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Psychology 20Unit 2 - Who Am I?
Neuroscience, The Brain & Behaviour
Neurons: special long, thin cells that move information within the brainAxon: the part of neuron that transports the ‘neural’ messageMyelin Sheath: fatty tissue that covers axons to help transport messages fasterDendrites: the ‘bushy/branchlike’ extensions of a neuron that receive brain messages
Brain Cell Overview:
Picture: ‘A Child’s Brain - The Need for Nurture’ - R. Sylwester (2010)
Organization of the Human Brain
Picture: ‘A Child’s Brain - The Need for Nurture’ - R. Sylwester (2010)
Cerebellum: controls posture & balance.Brainstem: the ‘central core’ of the brain. Responsiblefor automatic survival functionsCorpus Callosum: nerve fibres that connect and transfer messages between the two hemispheres of the brain.Cerebral Cortex: controls higher brain function, likereading & problem solving. Hypothalamus: controls the ‘autonomic’ nervoussystem (eating/drinking/temperature).Thalamus: controls incoming messages into the brainand sends them to the different parts of the brain.Cingulate: controls ability to learn, memory andemotions. (aka - Cerebrum)
The Cerebral LobesFrontal Lobe: lies just behind forehead. Controls speaking , muscle movement, reasoning, inhibitions and personality.Motor Cortex: controls voluntary movements (things you have to think about to move.)Temporal Lobe: controls hearing
Occipital Lobe: controls eye sight
Who was Phineas Gage?
Picture: ‘A Child’s Brain - The Need for Nurture’ - R. Sylwester (2010)
Brain Functions
diagram: Psychology - David Meyers (2004)
Why are humans such high level thinkers?
Strokesdefinition: the rapid loss of brain function due to a disturbance in
the blood supply to the brain.
Two Kinds of Strokes
Ischemic: blood supply to part of the brain is decreased.examples: thrombosis & embolism
Hemorrhagic: accumulation of blood anywhere within the skull.example: aneurysm
note: 83% of all strokes are Ischemic
Stroke Videos
• Understanding Strokes• Risk Factors for Strokes• Symptoms of a Stroke• Effects of Strokes
Seizures
Epilepsy: is a common chronic neurological disorder characterized by seizures.
- 50 million people worldwide have epilepsy- epilepsy becomes more common as people age
- epilepsy occurs most frequently in infants and the elderly- seizures often occurs in people recovering from brain surgery/brain injury
- epilepsy is usually controlled, not cured, with medication- epilepsy is caused by abnormal electrical activity in the brain
Wikipedia, 2011
Human Nervous System
Cheesy nervous system video!
Human Endocrine Systemdefinition: body’s ‘chemical’ communication system ... a set of
glands that release‘hormones’ into the bloodstream
diagram: Psychology - David Meyers (2004)
QuickTime™ and aNone decompressor
are needed to see this picture.
Inside the Teenage BrainDocumentary
Chapter 1 - Teenager’s Inexplicable BehaviourChapter 2 - Wiring of the Teenage Brain
Chapter 3 - Mood SwingsChapter 4 - “You Just Don’t Understand”
Chapter 5 - From Zzzzz’s to A’sChapter 6 - Are There Lessons For Parents?
Inside the Teenage Brain - IMPORTANT POINTS
• magnetic resonance imager (MRI)
• hippocampus: plays an important role in short & long term memory and spatial navigation
• from childhood through one’s teen years the brain is undergoing very, very rapid development.
• just before puberty there’s even more significant growth in the frontal cortex.
• “By age 6, the brain's already 95 percent of its adult size. But the gray matter or thinking part
of the brain continues to thicken throughout childhood as the brain cells grow extra connections,
much like a tree growing extra branches, twigs and roots.” (PBS, Inside the Teenage Brain,
2002)
• Brains grow like trees … lots of ‘furry’ growth and then pruning, called ‘neural pruning.’
• Neural pruning leads to the ‘use it or lose it theory.’
• Neurologists are very interested in the teen’s frontal cortex – the part of the brain responsible for:
- planning behaviours
- strategies
- problem solving
… all the above is called ‘cognitive flexibility’
• teens that are 13, 14 & 15 have an ‘immature’ frontal cortex … could explain why teens are such
risk takers.
• teens and adults read emotion differently … through MRI examinations adults and teens
interpreted the following picture differently:
- adults identified the emotion as ‘fear’
- teens identified the emotion as ‘shock’ or ‘anger’
• this mis-reading of emotion could be a cause of the ‘gap of understanding’ between teens and their
parents.
• the part of the brain responsible for emotions is much more ‘activated’ in teenagers.
• the teen’s cerebellum is the part of the teen’s brain that changes the most over the teen years. (The
cerebellum is in the lower-back portion of the brain.) The cerebellum has always been known to
coordinate our muscles, but recent studies have shown it to coordinate our thoughts as well.
• teens build up huge ‘sleep debts’ during the teen years. Because of technology, etc. teen’s sleep is
being forced into a smaller and smaller window.
• the teen’s ‘circadian clock’ helps prop them up at the end of the day. A circadian clock can be
defined as one’s biological timing system.
• circadian clocks shift forward as children move into their teens.
• there’s a direct correlation between the amount of sleep a teenager gets and his or her performance
at school.
• our sleep is divided generally into two stages:
- rapid eye movement (REM)
- non-rapid eye movement (NREM)
• NREM is split into stages N1, N2 & N3
• Sleep proceeds in cycles of REM and NREM, the order normally being N1 → N2 → N3 → N2 →
REM. There is a greater amount of deep sleep (stage N3) earlier in the sleep cycle, while the
proportion of REM sleep increases later in the sleep cycle and just before natural awakening.
• dreaming occurs mostly during REM sleep.
• teenagers require between 9 & 10 hours of sleep nightly.
• sleep disorders:
- sleep apnea: abnormally low breathing during sleep
- narcolepsy: excessive daytime sleepiness
- insomnia: having great difficulty falling or staying asleep
- periodic limb movement disorder
- restless leg syndrome
• teens build up huge ‘sleep debts’ during the teen years. Because of technology, etc. teen’s sleep is being forced into a smaller and
smaller window.
• the teen’s ‘circadian clock’ helps prop them up at the end of the day. A circadian clock can be defined as one’s biological timing
system.
• circadian clocks shift forward as children move into their teens.
• there’s a direct correlation between the amount of sleep a teenager gets and his or her performance at school.
• our sleep is divided generally into two stages:
- rapid eye movement (REM)
- non-rapid eye movement (NREM)
• NREM is split into stages N1, N2 & N3
• Sleep proceeds in cycles of REM and NREM, the order normally being N1 → N2 → N3 → N2 → REM. There is a greater amount of
deep sleep (stage N3) earlier in the sleep cycle, while the proportion of REM sleep increases later in the sleep cycle and just before
natural awakening.
• dreaming occurs mostly during REM sleep.
• teenagers require between 9 & 10 hours of sleep nightly.
• sleep disorders:
- sleep apnea: abnormally low breathing during sleep
- narcolepsy: excessive daytime sleepiness
- insomnia: having great difficulty falling or staying asleep
- periodic limb movement disorder
- restless leg syndrome
Is Driving Tired More Dangerous ThanDriving Tipsy?
Do We Only Use 10% of Our Brain?
‘The Downside of High’ Documentary
Teenagers who start smoking marijuana before the age of sixteen are four times more likely to become schizophrenic. That's the startling conclusion of some of the world's top schizophrenia experts, whose research is featured in the new documentary The Downside of High.
The scientists' groundbreaking work on the connection between marijuana and mental illness also reveals that, for all young adults, smoking marijuana nearly doubles the risk of developing recurring psychosis, paranoia and hallucinations - the hallmarks of schizophrenia.
FACTS
- Schizophrenia: A mental illness featuring recurring psychosis and a breakdown in the relation between thoughts, feelings and actions, usually accompanied by a withdrawal from social activity.
- Psychosis: A disordered mental state involving a loss of contact with reality, frequently with hallucinations, delusions or altered thought processes. Psychosis is a symptom of schizophrenia. Psychosis is a tendency to attribute too much meaning to mundane and neutral events.
- Dopamine: A neurotransmitter in the brain that affects emotion, mood, perception and movement.
- Tetrahydrocannabinol - THC - the main psychoactive ingredient in the cannabis plant. THC can cause psychosis.
Glossary:
‘The Downside of High’ DocumentaryImportant Points
- Can smoking pot make kids psychotic?
- Elevated levels of ‘dopamine’ in brain of patient who smoked pot before a brain scan in 1999, created a link between marijuana and schizophrenia
- A British journalist made connections between cannabis and schizophrenia in the 1980’s after talking to families of troubled kids
- 50 000 Swedish military recruits were followed in a study in the 1980’s to study the link as well. (The more cannabis they smoked at the age of 18 the higher the chance of being diagnosed with schizophrenia over the next 15 years … 6 times more likely to develop schizophrenia than someone who has never smoked the drug.)
- Schizophrenia: A mental illness featuring recurring psychosis and a breakdown in the relation between thoughts, feelings and actions, usually accompanied by a withdrawal from social activity.
- Psychosis: A disordered mental state involving a loss of contact with reality, frequently with hallucinations, delusions or altered thought processes. Psychosis is a symptom of schizophrenia. Psychosis is a tendency to attribute too much meaning to mundane and neutral events.
- Dopamine: A neurotransmitter in the brain that affects emotion, mood, perception and movement.
- Tetrahydrocannabinol - THC - the main psychoactive ingredient in the cannabis plant. THC can cause psychosis. The level of THC in today’s marijuana is 18 to 25%, compared to 1 to 3% in the 60s and 70s. Today’s marijuana is so potent that the United Nations is considering classifying it as a different drug than what was consumed in the 1960s.
- Majority of pot smokers suffer no side affects. For some though it sends them into a state of paranoia & sometimes psychosis.
- Marijuana use doubled in the USA and Canada in the 1990’s.
- Bi-polar disorder: a mental illness characterized by large mood swings and psychosis
- Marijuana is the most widely used drug in the world.
- Marijuana cannot trigger mental illness on it’s own. Other ‘background factors’ contribute as well … family history of psychosis/mental illness, using upper drugs, experiencing childhood trauma, living in urban areas, etc.
- Many marijuana studies take place in the Netherlands, because of the legality of the drug there.
- Dutch researchers are scanning the brains of marijuana smokers to find a biological basis for their belief that pot causes schizophrenia. More specifically they’re studying the impact on dopamine of drug users in the brain, as pot drives up dopamine levels.
- Cannabinoids: A group of compounds appearing in the cannabis plant, but also present naturally in the nervous and immune systems of humans. The human cannabinoid system is overwhelmed when we smoke marijuana
- Neural pruning: A neurological process occurring during the teen years that reduces the number of the brain’s overproduced or ‘weak’ neurons and reorganizes the synapses’ configurations – somewhat like defragmenting a computer.
- Is there confusion between cause and effect … does marijuana mask the early symptoms of mental illness?
- Prodromal: The earliest symptoms of a disease.- COMT gene - the schizophrenia gene? It regulates dopamine levels in the brain. If you have the low functioning version of the COMT gene you have trouble regulating dopamine in the brain. (ie. You get highs and lows.)
- Why haven’t we seen a jump in psychotic illnesses with the extremely strong pot being smoked around the world? Hard to measure mental illness?- Some schizophrenics take marijuana to relieve symptoms. Unfortunately, you get calm at first, but have worse psychotic episodes later.
- Cannibidiol: A chemical in the cannabis plant that reduces or buffers the psychoactive effects of THC.
- No regulation of marijuana’s potency in the Netherlands, nor the amount of CBD
