Copyright © Allyn & Bacon 2007 Chapter 3 Biopsychology and the Foundations of Neuroscience

What is Biopsychology? Biopsychology: The specialty in psychology that studies the interaction of biology, behavior, and mental processes Biopsychology: The specialty in psychology that studies the interaction of biology, behavior, and mental processes Neuroscience: Interdisciplinary field that focuses on the brain and its role in psychological processes Neuroscience: Interdisciplinary field that focuses on the brain and its role in psychological processes

Evolution has fundamentally shaped psychological processes because it favors genetic variations that produce adaptive behavior. How Are Genes and Behavior Linked?

Innate: Inborn; present at birth; part of the organism’s biological heritage Innate: Inborn; present at birth; part of the organism’s biological heritage Evolution: The gradual process of biological change that occurs in a species as it adapts to its environment Evolution: The gradual process of biological change that occurs in a species as it adapts to its environment

Evolution and Natural Selection Natural selection: The driving force behind evolution, by which the environment “selects” the fittest organisms Natural selection: The driving force behind evolution, by which the environment “selects” the fittest organisms

How Natural Selection Works Environmental pressure (changes in the environment) Competition (for resources) Selection of fittest phenotype (from among a variety of phenotypes) Reproductive success (genotype corresponding to fittest phenotypes passed to next generation) Frequency of that genotype increases (in next generation)

Genes and Inheritance Genotype: An organism’s genetic makeup Genotype: An organism’s genetic makeup Phenotype: An organism’s observable physical characteristics Phenotype: An organism’s observable physical characteristics Mutations: Genetic variations, which occur randomly, especially during the recombination of chromosomes in sexual reproduction Mutations: Genetic variations, which occur randomly, especially during the recombination of chromosomes in sexual reproduction

Chromosomes, Genes, and DNA DNA: A long, complex molecule that encodes genetic characteristics DNA: A long, complex molecule that encodes genetic characteristics Genes: The functional units of a chromosome Genes: The functional units of a chromosome Composed of nucleotides Composed of nucleotides Chromosomes: Tightly coiled threadlike structures along which the genes are organized Chromosomes: Tightly coiled threadlike structures along which the genes are organized Sex chromosomes: The X and Y chromosomes that determine our physical sex characteristics Genes influence our psychological characteristics as well as our physical traits Genes influence our psychological characteristics as well as our physical traits

The body’s two communication systems, the nervous system and the endocrine system, both use chemical messengers to communicate with targets throughout the body How Does the Body Communicate Internally?

The Neuron Types of Neurons (specialized cell that responds to and sends signals) Types of Neurons (specialized cell that responds to and sends signals) Sensory neurons: carry messages from sense receptors towards the CNS (afferent – approach CNS)Sensory neurons: carry messages from sense receptors towards the CNS (afferent – approach CNS) Motor neurons: carry messages from CNS toward muscles and glands (efferent – exit CNS) Interneurons: carry messages between nerve cells

The Structure of a Neuron

The Neural Impulse Resting potential: Electrical charge of a neuron when it is ready to fire; it’s inactive state (-70mv) Resting potential: Electrical charge of a neuron when it is ready to fire; it’s inactive state (-70mv) (+) potassium inside; (+) sodium outside; sodium wants in! (+) potassium inside; (+) sodium outside; sodium wants in! Action potential: Nerve impulse caused by a reversal in the electrical charge across the axon (- to +) Action potential: Nerve impulse caused by a reversal in the electrical charge across the axon (- to +) Depolarization: sodium gates open; let sodium (+) in Depolarization: sodium gates open; let sodium (+) in Repolarization: sodium gates close, potassium gates open and let potassium (+) out; potassium gates close when charge is leveled (back to -) Repolarization: sodium gates close, potassium gates open and let potassium (+) out; potassium gates close when charge is leveled (back to -) Refractory period: time period in which the neuron cannot reach its action potential; repolarizing to return to its resting potential (polarized) Refractory period: time period in which the neuron cannot reach its action potential; repolarizing to return to its resting potential (polarized)

The Neural Impulse All-or-none principle: Action potential occurs full blown or not at all; must cross threshold (minimum level of stimulation needed) All-or-none principle: Action potential occurs full blown or not at all; must cross threshold (minimum level of stimulation needed) Impulses only move in one direction!!! Impulses only move in one direction!!! Synapse: Gap that serves as a communication link between neurons Synapse: Gap that serves as a communication link between neurons b/w terminal buttons of one neuron and dendrites of another neuron b/w terminal buttons of one neuron and dendrites of another neuron Synaptic transmission: relaying of info across the synapse by means of neurotransmitters Synaptic transmission: relaying of info across the synapse by means of neurotransmitters

Plasticity and Glial Cells Plasticity: Ability of the nervous system to adapt or change as the result of experience Plasticity: Ability of the nervous system to adapt or change as the result of experience Sometimes helps the nervous system adapt to physical damage Sometimes helps the nervous system adapt to physical damage Neurons make new connections Neurons make new connections Example - sprout new dendrites Example - sprout new dendrites Glial cells Glial cells Provide structural support for neurons Provide structural support for neurons Help in forming new synapses Help in forming new synapses Form myelin sheath Form myelin sheath Cleans up dead cells Cleans up dead cells

Neurotransmitters Neurotransmitters: Chemical messengers that relay neural messages across the synapse Neurotransmitters: Chemical messengers that relay neural messages across the synapse Diffuse across synapse & connect like lock and key Diffuse across synapse & connect like lock and key Agonist: drug/chemical that enhances or mimics the effects of NTs – facilitates messages; turns up volume Agonist: drug/chemical that enhances or mimics the effects of NTs – facilitates messages; turns up volume Antagonist: drug/chemical that inhibits the effects of NTs – blocks receptor sites; turns down volume Antagonist: drug/chemical that inhibits the effects of NTs – blocks receptor sites; turns down volume Reuptake: recycling of NT back into the pre- synaptic neuron Reuptake: recycling of NT back into the pre- synaptic neuron Turns message volume down Turns message volume down SSRI – inhibits reuptake, so turns SSRI – inhibits reuptake, so turns up volume of serotonin

Reuptake in the Synapse

NeurotransmittersDopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Produces sensations of pleasure and reward; used by CNS neurons in voluntary movement Problems with Imbalance: Schizophrenia, Parkinson’s disease Substances that Affect: Cocaine, amphetamines, Ritalin, alcohol

Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Regulates sleep and dreaming, mood, pain, aggression, appetite and sexual behavior Problems with Imbalance: Depression, certain anxiety disorders, obsessive- compulsive disorder Substances that Affect: Prozac, hallucinogenics (e.g. LSD) Neurotransmitters

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Controls heart rate, sleep, sexual responsiveness, stress, vigilance and appetite Problems with Imbalance: High blood pressure, depression Substances that Affect: Tricyclic antidepressants, beta blockers

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Primary transmitter used by neurons carrying messages from CNS; involved in some kinds of learning and memory Problems with Imbalance: Certain muscular disorders, Alzheimer’s disease Substances that Affect: Nicotine, botulism toxin, curare, atropine

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Most prevalent inhibitory neurotransmitter in neurons of CNS Problems with Imbalance: Anxiety, epilepsy Substances that Affect: Barbiturates, tranquilizers (e.g. Valium, Librium), alcohol

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Primary excitatory neurotransmitter in CNS; involved in learning and memory Problems with Imbalance: Brain damage after stroke Substances that Affect: PCP (“angel dust”)

Neurotransmitters Dopamine Serotonin Acetylcholine Glutamine Norepinephrine GABA Endorphins Normal Function: Pleasurable sensations and control of pain Problems with Imbalance: Lowered levels resulting from opiate addiction Substances that Affect: Opiates: opium, heroin, morphine, methadone

The Organization of the Nervous System Nervous system Peripheral nervous system Central nervous system (CNS) Autonomic nervous system Somatic nervous system Sympathetic nervous system Parasympathetic nervous system

The Endocrine System The body’s chemical messenger system The body’s chemical messenger system

The Endocrine System Pituitary gland : Pituitary gland : Master gland Master gland Produces hormones influencing the secretions of all other endocrine glands Produces hormones influencing the secretions of all other endocrine glands Produces hormone that influences growth Produces hormone that influences growth Attached to hypothalamus Attached to hypothalamus

How Does the Brain Produce Behavior and Mental Processes? The brain is composed of many specialized modules that work together to create mind and behavior.

Windows on the Brain Brain waves: Patterns of electrical activity generated by the brain Brain waves: Patterns of electrical activity generated by the brain EEG (electroencephalograph): Records brain waves; electrodes placed on scalp EEG (electroencephalograph): Records brain waves; electrodes placed on scalp

Windows on the Brain Brain scans: Recordings of the brain’s electrical or biochemical activity at specific sites Brain scans: Recordings of the brain’s electrical or biochemical activity at specific sites CAT/CT (computerized tomography) – soft tissue, structure, x-ray CAT/CT (computerized tomography) – soft tissue, structure, x-ray PET (positron emission tomography) – activity, not structure, detects glucose in active circuits PET (positron emission tomography) – activity, not structure, detects glucose in active circuits fMRI (magnetic resonance imaging) – moving pic. of brain in action fMRI (magnetic resonance imaging) – moving pic. of brain in action

The Four Lobes of the Cerebral Cortex Frontal lobes (AKA pre-frontal cortex): planning, deciding, thinking, motor cortex, personality? Frontal lobes (AKA pre-frontal cortex): planning, deciding, thinking, motor cortex, personality? Parietal lobes: touch sensation, spatial relationships, somatosensory cortex Occipital lobes: contain visual cortex Temporal lobes: sounds, including speech, auditory cortex

Three Layers of the Brain Brain stem structures, cerebellum, and thalamus Brain stem structures, cerebellum, and thalamus Drive vital functions, such as heart rate, breathing, digestion Drive vital functions, such as heart rate, breathing, digestion Limbic system Limbic system Adds emotions, complex motives, increased memory abilities Adds emotions, complex motives, increased memory abilities Cerebrum Cerebrum Enables reasoning, planning, creating, problem solving Enables reasoning, planning, creating, problem solving

The Cerebrum Cerebrum : Topmost layer of the brain; the bulbous cap over the limbic system Cerebrum : Topmost layer of the brain; the bulbous cap over the limbic system Cerebral cortex : Thin gray-matter covering of the cerebrum; carries on thinking and perceiving (higher-order processes) Cerebral cortex : Thin gray-matter covering of the cerebrum; carries on thinking and perceiving (higher-order processes) Cerebral hemispheres : The two walnut shaped halves of the cerebrum, connected by the corpus callosum Cerebral hemispheres : The two walnut shaped halves of the cerebrum, connected by the corpus callosum

Important Areas Thalamus Thalamus Pons Pons Cerebellum Cerebellum Medulla Medulla Brain stem Brain stem Reticular Reticular Formation Formation

The Limbic System Hypothalamus – Serves as the brain’s blood- testing laboratory, constantly monitors blood to determine the condition of the body Hypothalamus – Serves as the brain’s blood- testing laboratory, constantly monitors blood to determine the condition of the body

The Limbic System Amygdala – Involved in memory and emotion, particularly fear and aggression Amygdala – Involved in memory and emotion, particularly fear and aggression

The Limbic System Hippocampus – Involved in establishing long-term memories Hippocampus – Involved in establishing long-term memories

Aphasia The impairment of language (speech or understanding) The impairment of language (speech or understanding) Broca’s Area – interferes w/ speech production (frontal lobe damage) Broca’s Area – interferes w/ speech production (frontal lobe damage) can understand language can understand language words not properly formed words not properly formed speech is slow and slurred speech is slow and slurred some aware of deficits some aware of deficits Wernicke’s Area – loss of ability to understand language (parietal/temporal) Wernicke’s Area – loss of ability to understand language (parietal/temporal) can speak clearly most of the time can speak clearly most of the time words put together make no sense; word salads words put together make no sense; word salads not aware of deficits not aware of deficits

The Cooperative Brain Association cortex: Cortical regions that combine information from various other parts of the brain Association cortex: Cortical regions that combine information from various other parts of the brain Cerebral dominance: Tendency of each brain hemisphere to exert control over different functions Cerebral dominance: Tendency of each brain hemisphere to exert control over different functions

Specialization of the Cerebral Hemispheres Left Hemisphere Right Hemisphere Spontaneous speaking and writing Responses to complex commands Word rec./ speech Memory for words and numbers Sequences of movements Feelings of anxiety Positive emotion Repetitive but not spontaneous speaking Responses to simple commands Facial recognition Memory for shapes and music Spatial interpretation Emotional responsiveness Negative emotion

The Split Brain Split-brain patients: Individuals who have had the corpus callosum surgically severed Split-brain patients: Individuals who have had the corpus callosum surgically severed Duality of consciousness: Condition in which a split- brain patient has a separate consciousness in each hemisphere Duality of consciousness: Condition in which a split- brain patient has a separate consciousness in each hemisphere