THE BIOLOGY OF THE MIND. BIOLOGICAL PSYCHOLOGY UNDERSTANDING SLEEP, DREAMS, DEPRESSION, HUNGER,...
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Transcript of THE BIOLOGY OF THE MIND. BIOLOGICAL PSYCHOLOGY UNDERSTANDING SLEEP, DREAMS, DEPRESSION, HUNGER,...
THE BIOLOGY OF THE MIND
BIOLOGICAL PSYCHOLOGYUNDERSTANDING SLEEP, DREAMS, DEPRESSION, HUNGER, STRESS,
& SEX
• Everything psychological is simultaneously biological• Thoughts, emotions,
memories, intelligence, and creativity are based on biological processes
• To understand our behavior, we need to study how biological, psychological and social systems interact.
THE NERVOUS SYSTEM
It starts with an individual nerve cell called a NEURON.
Sensory neurons Carry incoming messages from the body’s tissues and
sensory organs inward to the brain and spinal cord, for processing
Motor neurons Carry outgoing information from the brain and spinal cord to
the body’s tissues, muscles, glands
Interneurons Neurons within the brain and spinal cord that communicate
internally between sensory inputs and motor outputs
NEURAL COMMUNICATION
WHEN DO NEURONS TRANSMIT MESSAGES?
Stimulated by: Signals from senses Chemical signals from neighboring
neurons
Action potential Brief electrical charge that travels down
axon
Threshold – minimum intensity Excitatory signals – stimulate
Increase likelihood neuron will fire
Inhibitory signals – calm Decrease likelihood neuron will fire
http://www.youtube.com/watch?v=cNaFnRKwpFk
HOW NEURONS COMMUNICATE
• Synapse• Meeting point between neurons
• Neurotransmitters• Chemical messengers
• Acetylcholine (Ach)• Best-understood neurotransmitter• Messenger between motor neuron and skeletal
muscle• Released = muscle contraction• Blocked = paralysis
http://science.education.nih.gov/supplements/nih2/addiction/activities/lesson2_neurotransmission.htm
Neurotransmitter
Function Examples of Malfunctions
Acetylcholine (Ach)
Enables muscle action; excretion of certain hormones; anger, aggression, sexuality
ACh producing neurons deteriorate – lack of ACh leads to Alzheimer’s disease
Dopamine
Controlling movement and posture; Impacts mood, learning, attention, and emotion
Excess dopamine - linked to schizophrenia. Starved of dopamine = brain produces tremors, decreased mobility and muscle rigidity (Parkinson’s disease)
SerotoninRegulation of body temperature; Affects mood, hunger, sleep, and arousal
Undersupply linked to depression; Prozac raises serotonin levels
Neurotransmitter
Function Examples of Malfunctions
Norepinephrine
Helps control alertness and
arousal
Undersupply can depress mood
GABA(Gamma-
aminobutyric acid)
Major inhibitory neurotransmitter
Undersupply linked to seizures, tremors,
and insomnia
GlutamateMajor excitatory
neurotransmitter; involved in
memory
Oversupply can overstimulate brain, produce migraines or seizures (why some avoid MSG)
DRUGS & NEUROTRANSMITTERS
• When flooded with opiates, morphine or heroin, brain may stop producing natural opiates• Causes intense discomfort - withdrawals
• Drugs and other chemicals affect brain chemistry at synapses – amplifying or blocking neurotransmitters
• Examples:• Agonist - Black widow venom – floods synapses with ACh• Violent muscle contractions, convulsions, possible death
• Antagonist – Botulin – causes paralysis by blocking ACh release• Botox – smooth wrinkles by paralyzing underlying facial
muscleshttp://thebrain.mcgill.ca/flash/i/i_03/i_03_m/i_03_m_par/i_03_m_par_cocaine.html#drogues
THE NERVOUS SYSTEM
• Central Nervous System• Brain• Spinal Cord• Connects peripheral nervous system to brain
• Peripheral Nervous System• Somatic (skeletal) – controls voluntary muscles• Autonomic – controls involuntary muscles
• Glands and muscles of internal organs• Heartbeat, digestion, etc.
• Sympathetic – Arouses and expends energy• You become alarmed or enraged• Increases heartbeat and raises blood pressure
• Parasympathetic – Conserves energy• Stress subsides • Decreased heartbeat, lowering of blood sugar
THE BRAIN
AM I LEFT OR RIGHT BRAIN DOMINANT?
• Recent studies have revealed no evidence of a stronger left or right-sided brain network• Example: Language• Left hemisphere specializes in picking out the sounds that form words • Right hemisphere is more sensitive to the emotional features of language
• It is true that some functions occur in one side or the other of the brain• Language tends to be on the left (Sounds that form words)• Attention more on the right (Emotional features of language)
Left-BrainLogical
LanguageAnalytic
Right-BrainIntuitive
ExpressiveCreative
CEREBRAL CORTEX
CEREBRAL CORTEX
FRONTAL LOBE
• Associated with:• Reasoning• Motor skills• Higher level cognition• Expressive language
• If damaged:• Changes in socialization
and attention; increased risk-taking
• Example - Used when planning a road trip
CEREBRAL CORTEX
• Example – Figuring out if car will fit into parking spot
PARIETAL LOBE• Associated with:• Processing tactile sensory
information• Pressure, touch, pain
• Processing mathematical, spatial information
• If injured:• Problems with verbal
memory• Problems with language
CEREBRAL CORTEX
OCCIPITAL LOBE• Home to the primary
visual cortex• Associated with:• Interpreting visual
stimuli and information
• If injured:• Visual problems• Difficulty recognizing
objects, identifying colors or recognizing words
• Example – Ability to see a stop sign
CEREBRAL CORTEX
• Example – Responding to another driver honking
TEMPORAL LOBE
• Home to the:• Primary auditory cortex • Interpreting sounds and
language
• Hippocampus• Formation of memories
• If injured:• Problems with memory,
speech perception, and language skills
STORY OFHOW YOU USE YOUR LOBES
• Instructions:• Construct a short story detailing how you use your lobes•Must include reference to all four
•Write story on back page of your brain book
THE BRAINSTEMTHE BRAIN’S BASEMENT
• Brain’s oldest and innermost region
• Brain stem acts as crossover point• Regulates involuntary functions
• Midbrain • Helps to relay information for vision
and hearing• Also associated with motor control,
alertness, and temp. regulation
• Pons• Helps coordinate movement
• Medulla• Controls heartbeat and breathing
THE BRAIN
Cerebellum• “Little brain”• Regulates voluntary
motor movements• Posture, balance,
coordination, speech
Corpus Callosum
• Wide band of axon fibers connecting two brain hemispheres• Carries messages between
←Cerebellum
THE SPLIT BRAINAssists researchers in studying hemispheric
specialization
• 1961 - Neurosurgeons predict epileptic seizures caused by amplified abnormal brain activity between the two hemispheres
THE LIMBIC SYSTEM
• Hypothalamus – controls maintenance• Helps keep the body’s internal environment in a steady state• Hunger, thirst, body temperature, sexual behavior
• Controls the pituitary gland “master gland”• Regulates and releases important hormones
• Hippocampus• Responsible for memory
creation and retention
• Amygdala• Linked to emotion• Influence aggression and fear• Processing of emotional
memories
• Thalamus• Brain’s sensory
switchboard• Relays all sensory
information• Except for smell
THE ENDOCRINE SYSTEM
• Glands secret hormones, chemical messengers
• Travel through bloodstream affecting other tissues
• Influence our interest in sex, food, and aggression
THE ENDOCRINE SYSTEM
• Pituitary Gland• “Master gland”• Located near core of brain• Controlled by hypothalamus
• Releases hormones that influence growth
• Secretes hormones that control output of hormones by other endocrine glands• Triggers sex glands to release
sex hormones
THE ENDOCRINE SYSTEM
•Adrenal gland• Located on top of
kidneys
• Release epinephrine and norepinephrine• Adrenaline and
noradrenaline
• Hormones increase heart rate, blood pressure, and blood sugar• Provide surge of energy
THE ENDOCRINE SYSTEM
• Thyroid gland• Produces thyroxine• Too little – feel lazy, lethargic
• Hypothyroidism
• Too much – overactivity• Hyperthyroidism
• Sex glands• Testes• Produce sperm and
testosterone
• Ovaries• Produce eggs and estrogen
and progesterone
STUDYING THE BRAIN
CAT SCAN
• Computerized axial tomography scan• CAT scan or CT scan
• Combines series of X-ray views taken from different angles to create cross-sectional images
• Can be reformatted into multiple planes or even used to generate three-dimensional images
• Provide great detail of soft tissues and blood vessels
(EEG) - ELECTROENCEPHALOGRAM
Amplified read-out of waves of electrical activity
that sweep across the brain’s surface
• Process:• Stimulus presented regularly• Computer filters out brain
activity unrelated to stimulus• Able to identify electrical wave
evoked by stimulus
• Used in identifying:• Epilepsy• Other brain disorders
PET SCAN(PET) - POSITION EMISSION TOMOGRAPHY
• Shows how the brain and its tissues are working• Depicts brain activity by showing each brain area’s
consumption of its chemical fuel, sugar glucose• Radioactive glucose
• Useful in looking for cancer, disease, or injury to the brain
PET SCAN
• Shows which brain areas are most active during:• Math calculations• Looking at images of faces• Daydreaming
(MRI)MAGNETIC RESONANCE IMAGING
• MRI has revealed:• Larger neural area in left hemisphere of
musicians with perfect pitch• Enlarged fluid-filled brain areas in patients
experiencing schizophrenia
• Head inserted into strong magnetic field
• Allows us to see structures in the brain• Signals provide detailed
picture of brain’s soft tissues
• fMRI (functional MRI)• Can reveal brain function and structure• Comparison of MRI scans taken less than a second
apart• Reveals blood flow – “lights up”
• Person performs different mental functions• Example: • Person looks at scene• fMRI detects blood rushing to back
of brain• Processing of visual information
fMRI – FUNCTIONAL MRI