Download chapter 2- neuroscience genetics and behavior

CHAPTER 2- NEUROSCIENCE GENETICS AND BEHAVIOR
Everything psychological is biological. This perspective is called biological psychologists
or neuropsychologists.
Phrenology -- Franz Gall early 1800’s-study of bumps on the head to determine
character traits. Although this theory was false it did give rise to the idea that different
parts of the brain control different aspects of behavior.
Biological, psychological and social systems work and interact to form our behavior.
A. STRUCTRE OF A NEURON or NERVE CELLS are the BUILDING BLOCKS OF
the nervous systems.
EACH NEURON CONSISTS OF A
CELL BODY
DENDRITES- RECEIVE INFORMATION
AXON- PASSES IT ALONG TO OTHER NEURONS, MUSCLES OR GLANDS
MYELIN SHEATH- A LAYER OF FATTY CELLS THAT INSULATES THE
AXONS AND SPEEDS THEIR IMPULSES (MULTIPLE SCLEROSIS-CAUSED BY
SHEATH DEGENERATING SLOWING MUSCLES)
NEURAL IMPUSE TRAVELS FROM 2-200 MPH. WE MEASURE BRAIN
ACTIVITY IN MILLISECONDS. COMPUTER ACTIVITY IS FASTER BUT YOUR
BRAIN IS MORE COMPLEX.
1. NEURON FIRES IMPULSE WHEN STIMULATED BY PRESSURE, HEAT,
LIGHT OR CHEMICAL MESSAGES. ACTION POTENTIAL-A BRIEF
ELECTRIAL CHARGE THAT TRAVELS DOWN THE AXON LIKE A LINE OF
FALLING DOMINOES
2. IONS- ELECTRICALLY CHARGED ATOMS. FLUID INSIDE A RESTING
AXON CARRIED NEGATIVE CHARGED IONS. THE FLUID OUTSIDE THE
AXON MEMBRANE HAS POSITIVE IONS. .
3. RESTING POTENTIAL- POLARIZATION OF POSITIVE OUTSIDE AND
NEGATIVE INSIDE. WHEN THE NEURON FIRES THE GATES OPEN
ALLOWING THE POSITIVE CHARGED IONS TO RUSH IN.
4. THIS DEPOLARIZES THE PART OF THE AXON, WHICH CAUSES THE
NEXT AXON’S CHANNEL TO OPEN AND THE NEXT FALLING LIKE
DOMINOES.
5. REFRACTORY PERIOD-RESTING PAUSE THE NEURON PUMPS POSITIVE
CHARGED ATOMS BACK OUTSIDE AND THE PROCESS STARTS AGAIN.
(100 TIMES A SECOND)
6. . THRESHOLD- THE LEVEL OF STIMULUS REQUIRED TO TRIGGER AN
IMPULSE. SOME IMPULSES ARE EXCITATORY ACCELERATOR SOME
ARE INHIBITORY (A BRAKE.)IF EXCITATORY MINUS INHBITORY
EXCEEDS THE THRESHOLD THE NEURON TRANSMITS AN ELECTRICAL
IMPULSE.
7. NEURONS REACTION ARE AN ALL OR NONE RESPONSE. THEY EITHER
FIRE OR THEY DON’T.
8. STRONG IMPULSES TRIGGER MORE NEURONS NOT FASTER.
HOW NEURONS COMMUNICATE
1. SYNAPSE THE JUNCTION BETWEEN THE AXON TIP OF THE SENDING
NEURON AND THE DENDRITE OR CELL BODY OF THE RECEIVING
NEURON. SYNAPTIC GAP OR CLEFT.
2. NEUROTRANSMITTERS- CHEMICAL MESSENGERS THAT CROSS THE
GAP ALLOWING THE IONS TO ENTER THE RECEIVING NEURONS EITHER
EXCITING OR INHIBITING ITS FIRING.
Neurotransmitters
1 ACETYlCHOLINE- JUNCTION AT SYNAPSE BETWEEN MOTOR
NEURONS AND MUSCLES. Enables muscle action, learning and memory.
Undersupply neurons deteriorate, Alzhheimers. BOTULIN, BLOCKS ACH. SPIDER
VENOM FLOOODS IT CAUSING CONVULSIONS.
2 ENDORPHINS-BODY’S NATURAL MORPHINE. MORPHINE RELEASED
IN RESPONSE TO PAIN AND VIGOROUS EXERCISE. RUNNERS HIGH.
IF A PERSON TAKES DRUGS OR OPIATES SUCH AS HEROIN THE NATURAL
NEUROTRNSMITTERS OR ENDORPHINS STOP PRODUCING. WHEN THE
DRUG WEARS OFF THE BRAIN IS DEPRIVED CAUSING WITHDRAWL. ALL
DRUGS FROM NICOTINE TO HEROIN INTERFERE WITH THE BODY’S OWN
NEUROSTRANSMITTERS.
3 DOPAMINE- INFLUENCES MOVEMENT LEARNING, ATTENTION AND
EMOTION. EXCESS LINKED TO SCHIZOPHRENIA. LACK OF DOPAMINE
CAUSES TREMORS AND THE DECREASED MOBILITY SEEN IN
PARKINSONS. L-DOPA A RAW MATERIAL THAT CONVERTS DOPAMINE
AND GIVES PATIENTS SOME MUSCLE CONTROL. NOT A CURE.
4. SEROTONIN- AN INHIBITORY NEUROTRANSMITTER THAT IS
INVOLVED IN THE REGULATION OF SLEEP, MOOD, AROUSAL, AND PAIN
REGULATION. LACK OF SEROTONIN IS LINKED TO DEPRESSION.
AGONISTS-MIMIC NEUROTRANSMITTERS=ANTAGONISTS BLOCK THEM.
NERVOUS SYSTEM-THE BODY’S SPEEDY ELECTROCHEMICAL
COMMUNICATION SYSTEM.
1. CENTRAL NERVOUS SYSTEM- BRAIN AND SPINAL CORD
2. PERIPHERAL NERVOUS SYSTEM-LINKS THE CENTRAL NERVOUS
SYSTEM WITH MUSLES AND GLANDS.
PERIPHERAL NERVOUS SYSTEM
. 2 COMPONENTS
1. SKELETAL NERVOUS SYSTEM- CONTROLS BODY’S SKELETAL
MUSCLES VOLUNTARY
2. AUTONOMIC NERVOUS SYSTEM-CONTROLS THE GLANDS AND
MUSLES OF OUR INTERNAL ORGANS. INVOLUNTARY
A. SYMPATHETIC NERVOUS SYSTEM- AROUSES US FOR
DEFMENSIVE ACTIONS- IF SOMETHING SCARES YOU
HEARTBEAT INCREASES, BLOOD SUGAR UP DILATES
ARTERIES.
B. PARASYMPATHETIC NERVOUS SYSTEM PRODUCES
OPPOSITE EFFECTS. CALMS YOU DOWN
CENTRAL NERVOUS SYSTEM- THINKING FEELING AND ACTING
A. SPINAL CORD-HIGHWAY CONNECTING THE PERIPHERAL NERVOUS
SYSTEM TO THE BRAIN.
B. REFLEXES – AUTOMATIC RESPONSES-SINGLE SENSORY NEURON
COMMUNICATES THROUGH AN INTERNEURON TO A MOTOR NEURON.
SENSORY NEURON- INCOMING INFORMATION TO CENTRAL NERVOUS
SYSTEM---Afferent nerves
MOTOR NEURON CARRIES OUTGOING INFORMATION FROM THE
CENTRAL TO MUSCLES AND GLANDS-Efferent nerves
INTERNEURON-CENTRAL NERVOUS SYSTEM NEURONS THAT
INTERNALLY COMMUNICATE BETWEEN SENSORY INPUTS AND MOTOR
OUTPUTS
TOUCH A HOT STOVE THE SENSORY NEURON SENDS MESSAGES
THROUGH INTERNEURONS TO THE MOTOR NEURON TO THE MUSCLES
IN YOUR ARM CAUSING YOU TO JERK YOUR HAND AWAY. IF THE SPINAL
CORD IS INJURED NO SENSORY PAIN OR PLEASURE CAN BE FELT.
NEURAL NETWORKS- INTERCONNECTED NEURAL CELLS
ENDOCRINE SYSTEM- PRODUCES HORMONES- CHEMICAL
MESSENGERS THAT TRAVEL THROUGH THE BLOODSTREAM AND AFFECT
OUR INTEREST IN SEX, FOOD AND AGGRESSIVENESS.
1. ADRENAL GLANDS RELEASE EPINEPHRINE OR NOREPINEPHRINE.
THESE INCREASE HEART RATE, BLOOD PRESSURE AND PROVIDE A
SURGE OF ENERGY.
2. PITUATARY GLAND-CALLED MASTER GLAND CONTROLS GROWTH
AND TRIGGERS YOUR SEX GLAND TO RELEASE SEX HORMONES.
3. THYROID GLAND-AFFECTS METABOLISM.
TOOLS FOR STUDYING THE BRAIN
IN EARLY DAYS PEOPLE STUDIED BRAIN INJURED PEOPLE TO SEE WHERE
THE INJURY WAS AND TO UNDERSTAND THE WORKINGS OF THE BRAIN.
TODAY WE HAVE MACHINES THAT RECORD BRAIN ACTIVITY. SCIENTISTS
USED TOLESION or-DESTROY TISSUE IN THE BRAIN OF ANIMALS TO SEE
THE OUTCOME FOR EXPERIMENTATION.
1. EEG-ELECTROENCEPHLOGRAM-Amplified tracing of brain waves.
2. CT COMPUTED TOMOGRAPHY-X-RAY PHOTOGRAPHYS THAT REVEAL BRAIN DAMAGE
3. PET-SCAN position emission tomography- scan a visual display of brain activity
that detects where a radioactive form of glucose is consumed while the brain functions.
4. MRI-MAGNETIC RESONANCE IMAGING- CREATES COMPUTER
GENERATED IMAGES. SHOWS WHAT HAPPENS IN THE BRAIN DURING
PROBLEM SOLVING.
AREAS OF THE BRAIN
HINDBRAIN- located at the skull’s rear, lowest portion of the brain- consists of the
medulla, cerebellum and pons-involved in sleep arousal
MIDBRAIN-located between hindbrain and forebrain is an area where many nerve fiber
systems ascend and descent to connect the higher and lower portions of the brain. - Made
of the reticular formation and a group of neurons that emit the neurotransmitters
serotonin, dopamine and norepinephrine.
Forebrain-Thalamus, hypothalamus, endocrine and limbic systems and the cerebrum.
BRAIN STRUCTURE—
1. BRAIN STEM- OLDEST PART AND CENTRAL CORE OF THE BRAIN. It
begins where the spinal cord enters the skull. It is responsible for automatic
survival functions. MEDULLA- controls heartbeat and breathing
2. RETICULAR FORMATION- CONTROLS AROUSAL
3. THALAMUS- TRANSMITS MESSAGES TO THE SENSORY RECEVING
AREAS IN THE CORTEX AND TRANSMITS REPLIES TO THE CEREBELLUM
AND MEDULLA. RELAY STATION. Located at the top of the brainstem.
4. CEREBELLUM- EXTENDING FROM THE REAR OF THE BRAIN STEM.
CONTROLS BALANCE AND COORDINATIONof voluntary movement. Non
verbal memory
LIMBIC SYSTEM-at the border of the brainstem and cerebral hemispheres,
associated with emotions and drives.
Lymbic system contains the:
HIPPOCAMPUS- PROCESSES MEMORY
AMYGDALA-INFLUENCES AGGRESSION AND FEAR
HYPOTHALAMUS-HUNGER, THIRST, SEXUAL BEHAVIOR, PLEASURE
CENTERS-controls the glands secretion of hormones in the master gland.
PLEASURE CENTERS
PERHAPS PEOPLE WITH DRUG ADDICTION MAY HAVE A REWARD
DEFICIENCY SYNDROME. A GENETICALLY DISPOSED DEFICIENCY IN THE
BRAIN SYSTEMS FOR PLEASURE WHICH LEADS THESE PEOPLE TO CRAVE
SUBSTANCES.
CEREBRAL CORTEX-COVERING OF THE BRAIN FILLED WITH NEURAL
CELLS THAT ARE THE ULTIMATE CONTROL AND INFORMATION CENTER..
WHAT ALLOWS US TO THINK MORE THAN ANIMALS IS THIS ELABORATE
CORTEX. Cortex is like the bark on a tree covering and protecting the cells inside.
Larger cerebral cortex is seen on higher functioning animals. (humans) 30 billion cells
1/8 inch thick. The cerebral cortex is divided into two halves called hemispheres. GLIAL
cells or glue cells provide nutrients and insulating myelin.
HEMISPHERES OF THE BRAIN ARE DIVIDED INTO
1. FRONTAL LOBE-BEHIND FOREHEAD INVOLVED IN SPEAKING AND
MUSCLE MOVEMENT. CONTAINS THE MOTOR CORTEX
1. PARIETAL LOBE FRONTAL LOBES -TOP AND TO THE REAR—SENSORY
CORTEX
2. TEMPORAL LOBE-JUST ABOVE THE EARS—AUDITORY INFORMATION
FROM OPPOSITE EAR
3. OCCIPITAL LOBES-AT THE BACK OF THE HEAD—VISUAL
INFORMATION FROM OPPOSITE FIELD
MOTOR CORTEX—AREA AT THE REAR OF THE FRONTAL LOBE CONTROLS
VOLUNTARY MOVEMENTS-SEND INFORMATION CAUSING MOVEMENT
SENSORY CORTEX—CONTROLS AND REGISTERS SENSATIONS-RECEIVE
INFORMATION
ASSOCIATION AREAS- INVOLVED IN HIGHER MENTAL FUNCTIONS SUCH
AS LEARNING SPEAKING, REMEMBERING, PROBLEM SOLVING AND
THINKING.
APHASIA-IMPAIRMENT OF LANGUAGE DUE TO DAMAGE OF LEFT
HEMISPHERE
Broca’s area- an area of the left frontal lobe that directs the muscle movements in
speech. Broca found person with damage struggled with speech yet could sing familiar
songs.
Wernicke’s area- language comprehension, speak meaningless words.
Angular gyrus- damage leave people unable to read
Phineas Gage—gunpowder through his frontal lobe could still speak and function but his
personality changed. Irritable, spoke profane language, angry rages, loss of morality.
SPLIT BRAIN RESEARCH
Two hemispheres of the brain are connected by the CORPUS CALLOSUM- A
BUNDLE OF AXONS THAT CONNECT THE TWO HEMISPHERES.
SPERRY CONDUCTED EXPERIMENTS WHERE CORPUS CALLOSUM WAS CUT
AND THERE WAS NO COMMUNICATION BETWEEN HEMISPHERES.
1967 STUDIES DONE ON THE RIGHT AND LEFT BRAIN SHOW- RIGHT
HEMISPHERE RECOGNIZED THINGS IN THE LEFT VISUAL FIELD AND THE
LEFT RECOGNIZED THINGS IN THE RIGHT. EX. SHOWN A PICTURE OF A
SPOON IN THE RIGHT HEMISPHERE THE PERSON COULD NOT SAY WHAT
THEY SAW BUT ASKED TO IDENTIFY OBJECTS BY TOUCH THEY WERE
ABLE TO PICK THE SPOON.
RIGHT HEMISPHERE –COPYING DRAWYINGS RECOGNIZING FACES—
VISUAL PERCEPTIONS AND RECOGNIZING EMOTION.
LEFT BRAIN- SPEECH, LANGUAGE VERBAL
A STROKE IN THE LEFT OF A DEAF PERSON INTERFERES WITH THEIR
ABILITY TO SIGN.
GENETICS AND BEHAVIOR
BEHAVIORAL GENETICS-THE POWER OF GENETIC INFLUENCES ON
BEHAVIOR.
HERITABILITY- PROPORTION OF DIFFERENCE AMONG INDIVIUALS THAT
CAN BE CREDITED TO GENES. EX. IF HERITATILITY IS 50% ON
INTELLIGENCE THAT MEANS THAT 50% OF THE DIFFERENCES AMONG ALL
PEOPLE’S INTELLIGENCE IS DUE TO GENES.
THE MALE SPERM CARRIES 23 CHROMOSOMES
THE FAMALE EGG CARRIES 23 CHROMOSOMES
WHEN THESE UNITE THEY FORM THE 46 CHROMOSOMES THAT CONTAIN
THE MASTER PLAN FOR YOUR DEVELOPMENT.
EACH CHROMOSOME IS COMPOSED OF A COILED CHAIN OF DNA
OUR GENES ARE WHAT MAKE US WHO WE ARE.
EVOLUTIONARY BIOLOGISTS- THE STUDY OF EVOLUTIONARY BEHAVIOR
USING THE PRINCIPLE OF NATURAL SELECTION.
NATURE SELECTS BEHAVIORAL TENDENCIES THAT INCREASE THE
LIKELIHOOD OF SENDING ONE’S GENES INTO THE FUTURE.
BIOLOGICAL GENETICS- GENETIC AND ENVIRONMENTAL INFLUENCES ON
BEHAVIOR.
IDENTICAL TWINS DEVELOP FROM A SINGLE ZYGOTE OR FERTILIZED EGG.
FRATERNAL TWINS – TWO SEPARATE ZYGOTES.
MOLECULAR GENETICS- STUDY GENETIC DISEASES