Final

Psychology 310 with Mayhew at Rutgers University - New Brunswick/Piscataway

About this deck

By: max bobinski
Textbook:

Phantoms in the Brain: Probing the Mysteries of the Human Mind

Principles of Neuropsychology
Created: 2011-12-20
Size: 83 flashcards
Views: 284

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Cerebral Asymmetry

In males - asymmetry in the volumes of the hemispheres
In females - Volume symmetry in hemispheres

Lateralization of function

Despite similarities, each hemisphere is managed differently

Sylvian fissure in the right hemisphere

fissure is steeper
the temporal lobe is therefore bigger, the parietal is smaller

Sylvian fissure in the left hemisphere

Fissure is longer

Asymmetries favoring the LEFT hemisphere

- longer sylvian fissure
- larger cingulate gyrus (double sized)
- larger platnum temporale (wernekie's area)
- more gray matter
- larger inferior posterior parietal lobe

Asymmetries favoring the RIGHT hemisphere

- has 2 Hechl's gyri (primary auditory cortex)
- more white matter
- wider frontal lobe
- larger temporal lobe

Wada test

- anesthetize one hemisphere to see what the other side does (drugs are put in the corresponding carotid artery)
Results: shows 98% of right-handers and 70% of lefties have language processing in the left hemisphere

Corpus Callosum

- dense, fat-like axons that connect the hemispheres
- shares information between the hemispheres
- we did not know the function of the CC until the 20th century, during animal testing

Commisurotomy

- cutting the corpus callosum
- done to limit convulsions in patients

Results of commisurotomy (what does each hemisphere do?)

Left - is stronger in tasks and responding requiring language (can TELL what is seen)
Right - cannot respond linguistically, but can understand language (can SHOW what is seen)

Sidedness in Tachistoscope (sight test)

Right field (left hemisphere) - words
Left field (right hemisphere) - pitcures

Advantages (specialization) in LEFT hemisphere

Vision - words and letters
Audition - linguistic stimuli
Language - speech/reading/writing/math
Movement - complex and cognitively driven movement

Advantages (specialization) in RIGHT hemisphere

Vision - faces, geometric patterns, emotional expression
Audition - nonlanguage sounds, music
Memory - nonverbal, perceptual
Language - emotional content, tone
Movement - spatial patterns
Touch - tactile patterns (braille)
Spatial ability - mental rotation, geometry, shapes, direction

Handedness (names)

Dextral (right handed)
Sinestral (left handed)
- left hemisphere is dominant in almost everyone

Which gender uses both hemispheres for speech?

Females, men do as well, just less often

Sex differences in abilities

Males - target throwing, mental rotation, spatial navigation, geographical knowledge, reasoning
Females - fine motor skill, spatial memory, computation, sensitivity to sensory stimuli, faster perceptual speed, sensitivity to expression, visual memory, fluency/word memory

Plasticity

- brain changes during a lifetime
- shown in learning and remembering

Changes in cortical maps (plasticity)

- an increase in gray matter with learning
- areas "taking over" others. ex) Ramachandran's '98 study, a man who lost his hand had his facial area take over the hand area

Microscopic change in Plasticity

- synaptic organization
- molecular structure
- mitotic activity (cells proliferating)
- drugs induce structure change as well (ex: stimulants)

Diaschisis

- a passive process in uncovering working neural systems after temporary neural disruption in areas far away from the lesion site (but are neurally connected to it)

Recovery path for Hemiplegia (loss of movement after stroke)

- is exactly the same as the development of reaching and grasping in infants

When is recovery for aphasia quickest?

- when it was brought on by TBI, recovery is much slower after a stroke

Study in open head injury in soldiers and recovery

After 20 years, 50% had not made any recovery whatsoever

Hemispherectomy

- an entire hemisphere is removed, but deep brain structures are left intact (thalamus, stem, basal ganglia)
- done to treat epilepsy when its localized to a large area in one hemisphere (very severe)
- main recovery variable is age

Constraint-induced movement therapy

- improves upper extremity function after stroke
- forces patient to use the affected limb by immobilizing the other one (with some sort of constraint)
- done in stroke victims and kids with cerebral palsy

Variables affecting recovery from injury/stroke

- lesion size
- age (the younger the better)
- handedness
- sex (women do better - localization differences)
- intelligence (the smarter the better)
- personality
- if the primary somatosensory cortex survives stroke, some function improvement is likely
- reorganization is bilateral

Experimental therapies (stroke)

- pharmacological
- brain stimulation
- brain -tissue transplant

Explicit long-term memory

- Semantic Memory (meaning and experiences)
- Episodic Memory

Implicit long-term memory

- procedural memory
- skills
- priming
- conditioning

Long Term Memory

- explicit
- implicit
- emotional

H.M.

- man with epilepsy in youth
- bilateral removal of medial temporal structures to stop seizures
- could no longer form long-term memories
- dies 55 years post-operation
- had global anterograde amnesia

Anterograde Amnesia

- difficulties learning new things and creating new memories

Retrograde Amnesia

- difficulty retrieving old memories

Systems involved in Episodic Memory

- medial-temporal-lobe-ventral-frontal-lobe
- Hippocampus, Perirhinal & Parahippocampal corticies
- Frontal cortex
semantic memory depends less on this system

Hippocampal Complex

- Ammon's horn & Dentate gyrus (temporal lobe)
Connections:
- Preforant pathway (from entorhinal cortex)
- Fimbria-Fornix

Consolidation

The process by which movement-to-movement changes in brain activity are translated into permanent structural changes in the brain
- the medial temporal lobes require consolidation
- amnesia is a consolidation problem in the hippocampus

Memory Impairments from lesions or removal (near hippocampus)

- Temporal neocortex (adjacent to medial) Right - impaired face recognition, spatial-position and language learning. Left - impaired word-list learning, non-spatial associations
- Parietal and occipital - color amnesia, topographic amnesia, object amnesia

Frontal Cortex and memory

Left prefrontal cortex - encoding > retrieval of semantic/episodic information
Right prefrontal cortex - retrieval of semantic/episodic memory > encoding

Korsakoff's Syndrome

- caused by long term alcoholism, which brings about a deficiency in thiamine (B1)
- massive doses of B1 can stop symptoms, but not reverse them
Symptoms:
both anterograde and retrograde amnesia, confabulations, lack of insight, apathy

Procedural (implicit) memory

- memory, priming, conditioning (associative learning)
- was preserved in H.M.
- Basal ganglia, motor cortex, cerebellum
- emotional memory can be both implicit and explicit, amygdala important

Short-term memory deficits (rare)

- KF left posterior temporal lesion
- inability to repeat verbal stimuli, but LTM left intact

Working Memory

- articulatory loop (left hemisphere) - sound phenomenon
- visuospatial sketchpad (right hemisphere) - what we see
- episodic buffer - dorsolateral PFC keeps things 'online'; links LTM and meaning

Wernicke-Geschwind model (old language model)

- based on lesion studies
- areas used: broca's, wernicke's, face area, 17-19, 39, 41, 42
- comprehension, speech, and reading were analyzed
- new imaging techniques allowed for a diversion from this model

Activation in brain during listening (fMRI)

- comprehension goes beyond just wernickie's area
- different areas in temporal lobe activate when hearing noun types (people, animals, tools)
- many areas activate (broca/werneckie, parietal/temporal lobe) when listening to and repeating words, or when generating uses for words
- language activates areas normally used in primary functioning
- cortical representation of speech movements is not all broca's areas does - also holds meanings

Aphasia

disorder of language in speech, or writing/reading produced by brain injury

Where do most patients with language disorders have damage?

MCA

Language defecits post-stroke...

can recover over time

Nonfluent Aphasias

Broca's
Transcortical Motor
Global

Broca's Aphasia (nonfluent)

expressive aphasia
- main symptom: can understand speech, but has problems producing speech (especially repetition)
- trouble in understanding prepositions and conjunctions
- some have trouble with articulation, repetition, speechlessness and phonetic disentigration

Moderate Broca's Aphasia

Slight articulation issues (obvious to an observer), paraphrasia (unintended words), anomia (cannot pick the right word), agrammatism, impaired prosody (rhythm)

Transcortical Motor Aphasia (nonfluent)

- good repetition, but poor spontaneous production
- small lesion, superior to broca's area

Global Aphasia (nonfluent)

- the worst kind
- labored speech, poor comprehension
- massive lesions
- can't speak or comprehend

Apraxia

- damage to cerebellum
- articulatory inconsistencies
- groping oral movement
- errors in word and phrase length

Fluent Aphasias

- impairment in the comprehension of language
- can be fluent in speech/articulation
- problems in understanding, repeating and retrieval
types: wernicke's, transcortical sensory, conduction, anomic

Wernicke's Aphasia (fluent)

- fluent speech without articulation issues
- impaired language comprehension (spoken/written words, nouns/verbs, bad repetition)
- speech has little meaning (severe = word salad)
- neologism - every word seems new
- confusion in phonetic characteristics
- agraphia (can't write)
- anomia (can't retrieve object names) but recognition is ok

Transcortical Sensory Aphasia (fluent)

- normal naming/repetition
- impaired comprehension and speech production

Conduction Aphasia (fluent)

- normal speech production, naming and understanding
- impaired repetition of language

Anomic/amnesic Aphasia (fluent)

- normal comprehension, production, repetition
- impaired in naming objects
- shows anomia and paraphrasia (using the wrong word)

Pure Aphasia

Alexia - an acquired inability to read
Agraphia - inability to write
Word deafness - cannot hear or repeat words

Subcortical structures and damage (in aphasias)

Basal Ganglia (speech articulation)
Thalamus (activates the cortex, influencing language; damage here leads to speech/language disorders - a drop in verbal IQ, slurring, hesitation in speech, reduced vocal volume, increase in verbal response latency)

Acquired Dyslexia (alexia)

- reading impairment after brain damage
Phonological dyslexia - inability to read nonwords, can read "real" words well, damage to phonological route
Surface dyslexia - can only read by sounding words out, troubles with irregular words
Deep dyslexia - semantic errors, impaired writing and ST-verbal memory, damage to both reading systems

Developmental Dyslexia

- failure to learn to read during development
Surface dyslexia - impaired whole word reading
Deep dyslexia - impaired ability to sound out words

Neglect Dyslexia

- misreading the first or second half of a word

Attentional Dyslexia

- can't name letters well when more than one is present
- difficulty reading when more than one word is present

Dual route model of reading

1) Semantically-based route - visual words to semantics (meaning) and whole word recognition
2) Phonologically-based route - uses spelling-phonological patterns to semantics

Magno-parvocellular view of developmental dyslexia

- dyslexia is the result of a deficit in the magocellular system (in the visual pathway); the parovecullar system is suppressed by the magnocellular system during saccadic eye movements.
- lack of phonological awareness: phonological comprehension is the first step in language learning

Developmental Delays

- failure to meet age-appropriate expectation: based on typical development
early infancy: tense or floppy (interference in muscle development) and feeding problems
6-18 months: serious motor delay
18+ months: language delay and strange behavior
Bayley scales measure development

Defining Mental Retardation

1) significantly subaverage intellect (2 standard deviations)
2) adaptive impairments (communication, self-care, home-living, social skills, academic skills, safety)
3) onset before age 18

Down's syndrome

- incidence 92/1,000 (decreasing)
- trisomy 21
- medical complications (heart disease, thyroid disorder, gastrointestinal issues, epilepsy)
- poor STM, but good visual STM
- motor impairments, language development impairments
- average lifespan: 40-50 years

Fragile X syndrome

- fragile site on x chromosome
- females show less symptoms (have 2 x chromosomes)
- similar to downs (medical/cognitive problems)
- 1/4,000 males, 1/6,000 females

Fetal Alcohol Spectrum Disorder

- growth retardation
- facial abnormalities
- brain structure abnormalities
- neurological deficits
- developmental disabilities

Pervasive Developmental Disorder Spectrum

- autism (13/10,000 - communication issues, repetitive behaviors)
- aspergers (social problems)
- childhood disintegrative disorder (rare - deterioration at age 2)
- retts disorder (only females, at age 5 autism sets in)
- PDD-NOS (not otherwise specified)

Symptoms in PDD spectrum

1) impairments in social abilities (joint attention - indicating a stimulus to someone else)
2) language expression/comprehension impairments
3) preoccupations

Neural basis of autistic symptoms

social - less STS/FFA activation, impaired emotion perception, mirror neuron area thin, different looking patterns (when viewing faces)
language - no differential activation of speech sounds vs non-speech sounds
preoccupations - increased activity in caudate nucleus

Why do people age differently?

genetics, stress, exercise, crystallized vs fluid intelligence (cognitive reserve)

Aging problems/changes (for everyone)

- decrease in processing speed
- memory/new learning problems
- abstract/problem solving problems
- atrophy (shrinks)
- decrease in weight/volume
- frontal cortex - most affected
- less gray and white matter

Mild Cognitive Impairment (MCI)

- transition between aging and dementia
- areas of decline: attention, white matter, language, verbal/nonverbal memory

Dementia

1) loss of cognitive/intellectual function
2) involves multiple areas of impaired cognitive functioning
classifications
- cortical vs subcortical
- static vs progressive
- reversible vs irreversible
- degenerative vs nondegenerative

Alzheimer's Disease

- genetic, cause unknown
- neurodegenerative, progressive, cortical, irreversible
- definite diagnosis only after autopsy
- 50% of dementia cases
- all treatment is experimental

Histological Markers in Alzheimers

Amyloid plaque
Neurofibrillary tangles

Regions affected in Alzheimers

- hippocampus
- cortical atrophy

Symptoms in Alzheimers

- learning problems, lowered retention
- lose previously well known semantic knowledge
- lose STM
- fluent anomic aphasia
- visiospatial impairments
- attention/executive functioning/general intellect problems