Theories in Neuropsychology

Question 1

Two dominant paradigms concerning cerebral functional organization in neuropsychology

Answer 1

1. Domain specific (“localization”) theory
2. Domain general (“Generalist”) theory

Question 2

Cerebral Location Theory

Answer 2

Domain-specificity

Dominant paradigm.

Theory states:
1. Brain has modular organization.
2. Each module is specialized processor devoted to one task/function (e.g., expressive speech, facial recognition).
3. Each specialized processor is reliably associated with specific zones in the brain (left inferior frontal gyrus –> expressive speech; inferior temporal lobes + fusiform gyrus –> facial recognition).

Question 3

Domain-General Theory

Answer 3

Mental function is NOT reducible to specific anatomic locations in the brain, it works in a wholistic sense.

Theory states:
1. The brain has only one or a few fundamental properties, such as general learning and reasoning capacity, a position also favored by behaviorists and anthropologists.
2. Any mental act or function requires the entire brain working in concert.
3. Long-term memory is distributed around the brain.
4. Symptoms are in part the expression of the undamaged part of the brain.
5. Only motor and sensory functions are localized, not higher cognitive functions. Brain tissue has equipotentiality: any brain area can do what any other brain area can do for perception; only sensory and motor function are specialized.
6. The observed variety of organic syndromes is explained by either lesion size, lesion “intensity,” or the combination of the fundamental cognitive deficit (whatever it is) with a specific motor-sensory impairment.

Question 4

Franz Gall

Answer 4

Proposed personality traits were localized and predictable by studying variations in the skull contour.

Phrenology.

Two important breakthroughs:
1. materialist view of the brain as subject to scientific scrutiny
2. mental modularity/localization (of personality traits or “faculties,” rather than cognitive functions, in this view)

Question 5

Paul Pierre Broca

Answer 5

Cerebral dominance idea:
1. acquired language loss was reliably associated with left-brain strokes in most patients
2. loss of expressive speech and syntactic sentence structure was associated with left frontal strokes.

Question 6

Carl Wernicke

Answer 6

Further correlated aphasia types. Observed:
1. auditory comprehension (receptive language) was impaired in the left hemisphere posterior lesions.
2. disconnection explained why some left subcortical (e.g., white matter) lesions affected language repetition but not comprehension (e.g., conduction aphasia due to damage to the arcuate fasciculus).

Question 7

Joseph Dejerine

Answer 7

Described two forms of reading loss or “alexia” associated with either:
1. direct destruction of left angular and supramarginal gyrus of the left brain
2. disconnection of visual input to an intact memory center.

Question 8

William James

Answer 8

Proposed the brain evolved to contain dozens or hundreds of instincts.

Question 9

Hugo Liepmann

Answer 9

Showed the left parietal lesions affected skilled movements in both hands, even when language was intact (ideomotor praxis).

Question 10

Alexander Luria

Answer 10

Sytematized the modular geography of the entire brain based on inferences from clinical cases consisting mostly of Russian soldiers with brain injuries.

Question 11

Who are the key figures in the Generalist view?

Answer 11

Wolfgang Kohler
John B. Watson
B.F. Skinner
John Hughlings Jackson
Lev Vygotsky
Karl Lashley
Kurt Goldstein

Question 12

Who was Hans Lukas Teuber?

Answer 12

Coined “double dissociation”.

A double dissociation occurs when a lesion in brain zone A impairs verbal memory but not visual memory, but a lesion in zone B weakens or impairs visual memory but not verbal learning.

Question 13

Who was Norman Geschwind?

Answer 13

Disconnection syndromes.

Proved that small lesions that interrupt subcortical pathways to specific brain zones still result in specific impairment (e.g., Alexia without agraphia).

Question 14

Cerebral Laterality

Answer 14

Middle theory/hybrid for domain specific and general.

Proposes two domain-general processors in which the two halves of our brain are organized differently and control qualitatively different (but still broad) classes of behavior.

Laterality theory goes under other names, including “cerebral asymmetry” and “hemispheric specialization.”

Question 15

What’s the difference between Automaticity vs. Effortful processing?

Answer 15

1. Automaticity Refers to behavioral routines that are carried out quickly, effortlessly, accurately, and with little forethought. A popular synonym from clinical jargon is “overlearned.” Examples include basic mental addition or reciting math facts, digits forward, speaking and formulating sentences, recognizing written words, greetings and helping responses in social settings, and motor skills such as riding a bicycle. Individuals with normal reading skills (those without a reading disorder) for example, are said to read automatically, effortlessly. Poor readers typically do not read effortlessly.
2. Effortful Processing Refers to mental operations carried out with effort, planning, and careful attention to proximate conditions. Synonyms are “effortful” and “online.” Examples include striking out all the letter A’s preceded by the letter X in a novel cancellation task, reciting digits backward, driving to an unfamiliar location, remembering what you did last Tuesday, and learning a new work skill.

Question 16

Brain Reserve Hypothesis

Answer 16

aka Cerebral Reserve

Refers to a brain’s ability to absorb insult and potentially recover.

Described as a “passive threshold model” because it hinges primarily on the brain’s physical health prior to insult or disease onset.

The BRH states that a critical threshold of brain cell loss must be crossed before a deficit achieves clinical expression in symptoms or test score abnormalities. Those with “brain matter to spare” (more brain cells or denser synaptic networks) are less likely to show observed deficits, despite documented brain disease.

Question 17

Cognitive Reserve Hypothesis

Answer 17

Education and enriched experience can increase cerebral reserve and are relatively protective against the expression of symptoms following brain disease or injury.

Higher cognitive reserve does not prevent dementia or impairments following traumatic brain injury (TBI) or other neurological conditions, but it can modify the functional and clinical expression of such conditions.

Is an “efficiency model” because it refers to the mind’s resistance to brain damage due to the presence of more efficient synaptic networks or preexisting cognitive abilities.