Review Flashcards on Hemispheric Lateralization and Neurological Impairments

Flashcards for reviewing key vocabulary and concepts related to hemispheric lateralization, aphasia, agnosia, apraxia, neglect, executive functions, amnesia and navigational impairments based on lecture notes.

Hemispheric Lateralization

The doctrine that the two hemispheres are specialized for different tasks and/or modes of processing.

Marc Dax (1836)

Identified that language problems are related to disease of the left hemisphere.

Franz Joseph Gall (1790s)

Founder of phrenology; believed faculties were localized in the brain, and abilities could be determined by examining bumps on the skull.

Paul Broca (1861)

Observed that difficulties in speech production resulted from lesions to the posterior frontal lobe (foot of the third convolution).

Carl Wernicke (1874)

Found that lesions to the posterior superior temporal gyrus (on the left) result in speech comprehension deficits.

Broca's Area

Area of the brain associated with speech production.

Wernicke's Area

Area of the brain associated with speech comprehension.

Sylvian Fissure

Longer in the left hemisphere and its slope is gentler; it relates to the anatomical differences between the hemispheres.

Planum Temporale

Larger on the left side of the brain; it's size may be related to language dominance, since it's not equally present in left-handers.

Split-Brain Patients

Patients who have undergone a commisurotomy (surgery severing the main tracts of fibers connecting the two hemispheres).

Corpus Callosum

The main tract of fibers connecting the two hemispheres

Anterior Commissure

Connects the two hemispheres

Tachistoscopic Presentation

Presenting visual input very briefly (e.g., < 100 ms) or on the far periphery to selectively direct input to one hemisphere.

Dichotic Listening

A method to study auditory lateralization by presenting different inputs simultaneously to both ears and considering which ear is attended to.

Aphasia

Acquired disorders of language resulting from insult to the central nervous system.

Global Aphasia

A severe form of aphasia where the patient has difficulty with both speech production and comprehension.

Conduction Aphasia

A type of aphasia resulting from disruption of the connection between motor and sensory areas, leading to problems in repetition tasks.

Motor (Broca’s) Aphasia

A deficit of language production, characterized by slow, effortful speech, mainly in content words (telegraphic quality).

Sensory (Wernicke’s) Aphasia

Poor comprehension, fluent speech but with phonological and verbal paraphasias.

Anomia

Problems in finding the right word for a concept.

Semantic Impairments

Difficulties and semantic errors across input and output tasks; problems categorizing pictures or words in semantic categories.

Pure Word Deafness (Verbal Agnosia)

A difficulty in computing a phonological representation; patients cannot understand spoken language but are not deaf.

Lexical/Semantic Word Deafness

Impairment in addressing the lexicon after a phonological representation has been properly computed.

Apraxia of Speech

Problem in planning the articulatory realization of words, with distorted sound production.

Dysarthria

Speech disorder due to motor command/execution deficits, often from non-cortical lesions, with consistent errors.

Agrammatic Comprehension

Difficulty understanding sentences when comprehension requires processing grammatical information.

Dysgraphia

Impairments in spelling or writing.

Alexia

The inability to read.

Surface Dysgraphia

Problem with the orthographic lexicon; good spelling of regular words and non-words but poor spelling of irregular words.

Phonological Dysgraphia

Problem with phoneme-grapheme conversion; good spelling of words but poor spelling of non-words.

Deep Dysgraphia

Spelling occurs through the lexical route, but access from the semantic system is reduced, leading to semantic errors.

Allographic Dysgraphia

Mixing fonts (capital and lower case) with better oral than written spelling.

Dyslexia

Difficulties with reading.

Agnosia

Difficulties recognizing objects.

Optic Nerve Damage

Leads to blindness of one eye only (total or partial) which is not a result of cortical lesion.

Optic Chiasm Damage

Leads to blindness in the temporal (lateral) areas of both eyes.

Occipital Lobe Damage to V1

Extensive lesions produce loss of half of the visual field (hemianopia), partial lesions produce a deficit to only a quadrant of the visual field (quadrantopia), and small lesions produce small blind spots (scotomas), there can be spared macular region of the visual field.

Apperceptive Agnosia

Problems in deriving a complete representation from a visual input, difficulty copying or drawing objects.

Associative Agnosia

The problem is in linking an intact visual percept to the corresponding concept.

Simultagnosia

Attention is may be focused on individual details and the whole object is missed

Optic Ataxia

A deficit in reaching/grasping under visual guidance, difficulty forming the appropriate hand posture for different objects.

Ideomotor Apraxia

Problem with spatio-temporal realization of gestures

Ideational/Conceptual Apraxia

Conceptual problems with functional knowledge about objects

Parietal Lobe

Located in the cerebral cortex, involved in many functions, including processing somatosensory information like touch, temperature, and pain.

Neglect

Cognitive inability to respond to objects and people located on the side contralateral to a cerebral lesion.

Anosognosia

A symptom often associated with neglect, denying ownerships of limbs on the left side of the body. The patient fails to recognize that the left arm/leg belong to him.

Executive Functions

Functions involved in setting up and ‘executing’ goals in the context of complex and novel tasks.

Dysexecutive syndrome

Difficulties with abstract thinking, problem solving and control

Dorsolateral Prefrontal Cortex

EF proper - planning, reasoning, problem solving decomposable in more individual skills involving inhibition, shifting, working memory.

Diencephalon

Made up of the thalamus allowing crude perceptions (other parts are the hypothalamus, epithalamus and subthalamus)

Retrograde Amnesia

Deficit of retrieval, difficulty recalling past events.

Anterograde Amnesia

Deficit of encoding/storage, difficulty forming new memories.

Hippocampus

Associated with consolidation and retrieval of memories..

Declarative Memory

Explicit and can be learned in one go, complex learned explicitly

Procedural Memory

Can do skills

Episodic Memory

About personally experienced events and their temporal relations.

Topographical Disorientation

Navigation Disorders

Egocentric navigation

landmark/route strategy, related to landmark knowledge -served by an ensemble of areas -hippocampal

Allocentric navigation

survey strategy/cognitive map -serves an ensemble of areas -hippocampal

Cognitive Map

Ability Individuals to use directional information based on egocentric representation as well as landmarks