brain: consumer of energy and blood flow
2% of BM but consumes 20% E at rest, 15% of CO, dev brain increases 4x from birth, 50% E and CO at rest, fully dev by 3rd decade of life
lifelong brain plasticity
lifelong capacity to grow and change through experiences, neurogenesis to grow new neurons, synaptogenesis creates and strengthens connections between neurons, angiogenesis grows new BV to support brain tissue; all impact cog function
cognitive function
process recognizing and acquiring ideas and knowledge to understanding world through thought and exp; includes org and planning, problem solving, memory, reaction time, etc.
global cognition
general intelligence; fluid (executive function reacting to world and making decisions to learn, include working memory, processing speed, attention, vis spatial memory, etc.) + crystallized cognition (application of knowledge gained through past exp, include language, verbal intellect, reading abilities, and semantic knowledge)
measuring cognition using cognitive tests
1. overview
2. how to conduct
3. limitations
- measures specific domains of cog such as attention or working memory or global neurocog function
- pen/paper, computer apps, motor tasks
- learning/familiarization (esp relevant to concussion) and language, hearing, and visual abilities have influence on scores, many different tests in same domain makes it hard to compare between tests
Montreal Cognitive Assessment
screening tool for cognitive impairment measuring visuospatial abilities, language, memory, and executive functions, easy and quick to administer, accounts for education effect on cog, score cutoffs for normal, mild cog impairment, and dementia
Eriksen Flanker task
on computer or tablet must tell direction middle object is facing in congruent (all same way), incongruent (others opp way), or neutral (others no direction) with distractors, test for inhibitory control, selective attention, and processing speed
Stroop test
reading is automatic, suppress drive to read and say colour of ink, congruent colour matches ink, incongruent colour does not match ink, neutral word is not colour, test for selective attention and processing speed
trail making test
measure time to task completion, version A connect numbers in sequence, version B more complex connecting number to letter number in sequence, tests task-switching, visual search, and processing speed
digit-symbol substitution test
correct answers in 90 sec, for acute impairment, matching symbols to appropriate number in bank as fast as possible, test for working memory, attention, visual search abilities, and processing speed
fMRI and EEG
- fMRI measures blood oxygen level dependent response to cognitive testing stimuli, surrogate for brain activity, good spatial resolution but poor temporal resolution
- EEG uses electrodes to measure neuron electric activity in response to cog challenge, good temporal resolution but poor spatial resolution
impacts of cognitive function and cognition across the lifespan
- genetics, in-utero exposures, early life experience (passive and active higher cog conversations with parents), SES, parental edu, enviornmental factors
- lifestyle choices such as diet, PA, sleep, and drugs
- cog function peaks around 25 and declines with age, difference between ideal and real cog function trajectory is cognitive reserve, interventions at any age can boost cog func and slow decline
PA and developing brain
children with higher PA have better cog function (more gray and white matter, esp bigger hippocampus for better memory, learning, and decision making) and perform better academically, lower level of mental health issues,
exercise on aging brain
1. aerobic fitness
2. dementia
3. risk of neurological disease
- higher VO2peak protects against natural decline of brain tissue with age
- adults without cog impairments at baseline, follow up 6 yrs later, >3x exercise 34% more likely to be dementia and alzhemier’s free
- APOPE E4 homozygote high risk, E4 hetero/non-carrier low risk alzhemier’s, exercise not impact for hetero and non-carriers but sig lower risk for exercising homozygotes; beta amyloid is biomarkers for Alzhemier’s, E4 pos non exercises high B amyloid, E4 pos exercisers and E4 neg low B amyloid; exercise buffers dev risk of neurological disease
brain and movement
1. how brain facilitates motion
2. early humans
- movement req surveillance of environment, rapid decision making, and high deg of coordination facilitated by brain
- moved large distances for basic needs, learn and remember successful strategies, socially coordinate and cooperate
effect of exercise on the brain during and after bout
- during increases neural firing and cerebral BF
- acutely after increases arousal, circulating BDNF, cog func, and feelings of well being, primes brain for subsequent activity
- overtime exercise training has chronic effects of increased brain plasticity, improved cog and mental health, and decreases risk of neurological disease
exercise and improved cognition
1. duration
2. testing timing, cog domain, and modality
- young males do cont moderate intensity cycling or 30 mins of reading, exercise group has greater improvement in cog function than control, sig better response time and accuracy at 20 mins cycling, 45 mins faster reaction (more arousal) but more fatigued so sig drop in accuracy
- benefits 11 mins after exercise, most benefits at 11-20 mins post and when exercise >30 mins, all cog domains most benefit for executive functions, aerobic combined with RT or flexibility superior to single modality
exercise intensity and improved cognition
1. catecholamine hypothesis of intensity cog inverted U relationship
2. physical fitness
- moderate exercise highest cog performance, exercise increases realase of dopamine and catecholamines from reticular formation to drive improved cog, over-arousal from high intensity worsens performance since need to recover from exercise bout
- fitness buffers over-arousal higher cog during and after high intensity exercise since brain is better adapted to handle high intensity stressor due to repeated exposure thus have higher cognition, see greater improvements in cog after exercising at high intensity
altitude exercise on cog function
1. methods
2. results
3. implications
- low altitude and high altitude (60% O2 at sea level) groups, measured cog at baseline and 10 mins post 20 min mod aerobic exercise
- groups same at baseline, cog function decreased following 20 mins of exercise at high altitude
- altitude may have impact on safety and decision making
acute PA on brain function in children with ADHD
20 mins treadmill or reading, EEG to get brain activity during cog test, immediate improvements in selective attention and standardized academic tests for both groups with exercise, ADHD sig worse with reading and better benefit on attention than neurotypical children post-exercise
HIIE on cognition in university students
- 11 min HIIE or control waiting, then do cog test, faster processing speed, greater speed and accuracy on selective attention, fewer errors following HIIE
- HIIE or control before lecture, wrote quiz related to lecture hrs later, no difference between groups since how people study and engage with material best is different, not same as cog test
exercise training on hippocampus in aging
1. effects on hippocampal growth
2. RT and plasticity of aging brain
- increases hippocampal growth, improved memory, pos correlation with increased BDNF for exercise induced brain plasticity in older adults
- RT once or twice a week, both groups sig improvement executive function, selective attention, conflict resolution, in twice group greater brain activity during cog test, causing functional reorg and improving cog
PA and environmental enrichment on cognition
1. hippocampal neurogenesis in mice
2. order of combined traning in humans
- exercise and environmental enrichment (cog challenge) both increase cog, exercise stimulates neurogenesis, enrichment promotes survival of neurons by using them
- single condition or combined PA and cog test (exercise first and cog first) over 12 weeks, exercise and cog training improved cog regardless of order, exercise along showed lowest improvement since less familiar with cog testing
