Memory and movement disorders Flashcards
3 stages of memory
sensory, working, and long-term
Sensory memory
retention of environmental stimuli one attends to for 25-2000 ms with a large capacity
Working memory
retention of information one selectively attends to for 15-30 s with a limited capacity of 7(+ or - 2) units if repeatedly rehearsed
Long-term memory
information that is encoded and stored for an infinite period of time and unlimited capacity but may decay over time leading to retrieval failures
2 main memory systems
short-term/working and long-term memory
2 main branches of LTM
explicit (declarative) and implicit (non-declarative)
Explicit vs implicit meory
consciously recalling information; demonstrating evidence of information through behavior without describing it
Types of explicit memory
episodic (retrospective, prospective) and semantic
Retrospective episodic memory
retention of specific personal experiences in the past minutes, days, or years from a first-person perspective, which includes time and place, and involves autonoetic consciousness (mental time travel)
Prospective episodic memory
remembering to do something at a particular moment in the future or the timely execution of a previously formed intention
3 behaviors operationally involved in prospective memory
formation of intention, delay (intention leaves focus of attention), task execution
Characteristics of semantic memory
non-contextual knowledge (i.e. facts); no autonoetic consciousness; semanticization; less dependent on medial temporal structures for retrieval; material-specific deficits possible
Semanticization
episodic memories become decontextualized over time
Types of implicit memory
procedural, conditioning, priming
Procedural memory
acquisition of skills/habits from repeated practice that become resistant to decay
Conditioning
reactions resulting from reinforcements or formed associations between stimuli that co-occurs over time
Priming
facilitation of task performance induced by recent exposure to a previous stimulus
Roles of hippocampus vs cortex in memory
more involved in initial acquisition of information; more involved in consolidation
Contributions of the frontal systems of the brain
working memory, organization at encoding, source memory, strategic search at retrieval from LTM
Brain regions involved in semantic vs episodic memory that affect encoding and consolidation
cerebral cortex and limbic structures; prefrontal cortex and limbic system
Brain regions involved in semantic vs episodic memory that affect retrieval
left frontotemporal cortex; right frontotemporal cortex and limbic regions
Diseases associated with damage in the medial temporal cortex
alzheimer’s, mesial temporal lobe epilepsy, anoxia, limbic encephalitis, korsakoff’s disease
Memory problems caused by damage in the medial temporal cortex
encoding and consolidation of episodic memory
Diseases associated with damage in the frontal-subcortical system
TBI, multiple sclerosis, HIV/AIDS, vascular MCI, parkinson’s, huntington’s
Memory problems caused by damage in the frontal-subcortical system
retrieval and working memory
Retrograde amnesia
inability to consciously reactivate information that was consolidated a long time ago; follows a temporal gradient
Temporal gradient in retrograde amnesia
recently formed memories are unaffected while older memories (before the onset of amnesia) are more sensitive to disruption
Diseases that co-occur with retrograde amnesia
TBI, korsakoff’s, advanced dementia, ECT, and usually anterograde amnesia (except for psychogenic amnesia)
Confabulation
presenting distorted/false information due to unintentional episodic misremembering
Brain regions damaged in confabulation
medial temporal and frontal cortex
Diseases involving confabulation
ACommA, korsakoff’s
2 pyramidal tracts
corticospinal tract and corticobulbar tract
Pathway of corticospinal tract
primary motor cortex > corona radiata > medulla > synapses at spinal cord into lateral and anterior corticospinal tract > lower motor neuron for movement of limbs and trunk
Representation of lower vs upper extremities in the motor cortex
lower extremities (e.g. foot, toes, genitals) are more medial while upper extremities (e.g. head, neck, arm, shoulder) are more lateral
Pathway of corticobulbar tract
primary motor cortex > corona radiata > medulla > synapses on lower motor neurons of cranial nerves for movement of muscles in face, head, and neck
Type of deficits caused by pyramidal tract lesions
contralateral motor deficits
3 types of corticospinal tract lesions
weakness, increased tone (spasticity or stiff muscles), increased reflexes in affected region
Upper motor neuron lesion
weakness, increased reflexes and tone but no atrophy and fasciculations (muscle twitching)
Lower motor neuron lesion
weakness, atrophy, fasciculations, decreased reflexes and tone
4 signs of a stroke
FACE (face dropping, ability to raise arms, slurred speech, time to call 911 asap)
-paresis vs -plegia
weakness (partial paralysis); complete paralysis
Palsy
weakness or complete paralysis due to lower motor neuron lesion
Results of basal ganglia damage
contralateral movement disorder, weakness and involuntary movements, cognitive and behavioral changes
2 main categories of basal ganglia disorders
hypokinetic (less than normal movement) and hyperkinetic
Deficit caused by lesions to lateral cerebellum
limb incoordination
Deficit caused by lesions to medial cerebellum
trunk and posture problems
Deficits caused by general lesions to the cerebellum
ipsilateral deficits (due to double crossing) like ataxic gait, intention tremor, nystagmus, scanning speech
Nystagmus
eyes make uncontrolled repetitive movements
Scanning speech
abnormal pattern of speech wherein there’s a pause after every syllable
2 disorders involving increased muscle tone
spasticity and rigidity
Spasticity
velocity-dependent resistance to passive muscle stretch
Rigidity
resistance to passive movement that doesn’t vary with velocity or force
5 hyperkinetic movement disorders
tremor, tics, myoclonus, chorea, athetosis
Tremor
rhythmic oscillations caused by intermittent muscle contractions
Tics
paroxysmal or sudden stereotyped muscle contractions (temporarily suppressible)
Myoclonus
shock-like arrhythmic twitches
Chorea
dance-like unpatterned movements; seen in parkinson’s and affects the putamen
Athetosis
continuous writhing movements to maintain posture; seen in parkinson’s and affects the putamen
Tremor
rhythmic muscle contractions
3 types of tremors
essential, resting, action
Essential vs resting vs action tremors
constant, bilateral, symmetric; happens when skeletal muscle is at rest (e.g. parkinson’s); happens during voluntary movement
3 types of gait disorders
spastic/hemiplegic, ataxic, parkinsonian
Spastic/hemiplegic gait
stiff-legged and decreased arm swings on same side; seen in MCA stroke and cerebral palsy
Ataxic gait
wide-based, staggering, unsteady; seen in cerebellar stroke/tumor, alcohol intoxication
Parkinsonian gait
shuffling, narrow-based; seen in parkinson’s, progressive supranuclear palsy, neuroleptic drugs
Apraxia
inability to perform previously learned, sequential motor movements (e.g. using familiar objects correctly or carrying out familiar multi-step actions); not explained by weakness or motor incoordination
Treatments for upper limb weakness
constraint-induced movement therapy and mirror therapy
Treatments for fine motor incoordination
functional dexterity tasks
Treatments for spasticity
splints and botulinum toxin type A (botox)
Treatment for hyperkinetic movement disorders
deep brain stimulation
