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Chapter 3Biological Foundations of Behavior

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Nervous System Neurons Brain Endocrine System Damage, Plasticity, and Repair Genetics and Behavior Biological Foundations and Health and Wellness

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Nervous System

Neuroscience…study of the body’s electrochemical communication circuitry

Characteristics of the nervous system complexity integration adaptability (plasticity) electrochemical transmission

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Nervous System: Pathways

Afferent Nervescarry information spinal cord and brain

Efferent Nervescarry information muscles

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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

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Nervous System: Divisions

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Nervous System - Cells

Neurons information processing about 100 billion in brain mirror neurons (in primates)

Glial Cells provide support and nutrition

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Neurons: Structure

cell body

dendrites

axon

myelin sheath

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Neurons: Structure

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Neural Impulse

Axons ions/ion channel negatively/positively charged semipermeable membrane polarization

Resting Potential stable charge of an inactive neuron

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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

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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

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Synapses and Neurotransmitters

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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

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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

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Neurotransmitters

Dopamine

voluntary movement reward anticipation stimulant drugs: activate dopamine receptors Parkinson’s disease: ↓ dopamine levels schizophrenia: ↑ dopamine levels

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Neurotransmitters

Serotonin regulation of sleep, mood, attention, learning depression: ↓ serotonin levels prozac: ↑ serotonin levels

Endorphins natural opiates mediate feelings of pleasure and pain

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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

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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

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Studying the Brain

Brain Lesioning naturally occurring or induced

Electrical Recording electroencephalograph (EEG) single-unit recording

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Brain Imaging

X-Ray CT Scan PET MRI fMRI TMS

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Hindbrain

Brainstem medulla – control breathing, regulate reflexes pons – sleep & arousal

Cerebellum motor coordination

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Midbrain

Substantia Nigra Parkinson disease

Reticular Formation stereotyped behavior patterns like walking

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Brain: Structure and Function

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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

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Forebrain (cont’d)

Basal Ganglia coordination of voluntary movements

Hypothalamus eating, drinking, sexual behaviors regulate body’s internal state emotion, stress, reward

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The Brain in Different Species

What brain structures are similar What brain structures are similar

across species?across species?

How is the brain suited to each speciesHow is the brain suited to each species??

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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)

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Cerebral Cortex

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Are Brains Wired to Recognize Faces?

prosopagnosia

fusiform face area (FFA)

FFA – specifically for processing faces?

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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

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Split-Brain Research

x

X

Corpus Callosum

Large bundle of axons that connects the two hemispheres of the brain

W.J., the Split Brain Patient

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Hemispheres of the Cortex

Hemispheric Specialization of Function

left hemisphereverbal processing, speech, grammar

Broca’s Area Wernicke’s Area

right hemispherespatial perception, visual recognition, emotion

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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

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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

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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

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Genetics and Behavior

chromosomes, genes, and DNA

Human Genome Project

dominant-recessive genes principle

molecular genetics

selective breeding

behavior genetics and adoption studies

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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

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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

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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.

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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.

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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

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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