Behavioral Neuroscience: Lecture 4 2/02/04. Discussion: Genes and Behavior §Are abilities based in...
-
Upload
elwin-oneal -
Category
Documents
-
view
222 -
download
0
description
Transcript of Behavioral Neuroscience: Lecture 4 2/02/04. Discussion: Genes and Behavior §Are abilities based in...
Behavioral Neuroscience:
Lecture 4
2/02/04
Discussion: Genes and BehaviorAre abilities based in biology or the environment?
Can genes predict success (divorce, intelligence, health, career)?
What if genotypic information was as readily available as your phenotype? Should health care providers or employers
have access to our genotypic information?
Phineas Gage
September 13th, 1848Phineas = 25Rutland & Burlington Railroad, Cavendish, VTPaving the way for new RR tracks“Tamping Iron”
1.25 x 3ft
Phineas Gage: . the historical beginnings of the study of the biological basis of behaviorAccident
Quick RecoveryMonths later: “No longer Gage”
Capable, efficient, best foreman, well-balanced mind Extravagant, anti-social, liar, grossly profane
Stint with P.T BarnumCarriage driver in ChileDied 12 years later
“Intellect unimpaired”
Frontal lobe involved in thinking, planning, setting goals, inhibiting impulses
The brain is not a single or simple entity It’s an integrated system with different specialized
parts Links can be revealed by damage to specific
structures Every sight, sound, taste, twitch, dream, memory,
thought, etc. is biological
How does communication occur?
Electrochemical communication between brain, sensory organs, muscles, and glands
Nervous systemThe Neuron
Structure Action Communication
Brain
THE HUMAN BRAIN: Centerpiece of Nervous System
BRAIN AT BIRTH ==> 25% of adult weight
CONTAINS MOST OF THENEURONS
YOU WILL EVER HAVEABOUT
100 BILLION NEURONS100,000,000,000
Communication NetworksBroad overview: 3 functions
Solve survival problems Receive & transmit signals (brain-body)
Automatically regulates internal states
Transmit from sensory to CNS
Fight or Flight Restore
Sympathetic and parasympathetic divisions of nervous system
Specific Parts: The Neuron Structure
Neurons = building blocks of nervous system
Specific Parts: The Neuron Function
Neurons = 3 functions: Reception, Conduction, Transmission
1.3.
2.
Sensory Neurons (afferent) Neurons that send signals from the senses,
skin, muscles, and internal organs to the CNS
Motor Neurons (Efferent) Neurons that transmit commands from the
CNS to the muscles, glands, and organs
Types of Neurons:
The Withdrawal Reflex
NOTE: Not just one neuron at a time
Complex networks of thousands of neurons sending and receiving are basis of all psychological activity Neural networks = habits
Action I
Messages occur in form of electric impulses http://homepage.psy.utexas.edu/homepage/class/Psy301/Pennebaker/DailyOutlines/Sept08%20Stress/neuricon.gif
Neuron =
Every neuron has membrane Some ions permeate more easily
• Na+ do NOT pass easily• K+ DO pass easily
Resting state = Negative• Negatively charged ions permanently trapped inside cell
W. W. Norton
Action Potential
When dendrites stimulated (IF enough stimulation**)
Delicate balance altered Membrane breaks down Positively charged ions rush in (depolarization)
• Charge = less negative• Action Potential
– Quick burst of electrical energy surges down axon
Relay Race
Action Potential starts at dendrite Through cell body Down Axon Axon Terminals
• How does it get to the next cell’s dendrites?
• Neurons don’t touch–Synapse = millionth inch gap–In synapse = vesicles w/ Neurotransmitters
»Chemical messengers that transmit info
Communication Impulse releases
neurotransmitter from vesicles.
Neurotransmitter enters synaptic gap.
Neurotransmitter binds to receptors on the receiving neuron.
Neurotransmitters
Can be inhibitory or excitatoryWon’t stop until:
Reuptake Enzyme deactivation Autoreception
Neurotransmitters (>75)Acetylcholine (ACh)
1st substance identified as NT Links motor neurons and muscles (contract or relax)
• e.g. curare vs black widow spider Also involved in memory, learning, sleep, dreaming
Endorphins (the brain’s own morphine) 1973 injected rats with morphine Bound like NTs Brain had receptors for exogenous substance?
• Brain must produce its own morphine• Released during pain and discomfort
One Brain or Two?
Right and left sides have different strengths? Right- visual, spatial tasks Left- Reading, verbal processes
Each hemisphere controls opposite side?What if the two sides were disconnected?
“split-brain patients”
Case Study: WJ
1961, W.J. comes to the labCards & blocks
2 red sides 2 white 2 mixed
Use 1 hand to assemble blocks Left hand success vs. right hand success??
Acting as 2 separate brains…
Left hand- YES!Right hand- NO!
Sometimes Left would sneak up to help right! “Each half brain worked outside the conscious
realm of the other”
LATERALIZATION
WHICH FUNCTIONS? Left:
• Adult speech• Literal interpretation• Analytical thinking
Right:• Visual & Auditory patterns• Interpretation of subtleties• Holistic thinking• Face Recognition
The lobes of the cerebral hemispheres
The lobes of the cerebral hemispheres
Planning, decision making speech
Sensory
AuditoryVision