Chapter 2 Biopsychology

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

How Are Genes and Behavior Linked? 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 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

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 Phenotype – An organism’s observable physical characteristics

Genes and Inheritance 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 Genes – The functional units of a chromosome Composed of nucleotides

Chromosomes, Genes, and DNA Chromosomes – Tightly coiled threadlike structures along which the genes are organized Sex chromosomes – The X and Y chromosomes that determine our physical sex characteristics

Genetic Explanations for Psychological Processes Genes influence our psychological characteristics as well as our physical traits

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

The Neuron Types of Neurons Sensory neurons (carry messages from sense receptors towards the CNS) Motor neurons (carry messages from CNS toward muscles and glands) Interneurons (carry messages between nerve cells)

The Structure of a Neuron

The Neural Impulse Neural impulse – Brief electric surge that carries the neuron’s message Ions – Charged particles that are moved across the cell membrane

The Neural Impulse Resting potential Action potential Synapse Synaptic transmission

Neurotransmitters Neurotransmitters – Chemical messengers that relay neural messages across the synapse

Seven Important Neurotransmitters Dopamine Serotonin Norepinephrine Acetylcholine GABA Glutamine Endorphins

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

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

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

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

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

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

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

Plasticity Plasticity – Ability of the nervous system to adapt or change as the result of experience; sometimes helps the nervous system adapt to physical damage

Glial Cells Glial cells Provide structural support for neurons Help in forming new synapses Form myelin sheath

The Organization of the 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 Endocrine System Pituitary gland – Master gland that produces hormones influencing the secretions of all other endocrine glands; produces hormone that influences growth; 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 EEG (electroencephalograph) – Device for recording brain waves, typically by electrodes placed on the scalp Brain waves – Patterns of electrical activity generated by the brain

Windows on the Brain Epilepsy – Brain disorder that is often marked by seizures and loss of consciousness; caused by out-of-control electrical activity in the brain

Windows on the Brain Lesions – Tissue damage that results from disease or injury

Windows on the Brain Brain scans – Recordings of the brain’s electrical or biochemical activity at specific sites CT scanning (computerized tomography) PET scanning (positron emission tomography) MRI (magnetic resonance imaging)

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

The Brain Stem and Cerebellum Thalamus Pons Cerebellum Medulla Brain stem

The Limbic System 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

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

The Cerebrum 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 Cerebral hemispheres – The two walnut shaped halves of the cerebrum, connected by the corpus callosum

The Four Lobes of the Cerebral Cortex Frontal lobes (movement and thinking) Parietal lobes (touch sensation and spatial relationships) Occipital lobes (contain visual cortex) Temporal lobes (process sounds, including speech)

The Cooperative Brain Association cortex – Cortical regions that combine information from various other parts of the brain

Cerebral Dominance Cerebral dominance – Tendency of each brain hemisphere to exert control over different functions Aphasia – The loss of speech caused be brain damage Spatial orientation – Process of locating one’s body or other objects in space

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

The Split Brain 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

Copyright © Allyn and Bacon 2006 End of Chapter 2 Copyright © Allyn and Bacon 2006