Brain Plasticity: Understanding the Changing Brain Bryan Kolb and - - PowerPoint PPT Presentation

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

• 1. Complexity of

computations

• 2. Education
• 3. Occupation
• 4. Sex

Cells and Humans

Cell Structure

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.

• 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

Principles

Experiential Treatments

Complex Housing Tactile Stimulation

How can this happen?

Experience alters brain activity, expression

• f genes, brain chemistry, behaviour,

and so on. Any one of these can alter connectivity and thus function.

• 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

Principles

Learning can only occur if the brain changes Examples: -learning someone’s name

• learning to play golf
• learning to play music
• learning anything today!

• 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

Principles

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

• n brain and behavior reduce.

BAD NEWS: The sexes become more similar…

Chronic stress OR high stress Acute, mild stress

Development of Stress Reactivity Modest Stress Reactivity

Reduced Risk for Disease

Increased Stress Reactivity

Increased Risk for Heart Disease, Type II Diabetes, Alcoholism, Affective Disorders, Brain Aging etc.

Early Experience alters stress axis

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+

• 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

Principles

Psychoactive Drugs Alter the Frontal Lobe

Consider metaplasticity…

Drugs include: nicotine caffeine cocaine antidepressants valium marijuana antipsychotics Morphine anxiolytics and more…

Drugs and later experience

Drug Treatment +

= ?

= Metaplastic effects

The drugs block the later experience-dependent changes all over the brain.

• 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

Principles

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!!!

• 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

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)

• Neurogenesis
• Synaptogenesis
• Myelination

Regressive (Loss or Decline)

• Loss of neurons and

glia

• Synaptic Pruning

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

• Intellectual
• Social
• Physical

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

Intellectual 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

Social Activity

• Aerobic training- BDNF
• Resistance Training- ILGF Reduced risk
• f 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

Physical Activity

Effect of Physical Exercise on Mental Tasks

Good 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
• f 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

Diet

Sleep Well

• 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

• Adequate sleep before

you attempt to learn something new

• Better attention
• Better motivation
• Better grasp of the new

concept or task

• Adequate sleep

following learning

• Consolidates the

learning

• Strengthens connections

in the brain

• Only effective

immediately after learning (1st night)

Sleep and Memory-Stickgold, Harvard

• Disrupted sleep cycles more common as we

age

• Significant disruption associated with

increased risk of schizophrenia, AD and

• ther 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

Sleep dysregulation

Control Blood Pressure

Positive Attitude

Emotional Support—Positive Relationships

Music and the Brain

Daily music listening improves auditory and verbal memory, Attention, and mood as well as increasing brain plasticity.

Gainful Employment or Volunteering to make a difference

Challenge your brain

Aging Successfully

• Not just the length of your life that is important
• Quality of life contributes to aging

successfully

• Maintenance of good physical

health – Maintenance of good psychological well being – Both maximize span of effect functioning

– Effective Cognitive Functioning increases quality of life*