Download Brain

Chapter 3
Biological Foundations of Behavior
© 2011 The McGraw-Hill Companies, Inc.
Chapter Preview







Nervous System
Neurons
Brain
Endocrine System
Damage, Plasticity, and Repair
Genetics and Behavior
Biological Foundations and Health and Wellness
© 2011 The McGraw-Hill Companies, Inc.
Nervous System
Neuroscience…study of the body’s
electrochemical communication circuitry
Characteristics of the nervous system




complexity
integration
adaptability (plasticity)
electrochemical transmission
© 2011 The McGraw-Hill Companies, Inc.
Nervous System: Pathways
Afferent Nerves
carry information  spinal cord and brain
Efferent Nerves
carry information  muscles
© 2011 The McGraw-Hill Companies, Inc.
Nervous System: Divisions
Central Nervous System (CNS)

brain and spinal cord
Peripheral Nervous System (PNS)


somatic nervous system – sensory nerves
 muscular activity
autonomic nervous system – internal organs
 sympathetic nervous system – arouses
 parasympathetic nervous system – calms
© 2011 The McGraw-Hill Companies, Inc.
Nervous System: Divisions
© 2011 The McGraw-Hill Companies, Inc.
Nervous System - Cells
Neurons



information processing
about 100 billion in brain
mirror neurons (in primates)
Glial Cells

provide support and nutrition
© 2011 The McGraw-Hill Companies, Inc.
Neurons: Structure

cell body

dendrites

axon

myelin sheath
© 2011 The McGraw-Hill Companies, Inc.
Neurons: Structure
© 2011 The McGraw-Hill Companies, Inc.
Neural Impulse
Axons




ions/ion channel
negatively/positively charged
semipermeable membrane
polarization
Resting Potential

stable charge of an inactive neuron
© 2011 The McGraw-Hill Companies, Inc.
Neural Impulse
Action Potential





depolarization (ion channel opens)
repolarization
ion exchange sweeps along length of axon
all-or-none principle
once initiated, cannot be stopped
© 2011 The McGraw-Hill Companies, Inc.
Synapses and
Neurotransmitters
Synapse/Synaptic Gap

space between sending axon’s terminal buttons and
the receiving dendrite or cell body
Synaptic Transmission



electrical impulse is converted into a chemical signal
axon vesicle releases neurotransmitter into gap
dendrite receptor site detects neurotransmitter
© 2011 The McGraw-Hill Companies, Inc.
Synapses and
Neurotransmitters
© 2011 The McGraw-Hill Companies, Inc.
Neurotransmitters
Neurotransmitters carry information
across the synaptic gap to next neuron.
Acetylcholine




muscle actions, learning, memory
black widow venom ↑ Ach levels
botox (botulin) ↓ Ach levels
Alzheimer’s disease: ↓ Ach levels
GABA

anxiety: ↓ GABA levels
© 2011 The McGraw-Hill Companies, Inc.
Neurotransmitters
Glutamate



excitatory
learning & memory
involved in many psychological disorders
Norepinephrine



stress and mania: ↑ norepinephrine levels
depression: ↓ norepinephrine levels
regulates sleep states in conjunction with ACh
© 2011 The McGraw-Hill Companies, Inc.
Neurotransmitters
Dopamine





voluntary movement
reward anticipation
stimulant drugs: activate dopamine receptors
Parkinson’s disease: ↓ dopamine levels
schizophrenia: ↑ dopamine levels
© 2011 The McGraw-Hill Companies, Inc.
Neurotransmitters
Serotonin



regulation of sleep, mood, attention, learning
depression: ↓ serotonin levels
prozac: ↑ serotonin levels
Endorphins


natural opiates
mediate feelings of pleasure and pain
© 2011 The McGraw-Hill Companies, Inc.
Neurotransmitters
Oxytocin



both a hormone and a neurotransmitter
related to onset of lactation in new mothers
related to attachment/emotional bonds
Note: Drugs can interfere with neurotransmitters
 mimics or enhances NT effects
 blocks effects of NT
© 2011 The McGraw-Hill Companies, Inc.
Neural Networks

interconnected pathways of nerve cells

integrate sensory input and motor output

take years to develop

a given piece of information embedded in
multiple connections between neurons
© 2011 The McGraw-Hill Companies, Inc.
Studying the Brain
Brain Lesioning

naturally occurring or induced
Electrical Recording


electroencephalograph (EEG)
single-unit recording
© 2011 The McGraw-Hill Companies, Inc.
Brain Imaging






X-Ray
CT Scan
PET
MRI
fMRI
TMS
© 2011 The McGraw-Hill Companies, Inc.
Hindbrain

Brainstem



medulla – control breathing, regulate reflexes
pons – sleep & arousal
Cerebellum

motor coordination
© 2011 The McGraw-Hill Companies, Inc.
Midbrain

Substantia Nigra


Parkinson disease
Reticular Formation

stereotyped behavior patterns like walking
© 2011 The McGraw-Hill Companies, Inc.
Brain: Structure and Function
© 2011 The McGraw-Hill Companies, Inc.
Forebrain

Limbic System


memory and emotion
amygdala
- discrimination of objects needed for survival
- emotional awareness and expression

hippocampus
- formation and recall of memories

Thalamus

relay station for much sensory information
© 2011 The McGraw-Hill Companies, Inc.
Forebrain (cont’d)

Basal Ganglia


coordination of voluntary movements
Hypothalamus



eating, drinking, sexual behaviors
regulate body’s internal state
emotion, stress, reward
© 2011 The McGraw-Hill Companies, Inc.
The Brain in Different Species
What brain structures are similar
across species?
How is the brain suited to each species?
© 2011 The McGraw-Hill Companies, Inc.
Cerebral Cortex
Neocortex: outermost layer
Four Lobes:




occipital (vision)
temporal (hearing, language processing, memory)
frontal (intelligence, personality, voluntary muscles)
parietal (spatial location, attention, motor control)
© 2011 The McGraw-Hill Companies, Inc.
Cerebral Cortex
© 2011 The McGraw-Hill Companies, Inc.
Are Brains Wired to
Recognize Faces?
 prosopagnosia
 fusiform face area (FFA)
 FFA – specifically for
processing faces?
© 2011 The McGraw-Hill Companies, Inc.
Somatosensory, Motor, and
Association Cortex
Somatosensoy Cortex (in parietal lobe)

body sensations
Motor Cortex (in frontal lobe)

voluntary movements
Point-to-Point Mapping
Association Cortex (75% of cortex)

not sensory or motor, but associations between
© 2011 The McGraw-Hill Companies, Inc.
Split-Brain Research
Corpus Callosum
x
Large bundle of axons that connects
X the two hemispheres of the brain

W.J., the Split Brain Patient
© 2011 The McGraw-Hill Companies, Inc.
Hemispheres of the Cortex
Hemispheric Specialization of Function

left hemisphere
verbal processing, speech, grammar



Broca’s Area
Wernicke’s Area
right hemisphere
spatial perception, visual recognition, emotion
© 2011 The McGraw-Hill Companies, Inc.
Happy Brains?
Happiness: Prefrontal Lobe Asymmetry

positive emotional responses
more left prefrontal lobe activity

negative emotional responses
more right prefrontal lobe activity
Biofeedback
Mindfulness (Awareness) Meditation
© 2011 The McGraw-Hill Companies, Inc.
Endocrine System

set of glands that regulate the body by secreting
hormones into the bloodstream

hormones = chemical messages

relatively slow communication system

interconnected with the nervous system

pituitary, thyroid, parathyroid, adrenal glands,
pancreas, ovaries, testes
© 2011 The McGraw-Hill Companies, Inc.
Brain Damage and Plasticity
Recovery from brain damage depends on


age of the individual
extent of the damage
Repairing the damaged brain




collateral sprouting
substitution of function
neurogenesis
brain tissue grafts
© 2011 The McGraw-Hill Companies, Inc.
Genetics and Behavior

chromosomes, genes, and DNA

Human Genome Project

dominant-recessive genes principle

molecular genetics

selective breeding

behavior genetics and adoption studies
© 2011 The McGraw-Hill Companies, Inc.
Genes and the Environment
Genotype – genetic heritage
+ the effects of experience =
Phenotype – observable characteristics



environment alters how genetic traits develop
both physical & psychological characteristics
genetic expression
© 2011 The McGraw-Hill Companies, Inc.
Biological Foundations and
Health and Wellness

stressors
…circumstances and events that threaten
individuals and/or tax their coping abilities

stress
…our response to those stressors

causes/effects of acute and chronic stress
© 2011 The McGraw-Hill Companies, Inc.
Chapter Summary




Discuss the nature and basic function of the
nervous system.
Explain what neurons are and how they process
information.
Identify the brain’s levels and structures and
summarize the function of those structures.
Identify the endocrine system and describe how
it affects behavior.
© 2011 The McGraw-Hill Companies, Inc.
Chapter Summary



Describe the brain’s capacity for recovery and
repair.
Explain how genetics increases understanding
of behavior.
Describe the role of the biological
foundations of human psychology in the
body’s stress response.
© 2011 The McGraw-Hill Companies, Inc.
Chapter Summary
The Nervous System




structure and function of the nervous systems
structure of a neruon
electrochemical communication
neurotransmitters and their effects
Brain: Structure and Function



brain imaging techniques
hindbrain, midbrain, forebrain
cerebral lobes and functions
© 2011 The McGraw-Hill Companies, Inc.
Chapter Summary
Brain Damage and Plasticity

collateral sprouting, substitution of function,
neurogenesis, brain tissue grafts
Genetics and Behavior

“genes v. environment” and adoption studies
Biological Foundations & Health and Wellness

acute and chronic stress
© 2011 The McGraw-Hill Companies, Inc.