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Chapter 3Biological Foundations of Behavior

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The Nervous System Brain: Structure and Function Brain Damage and Plasticity Genetics, Evolution, and Behavior Application: Health and Wellness

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The Nervous System

Neuroscience and Neuroscientists

Characteristics of the nervous system: Complexity Integration Adaptability Electrochemical transmission

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The Nervous System: Pathways

Afferent Nerves Carry information spinal cord and brain

Efferent Nerves Carry information muscles

Reflex Arc: Afferent nerve Interneuron Efferent nerve

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The Nervous System: Divisions

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The Nervous System: Divisions

Central nervous system (CNS) Brain and spinal cord

Peripheral nervous system (PNS) Somatic nervous system

Sensory nerves and muscular activity Autonomic nervous system – internal organs

Sympathetic nervous system – arouses Parasympathetic nervous system – calms

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Neurons: Structure

Brain: Approximately 100 billion neurons Glial Cells: Provide support and nutrition Specialized Cell Structure

Cell body Dendrites Axon Myelin sheath

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Neurons: Structure

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The Neural Impulse

Resting Potential Stable, negative charge of an inactive neuron

Action Potential Ion gates cause depolarization Brief, positive electrical charge: firing

All-or-None Principle Once initiated, it cannot be stopped

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Synapses and Neurotransmitters

Synaptic Transmission Neurochemical communication Action potential (electrical impulse) is

converted into a chemical signal Synapses

Space between terminal buttons and the receiving neuron’s cell body or dendrites

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Synapses and Neurotransmitters

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Neurotransmitters

Neurotransmitters either excite or inhibit Acetylcholine

Muscle actions, learning, memory Alzheimer’s disease: ↓ Ach levels Nicotine: ↑ Ach levels

GABA – inhibitory functions Anxiety: ↓ GABA levels

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Neurotransmitters

Norepinephrine Stress and mania: ↑ Norepinephrine levels Depression: ↓ Norepinephrine levels Regulates sleep states in conjunction with ACh

Dopamine Stimulant drugs: ↑ Dopamine levels Parkinson’s disease: ↓ Dopamine levels

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Neurotransmitters

Serotonin Regulation of sleep, mood, attention, learning Depression: ↓ Serotonin levels Prozac ↑ Serotonin levels

Endorphins Endogenous (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

Drugs and Neurotransmitters Agonist – mimics or enhances NT effects Antagonist – blocks effects of NT

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Studying the Brain

Lesioning Naturally occurring or induced

Staining Electrical Recording

Electroencephalogram (EEG) Single-unit recording Brain damage, sleep, epilepsy, happiness

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Brain Imaging

X-Ray CT Scan PET MRI fMRI

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Brain: Structure and Function

Hindbrain, Midbrain, and Forebrain Hindbrain

Medulla – control breathing, regulate reflexes Cerebellum – movement, coordination Pons – sleep, arousal

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Brain: Structure and Function

Midbrain Reticular Formation

Stereotyped behavior patterns like walking Brain Stem

Alertness, breathing, heart rate, blood pressure

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Brain: Structure and Function

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Brain: Structure and Function

Forebrain (continued next slide) Limbic System – memory and emotion

Amygdala Emotional awareness and expression

Hippocampus Formation and storage of memories

Thalamus Relay station for much sensory information

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Brain: Structure and Function

Forebrain (continued) Basal Ganglia

Coordination of voluntary movements Hypothalamus

Eating, drinking, sexual behaviors Emotion, stress, reward

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Cerebral Cortex

Occipital Lobe – Vision Temporal Lobe – Hearing, language

processing, memory Frontal Lobe – Intelligence, personality,

voluntary muscles Parietal Lobe - Spatial location, attention,

motor control

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Cerebral Cortex

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Somatosensory and Motor Cortex

Somatosensoy Cortex Located in the parietal lobe Processes info about body sensations

Motor Cortex Located in the frontal lobe Processes info about voluntary movements

Point-to-point Mapping

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Somatosensory and Motor Cortex

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Split-Brain Research

Corpus Callosum Large bundle of axons that connects the two

hemispheres of the brain Hemispheric Specialization of Function

Right hemisphere Spatial perception, visual recognition, emotion

Left hemisphere Verbal processing, speech, grammar

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Split-Brain Research

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Intersection: Happy Brains?

Happiness: Prefrontal Lobe Asymmetry Positive emotional responses

More left prefrontal lobe activity Negative emotional responses

More right prefrontal lobe activity

Caution: Correlational Research Mindfulness (Awareness) Meditation

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The Endocrine System

Set of glands that regulate the flow or hormones into the bloodstream

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 implants

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Genetics and Behavior

Chromosomes, DNA, and Genes The Dominant-Recessive Genes Principle The Human Genome Project Behavior Genetics and Adoption Studies

Fraternal and identical twins

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Genes and the Environment

The “Nature versus Nurture” Debate Nature describes one’s genetic potential

Genotype – genetic heritage Nurture the expression of that potential

Phenotype – observable characteristics Both physical and psychological characteristics

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Application: Health and Wellness

Stressors – circumstances and events that threaten individuals and/or tax their coping abilities

Stress – our response to those stressors Effects of acute and chronic stress Cognitive restructuring and self-talk

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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.

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Chapter Summary

Identify the endocrine system and describe how it affects behavior.

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 implants Genetics, Evolution, and Behavior

“Nature versus Nurture” and adoption studies Application: Health and Wellness

Stress and self-talk