer 25

Some argue that double dissociations require the study of "pure" cases (patients with only one deficit), which are rare (Dunn & Kirsner, 2003). However, Shallice (1979) argues that this is unnecessary if the additional deficits (e.g., amnesia in a dysgraphic patient) are unrelated to the cognitive function being studied.

Question 26

What is a syndrome in neuropsychology?

Answer 26

A syndrome is a cluster of different symptoms that are believed to be meaningfully related.

Question 27

Why is double dissociation not the only tool in neuropsychology?

Answer 27

Double dissociation is useful, but additional evidence is needed from: Other relevant tasks (e.g., can dysgraphic patients copy or recognize letters?). Error types, which can reveal underlying cognitive mechanisms. Observations beyond performance level (not just how impaired a patient is, but how they make mistakes).

Question 28

How was the independence of consonants and vowels in dysgraphia first inferred?

Answer 28

It was originally inferred from the types of errors patients made (Caramazza & Miceli, 1990), rather than from double dissociation logic.

Question 29

What are the two broad traditions of patient-based neuropsychology?

Answer 29

1. Classical neuropsychology - Infers the function of brain regions by studying patients with lesions and examining their impaired and spared abilities. 2. Cognitive neuropsychology - Uses patterns of impairment to infer the building blocks of cognition, regardless of their brain location.

Question 30

How has classical neuropsychology benefited from modern technology?

Answer 30

- The development of brain imaging methods has improved lesion localization and quantification. - This provides more accurate lesion-deficit associations and constrains functional imaging interpretations.

Question 31

What study designs are preferred in classical vs. cognitive neuropsychology?

Answer 31

- Classical neuropsychology favors group studies to establish lesion-deficit associations. - Cognitive neuropsychology favors single-case studies to examine how cognitive processes might be subdivided.

Question 32

Why do both classical and cognitive neuropsychology rely on detailed cognitive assessments?

Answer 32

- To determine the specificity of deficits. - To ensure observed impairments are not due to unrelated cognitive dysfunction.

Question 33

Who formalized the logic of using single-case studies in neuropsychology?

Answer 33

Caramazza (1986, 1992) provided one of the first serious attempts to formalize the logic behind single-case studies in neuropsychology.

Question 34

What are Caramazza’s three assumptions in neuropsychology? lesions

Answer 34

1. Fractionation assumption – Brain damage can produce selective cognitive lesions within a cognitive model. 2. Transparency assumption – Brain lesions affect existing cognitive components but do not create an entirely new cognitive system. 3. Universality assumption – All cognitive systems are fundamentally the same across individuals.

Question 35

What does the fractionation assumption state? Caramazza’s lesions

Answer 35

Brain damage can lead to specific cognitive impairments within a cognitive model, rather than causing general dysfunction.

Question 36

What does the universality assumption state? Caramazza’s lesions

Answer 36

The cognitive architecture of all humans is fundamentally the same, allowing single-case studies to inform general cognition theories.

Question 37

What does the transparency assumption state? Caramazza’s lesions

Answer 37

Brain lesions may disrupt cognitive functions but do not create a new cognitive system—the preexisting system remains intact.

Question 38

Did Caramazza believe his assumptions always hold true?

Answer 38

No, he acknowledged that the assumptions may not always be valid, and their accuracy must be determined through empirical research (Shallice, 2015).

Question 39

What criticism did Kosslyn & Van Kleek (1990) make about the fractionation assumption? lesions

Answer 39

Whether selective cognitive impairments occur depends on neural architecture. They are more likely if neurons performing a function are clustered together rather than distributed across the brain

Question 40

Why is the transparency assumption considered problematic?

Answer 40

It assumes that brain damage removes cognitive components but does not create a new cognitive system. However, brain plasticity and recovery after damage challenge this idea.

Question 41

Why does brain plasticity not necessarily violate the transparency assumption

Answer 41

Recovery (e.g., regaining speech after a stroke) may reflect reinstatement of the preexisting system rather than the creation of an entirely new cognitive system

Question 42

How does the transparency assumption relate to location vs. function?

Answer 42

the assumption applies to the cognitive organization of a system, not its location. For example, if the right hemisphere takes over speech after left hemisphere removal, the assumption holds if the function remains the same.

Question 43

When is the transparency assumption more likely to hold?

Answer 43

It is less likely to be violated in: 1. Adults compared to children. 2. Studies conducted soon after injury rather than long-term. 3. Cases where the cognitive profile remains stable over time.

Question 44

What is a key challenge of the universality assumption?

Answer 44

It assumes all cognitive systems are fundamentally the same, but individual differences (e.g., expertise, cognitive efficiency) may affect performance

Question 45

How can individual differences affect lesion studies?

Answer 45

If different individuals rely on different cognitive strategies, an identical lesion might produce different symptoms (e.g., different reading strategies affect reading impairments).

Question 46

What did Caramazza & McCloskey (1988) argue about single-case studies?

Answer 46

They argued that single-case studies are the only acceptable method in cognitive neuropsychology.

Question 47

How did Zurif et al. (1989) respond to Caramazza & McCloskey’s claim?

Answer 47

They defended group studies, arguing that “syndromes are what the world gives us.”

Question 48

What was the main argument against averaging performance in group studies

Answer 48

Patients have different cognitive lesions, so performance differences may be due to lesion variability rather than individual differences in noise, making averaging misleading.

Question 49

How does single-case methodology distinguish between anatomical and cognitive lesions?

Answer 49

- Anatomical lesions refer to structural brain damage. - Cognitive lesions refer to impairments in specific cognitive functions. - Establishing cognitive impairments requires individual cognitive testing, as structural lesions alone cannot predict precise cognitive deficits.

Question 50

When could averaging across patients be legitimate, according to Caramazza?

Answer 50

Only if all patients have identical cognitive lesions. However, this would still be a series of single-case studies, not a traditional group study.

Question 51

What are common criticisms of single-case studies?

Answer 51

- Theories in neuropsychology are built from multiple sources (normal and brain-damaged cases). - Replication within a single case prevents findings from being dismissed as random noise.

Question 52

Why has the use of single-case studies declined in recent years?

Answer 52

- Rise of neuroimaging allows for large-scale group analysis. - Logistical challenges of studying one patient in-depth over months or years. - Concerns over replicability, despite the fact that single-case studies often include internal replication.

Question 53

What is the primary strength of single-case studies in neuropsychology?

Answer 53

Single-case studies are particularly useful for determining the components of cognitive systems, as they allow detailed examination of individual cognitive impairments.

Question 54

How can the term "lesion" be interpreted in neuropsychology?

Answer 54

1. As a disruption to a cognitive component within a theoretical model. 2. As an organic brain lesion (physical brain damage).

Question 55

Do group studies have a role in neuropsychology?

Answer 55

Yes, group studies are valuable and may be better suited for addressing different types of research questions compared to single-case studies

Question 56

What are the two main approaches in neuropsychology?

Answer 56

1. Cognitive neuropsychology – Focuses on understanding how the mind processes information without linking it to specific brain regions. 2. Classical neuropsychology – Focuses on identifying which brain areas are responsible for specific cognitive functions, often by studying patients with brain damage.

Question 57

How does classical neuropsychology determine which brain regions are essential for a task?

Answer 57

It studies groups of patients with similar brain damage to see if a particular brain region is necessary for a given function. This contrasts with brain imaging, which only shows correlations between brain activity and cognitive functions.

Question 58

What are three ways to group patients in neuropsychological research?

Answer 58

1. Grouping by syndrome – Patients are grouped based on a cluster of symptoms (e.g., schizophrenia). 2. Grouping by cognitive symptom – Patients are grouped based on a specific symptom (e.g., auditory hallucinations). 3. Grouping by anatomical lesion – Patients are grouped based on damage to a specific brain region.

Question 59

What is the advantage of grouping patients by cognitive symptom?

Answer 59

It provides a fine-grained analysis of how a specific symptom relates to brain damage, rather than grouping based on broad syndromes.

Question 60

What is voxel-based lesion mapping, and how is it useful?

Answer 60

It is a technique that compares lesion locations across multiple patients using MRI, allowing researchers to find statistical “hot spots” where brain damage is linked to cognitive deficits.

Question 61

Why might grouping by anatomical lesion be misleading?

Answer 61

If a cognitive deficit can result from damage to either region X or region Y, but only region X is studied, researchers might falsely conclude that only region X is critical.

Question 62

When is grouping by lesion site most useful?

Answer 62

When there is a specific hypothesis about what a brain region does, often based on prior functional imaging studies

Question 63

What is Transcranial Magnetic Stimulation (TMS)?

Answer 63

A technique that uses electromagnetic induction to create a temporary "virtual lesion" in the brain, disrupting neural activity.

Question 64

What are the advantages of TMS?

Answer 64

- Allows researchers to infer causality between brain activity and function. - Effects are temporary and reversible. - Can be targeted to specific brain areas.

Question 65

How has TMS been used in language lateralization studies?

Answer 65

By disrupting activity in different hemispheres, TMS helps identify which side of the brain is dominant for language processing.

Question 66

What are the main types of Transcranial Electric Stimulation (TES)?

Answer 66

1. tDCS (Transcranial Direct Current Stimulation) – Applies a weak direct current. 2. tACS (Transcranial Alternating Current Stimulation) – Uses oscillating currents to target brain rhythms. 3. tRNS (Transcranial Random Noise Stimulation) – Applies random electrical noise to enhance brain activity.

Question 67

How do anodal and cathodal tDCS affect brain activity?

Answer 67

- Anodal tDCS increases excitability by enhancing glutamate activity. - Cathodal tDCS decreases excitability by increasing GABA inhibition

Question 68

How does tACS influence lucid dreaming?

Answer 68

tACS at 40 Hz (gamma frequency) applied to the frontal cortex has been shown to induce lucid dreaming by increasing conscious awareness during sleep.

Question 69

What EEG patterns are associated with lucid dreaming?

Answer 69

Increased gamma wave activity in the frontal cortex, which is linked to self-awareness and control.

Question 70

What are the main causes of brain damage?

Answer 70

- Stroke (ischemic or hemorrhagic) - Tumors - Head injuries (TBI, concussion) - Neurodegenerative diseases (Alzheimer’s, Parkinson’s)

Question 71

What is the difference between an ischemic and a hemorrhagic stroke?

Answer 71

- Ischemic stroke – Caused by a blockage in a blood vessel. - Hemorrhagic stroke – Caused by a ruptured blood vessel, leading to bleeding in the brain.

Question 72

What are the main types of neuropsychological tests?

Answer 72

1. Intelligence tests (IQ tests) 2. Memory tests (e.g., digit span, recall tasks) 3. Visuospatial tests (e.g., Rey-Osterrieth Figure Test) 4. Executive function tests (e.g., Wisconsin Card Sorting Task)

Question 73

What is the Pyramids and Palm Trees test used for?

Answer 73

It assesses semantic memory by testing a person's ability to identify conceptual relationships between images.

Question 74

What is an example of a double dissociation in neuropsychology? the classic one

Answer 74

Broca’s aphasia vs. Wernicke’s aphasia: - Broca’s aphasia – Impaired speech production, but comprehension intact. - Wernicke’s aphasia – Fluent but nonsensical speech, with impaired comprehension.

Question 75

Why can’t we always average observations from single-case studies?

Answer 75

Each patient has different lesion locations, meaning averaging could hide important individual differences in brain function.

Question 76

Why is it important to test each patient separately in single-case studies?

Answer 76

It allows researchers to identify specific cognitive deficits without assuming all patients have the same impairments.

Question 77

What are three main methods used to study the lesioned brain?

Answer 77

1. Neuropsychology – Studying patients with brain damage to understand cognition. 2. TMS – Creating temporary "virtual lesions" to test brain function. 3. tDCS/tACS – Using electric currents to modulate brain activity.