Chapter 5

Question 1

Mind and the lesioned brain: classical cases

Answer 1

Tan = language
Phineas Gage = personality
DF = object recognition
HM = memory

Question 2

Reverse engineering

Answer 2

Infer the function of a region (or cognitive mechanism) by removing it and measuring the effects on the rest of the system (e.g. if damage to a region disrupts reading, but not speaking or seeing, than one might conclude that the region is specialized for some aspect of processing text).

Question 3

How does disruption of the brain happen?

Answer 3

(1) Natural damage (stroke, trauma), (2) elicited damage (animal models) or (3) harmless temporary changes induced electro-mechanically (TMS).

Question 4

Neurosurgery

Answer 4

Brain is damaged deliberately.

Question 5

Cerebrovascular accident (CVA)

Answer 5

Accident of the arteries (vascular) of the brain (cerebro). There are two types: (1) Ischemic infarction (80%) = herseninfarct/beroerte, (2) Hemorrhage or bleeding (20%) = hersenbloeding.

Question 6

Traumatic brain injury

Answer 6

Various mechanical forces can result in: (1) Open traumatic brain injury (more localized), (2) closed traumatic brain injury (more widespread effects).

Question 7

Single dissociation

Answer 7

A patient is impaired on task A but (relatively) spaired on task B; classical versus strong dissociation.

Question 8

What inferences can be drawn from single dissociation?

Answer 8

(1) Task A and B rely on different cognitive processes, (2) task-demand artifact (supoptimal performance; misunderstanding), (3) task-resource artifact (same resources, but more needed for task A).

Question 9

Double dissociation

Answer 9

Normally derived from 2 or more single cases with complementary profiles of strengths and weaknesses; used to infer that two tasks/stimuli use separate neural/cognitive resources.

Question 10

Intracranial tumors

Answer 10

Mass of new tissue that persists and grows independently; classification: (1) benign versus malignant, (2) encapsulated versus infiltrating, (3) primary versus secondary, (4) cell types (meninges versus glia).

Question 11

Viral infections

Answer 11

Invasion of the body by disease-producing microorganisms and subsequent tissue reactions.

Question 12

How do infections kill neural cells?

Answer 12

(1) They interfere with blood supply, (2) they disturb glucose of oxygen metabolism, (3) they alter cell membranes, (4) they cause edema (5) they form pus.

Question 13

Associations

Answer 13

Patient is impaired on task A and task B. Perhaps functions are close together in the brain?

Question 14

Syndromes

Answer 14

a cluster of different symptoms that are believed to be related in some meaningful way (e.g. Gerstmann syndrome).

Question 15

Two traditions of human neuropsychology

Answer 15

(1) Cognitive neuropsychological approach: can a particular function be spared/impaired relative to other cognitive functions; adresses questions of what the building block of cognition are (irrespectable of where they are); tends to use single case methodology, (2) Classical neuropsychology approach: What functions are disrupted by damage to region X; adresses questions of functional specialization, converging evidence to functional imaging; tends to use groups study methods.

Question 16

Assumptions underlying single case studies

Answer 16

(1) Fractation assumption: damage to the brain can selectively impair a cognitive function, (2) transparency assumption: other cognitive functions at normal pre-injury levels of efficiency, (3) universality assumption: all individuals share the same cognitive systems.

Question 17

Group studies and lesion-deficit associations

Answer 17

(1) Group by syndrome = useful for investigating neural correlates of a disease pathology (e.g. Alzheimer’s) but not for dissecting cognitive theory, (2) group by behavioral symptom = can potentially identify multiple regions that are implicated in a behavior, (3) group by lesion location = useful for testing predictions derived from functional imaging.

Question 18

Issues related to patient grouping

Answer 18

(1) Some forms of brain damage (e.g. tumors, swelling/edema) make it hard to localize the lesion, (2) diaschisis: brain damage can induce functional lesions at a distance (e.g. when regions function as a network), (3) danger in concluding that a function is localized in a region, or the purpose of that region is to support that function (neophrenology), (4) one needs to consider whether the region performs other functions and if other regions support this function.

Question 19

Advantage single case studies

Answer 19

Can be important to determine what the components of cognitive systems are.

Question 20

Advantage group studies

Answer 20

Can be important for establishing whether a given region is critical for performing a given task.

Question 21

TMS

Answer 21

A coil contains a wire carrying an electrical current, a rapid change in the current creates a magnetic field, the magnetic field induces a current in the nearby neurons (causing them to fire, i.e. generate action potentials, this disrupts cognitive function they may be doing at a certain point in time.

Question 22

Advantage of TMS

Answer 22

No reorganization or compensation, can be used to determine timing of cognition, lesion is focal, lesion can be moved within the same participant, can study functional integration.

Question 23

Advantage of natural damage

Answer 23

Subcortical lesions can be studied, lesions can be accurately localized with MRI, changes in behavior/ cognition are more apparent, clinical relevance is obvious.

Question 24

Brain stimulation to enhance brain function

Answer 24

Therapeutic effects of TMS and tES when repeated a lot, several promising areas of investigation: mood disorders that do not react to other treatments, obsessive compulsive disorder, revalidation after stroke.

Question 25

NIBS

Answer 25

A name for a variety of methods that stimulate the brain noninvasively including by magnetic, electrical and ultrasound methods.

Question 26

tES

Answer 26

Noninvasive stimulation of the brain caused by passing weak electrical current through it, either direct currents (tDCS) or alternating currents (tACS).

Question 27

Split-brain

Answer 27

A surgical procedure in which fibers of the corpus callosum are severed.

Question 28

Aneurysm

Answer 28

Over-elastic region of an artery that is prone to rupture.

Question 29

Dysgraphia

Answer 29

Difficulties in spelling and writing.

Question 30

Edema

Answer 30

A swelling of the brain following injury.

Question 31

Diaschisis

Answer 31

A discrete brain lesion can disrupt the functioning of distant brain regions that are structurally intact.

Question 32

Behavioral neuroscience

Answer 32

Cognitive neuroscience in non-human animals.

Question 33

tDCS

Answer 33

Noninvasive stimulation of the brain caused by passing a weak electrical current through it.

Question 34

tACS

Answer 34

Noninvasive stimulation of the brain caused by passing a weak alternating electrical current through it; the frequency of the alternations can interact with the brain’s own rhythmical activity.

Question 35

tRNS

Answer 35

Noninvasive stimulation of the brain caused by passing a weak electrical current through it, which fluctuates in direction and amplitude.