Influence of Sleep and Exercise on Memory and Learning Flashcards
2 stages of sleep
non-REM
REM
non-REM sleep
-stages
stage 1 -transition from wakefulness to sleep stage 2 -conscious awareness fades completely flow wave sleep (stages 3-4) -slow delta wave activity -deep sleep
REM sleep characteristic
paradoxical sleep
-EEG pattern similar to normal wakefulness pattern
effects of sleep on consolidation
consolidation is enhanced by sleep
- skill memory more resistant to interference after sleep
- -learning of fine motor tasks greater after 90 minute sleep immediately following practice
- neural reactivation observed during SWS and non-REM
which subcategory of consolidation is dependent on sleep?
enhancement
sleep-dependent memory mechanisms
synaptic homeostasis hypothesis (SHY)
- changes in synaptic strength are primary mechanism mediating learning and memory
- -synaptic potentiation and depression must be balanced
- learning should occur primarily through synaptic potentiation during wake, leading to synaptic strength
- leads to potential saturation of synaptic structures if left unchecked - “the price our brain pays for learning”
- -during sleep, synaptic spine head volume, area of axon/dendrite interface, dendritic spine density all decrease
who benefits from sleep?
young, healthy adults
-increased declarative consolidation with SWS
-increased procedural consolidation with stage 2 non-REM
adults with chronic stroke
-benefit to implicit and explicit task variations
adults with brain injury
-mechanisms underlying sleep-dependent consolidation benefits are not yet known
who does not benefit from sleep?
older, healthy adults show little off-line sleep-dependent improvements in spatial learning or fine motor tasks
clinical application for sleep
conduct PT session lateral in day/in evening
quiet environment to ensure better sleep
nap following PT session
assess effects of depression , medication side effects, sleep apnea
influence of exercise on memory
CV exercise contributes to maintaining or enhancing cognitive function
- most powerful influence on executive control tasks involving frontal areas of brain
- recent data show CV exercise triggers biochemical cascade that may enhance memory processing
time-dependent nature of acute CV exercise effects
different stages of memory formation (i.e. encoding, consolidation, recall) facilitated depending on time of exercise performance
acute and long-term CV interventions –> 2 fundamentally different distinct strategies to improve memory
timing effects of exercise
exercise bout performed before or during learning exposure activates mechanisms that lower threshold for acquisition (encoding)
-exercise effects may persist after exercise
–may influence initial consolidation process
–largest effect of acute exercise on memory occur with delayed retention (vs. immediate retention)
long-term CV exercise does not improve memory significantly
-does have priming effect of mechanisms for memory processing
–optimizes effect of a single bout of acute exercise
what molecular mechanisms that are involved in encoding and consolidation are primed after a single bout of acute CV exercise
dopamine -short-term epinephrine -long-term retention Brain-Derived Neurotrophic Factor (BDNF) -short and long term
BDNF
-functions
regulates survival and differentiation of neuronal populations during development
promotes differentiation, neurite extension, and survival in HIPPOCAMPUS, striatum, and cerebellar neurons
BDNF
- acute effects
- chronic effects
acute -enhance synaptic transmission -neuronal excitability -i.e. makes neurons easier to fire chronic -protein synthesis (mRNA translation/transcription) --> architectural modification of motor centers
