Brain Plasticity: Understanding the Changing Brain Bryan Kolb and Robbin Gibb Canadian Centre for Behavioural Neuroscience University of Lethbridge, Canada
Background Once seen as a static organ, the brain is now understood to be a dynamic organ that undergoes both acute and chronic changes. These changes are referred to as plasticity. The challenge is to identify principles that may control these changes.
Metaplasticity Experiences are not singular events… Changes early in life set trajectories for brain plasticity for a lifetime.
Neurons ‘ R Us
Cells and Humans Cell Structure 1. Complexity of computations 2. Education 3. Occupation 4. Sex
Principles 1. When the brain changes, this is reflected in behavioural change. This change is known by names such as learning, memory, addiction, maturation, ageing, recovery, dementia, etc.
Principles 2. The cortex is altered by many events including: 1. sensory & motor experience 2. learning 3. gonadal hormones and stress hormones 4. psychoactive drugs 5. natural rewards 6. ageing 7. diet
Experiential Treatments Complex Housing Tactile Stimulation
How can this happen? Experience alters brain activity, expression of genes, brain chemistry, behaviour, and so on. Any one of these can alter connectivity and thus function.
Principles 2. The cortex is altered by many events including: 1. sensory & motor experience 2. learning 3. gonadal hormones and stress hormones 4. psychoactive drugs 5. natural rewards 6. ageing 7. diet
Learning can only occur if the brain changes Examples: -learning someone ’ s name -learning to play golf -learning to play music -learning anything today!
Principles 2. The cortex is altered by many events including: 1. sensory & motor experience 2. learning 3. gonadal hormones and stress hormones 4. psychoactive drugs 5. natural rewards 6. ageing 7. diet
Differences in Cortical plasticity
Gonadal hormones change more than the genitals… Relative volume of cortical regions in women and men This means that females and males should behave differently!
How does this relate to sex differences in behaviour?
Gonadal hormones have effects throughout life As hormones drop in ageing, the effects on brain and behavior reduce. BAD NEWS: The sexes become more similar…
Early Experience alters stress axis Acute, mild Chronic stress stress OR high stress Development of Stress Reactivity Increased Stress Modest Stress Reactivity Reactivity Increased Risk for Heart Reduced Risk for Disease, Type II Diabetes, Disease Alcoholism, Affective Disorders, Brain Aging etc.
Role of Aversive Childhood Experience in Middle-Age Disease Early Aversive Experiences predict both somatic and mental health after age 50 years
Turning Gold into Lead The ACE (Adverse Childhood Experiences) Study. 170,000+ middle-aged adults in USA Findings: 1. ACEs are more common than recognized 2. ACEs have a powerful relation to adult health 50 yrs later.
Turning Gold into Lead Examples of ACEs: -family violence: spousal or child related -parental alcohol or drug addictions -sexual abuse -growing up in a household where someone is in jail -parental chronic depression or other ‘ mental ’ illness -loss of one parent for whatever reason
Outcomes after age 55 Health in midlife is related to ACEs -smoking or other addictions -heart and lung disease -depression -diabetes -hypertension -macular degeneration -psoriasis -suicide (or attempted) -etc The increase in incidence varies from about 3X for smoking to 50X for drug addiction and 50X for attempted suicide with 2+
Principles 2. The cortex is altered by many events including: 1. sensory & motor experience 2. learning 3. gonadal hormones and stress hormones 4. psychoactive drugs 5. natural rewards 6. ageing 7. diet
Psychoactive Drugs Alter the Frontal Lobe Drugs include: nicotine caffeine cocaine antidepressants valium marijuana antipsychotics Morphine anxiolytics and more… Consider metaplasticity…
Drugs and later experience = ? Drug Treatment + = Metaplastic effects
The drugs block the later experience-dependent changes all over the brain.
Principles 2. The cortex is altered by many events including: 1. sensory & motor experience 2. learning 3. gonadal hormones and stress hormones 4. psychoactive drugs 5. natural rewards: food, sex, play 6. ageing 7. diet
Principles 2. The cortex is altered by many events including: 1. sensory & motor experience 2. learning 3. gonadal hormones and stress hormones 4. psychoactive drugs 5. natural rewards 6. ageing 7. diet
How does the ageing brain change? Three types of change: A. Degenerative: 1. Cell death and reduced regeneration
Cell Death in Alzheimer ’ s Disease
How does the ageing brain change? Three types of change: A. Degenerative: 1. Cell death and reduced regeneration 2. Atrophy of cells
How does the ageing brain change? Three types of change: A. Degenerative: 1. Cell death and reduced regeneration 2. Atrophy of cells B. Regenerative: 3. Hypertrophy of cells – GOOD NEWS!!!
Principles 2. The cortex is altered by many events including: 1. sensory & motor experience 2. learning 3. gonadal hormones and stress hormones 4. psychoactive drugs 5. natural rewards 6. ageing 7. diet: vitamin/mineral supplements
Principles 3. By understanding how the normal brain changes in response to experience, it is possible to stimulate functional “ recovery ” after cortical injury, other disease, or ageing.
Brain Plasticity through the Lifespan: Opposing Progressive and Regressive processes Progressive (Gain or Growth) Regressive (Loss or Decline) • Loss of neurons and • Neurogenesis glia • Synaptogenesis • Synaptic Pruning • Myelination Lifelong process of change is multidimensional and multidirectional
Risk of Brain Injury over the Lifespan
Zone of Possible Cognitive Development in Adulthood
Possible Cognitive Development of an Individual
More Physical Exercise-Body & Mind
Activity • Intellectual • Social • Physical
Intellectual Activity • Challenging brain to learn, remember, problem solve, create • Brain Fitness Program-POSIT science has clear benefits on memory and understanding • Challenges often ramp up stress hormones above baseline but less than stressful situations • Slight stress enhance our abilities to learn and remember
Social Activity • Participation in social activity is associated with better cognitive function • Social activity outside family contact have biggest positive effects • Social interaction ramps up stress hormones to optimize brain function and social adaptation
Physical Activity • Aerobic training- BDNF • Resistance Training- ILGF Reduced risk of Falls and limb fractures • Training intervals varied but modest regular exercise- brisk walking 30min 5 X per week resulted in improved memory and cognition scores - good retention of improvements
Effect of Physical Exercise on Mental Tasks
Good Diet
Diet • Older people often lose appetite or become less interested in preparing wholesome food • Less folic acid and Vit B-12 associated with cognitive decline • Omega 3 and 6 help maintain health myelin- therefore healthy connections • Antioxidants (Vit C ,E) reduce oxidative stress
Diet • choline in diet - translates into enhanced production of Acetylcholine • loss of ACh implicated in AD • Loss of appetite often related to loss of sense of smell • Food doesn't taste as good if you can't smell it • Loss of sense of smell predicts cognitive decline • Loss of sense of smell can precede onset of Parkinson's or AD by 10 years or more • Lowered ability to identify odors is associated with lower cognitive function at the time of testing
Sleep Well
Sleep • Most people don't get enough • Significant link to how well someone sleeps and their overall health and function • Sleep deprived people have poor regulation of hormones - appetite and hunger • People who do not get enough sleep do not live as long as those who • 1/5 MVA are caused by drowsiness
Sleep and Memory-Stickgold, Harvard • Adequate sleep • Adequate sleep before following learning you attempt to learn something new • Consolidates the learning • Better attention • Strengthens connections • Better motivation in the brain • Better grasp of the new • Only effective concept or task immediately after learning (1st night)
Sleep dysregulation • Disrupted sleep cycles more common as we age • Significant disruption associated with increased risk of schizophrenia, AD and other mental disorders • Shift workers have more disruption of circadian cycles- also more likely to develop cancers
Sleep dysregulation • Sleep apnea- wake up tired, headache, unable to learn • Don't breathe while sleeping • Sleep clinics provide testing • Get a machine that helps you breathe • Apnea untreated results in loss of brain cells-early dementia
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