Biological Bases of Behavior Notes
Rapid Review: Biological Bases of Behavior
Neuropsychology
Neuropsychologists study the relationship between the brain/nervous system and behavior.
Also called biological psychologists, biopsychologists, behavioral geneticists, physiological psychologists, and behavioral neuroscientists.
Brain damage studies link loss of structure with loss of function.
Lesions: Destruction of brain tissue for studying loss of function.
Brain Imaging Techniques
Structure:
CT scans (Computerized Axial Tomography): Use X-rays to create computerized images.
MRI (Magnetic Resonance Imaging): Uses magnetic fields and radio waves for detailed images.
Function:
EEG (Electroencephalogram): Measures brain activity with electrodes; Evoked potentials are EEGs in response to specific stimuli.
PET (Positron Emission Tomography): Tracks radioactively tagged glucose to show brain activity.
fMRI (Functional MRI): Measures brain activity through changes in oxygen concentration.
Nervous System
Central Nervous System (CNS): Brain and spinal cord.
Peripheral Nervous System (PNS): All nerves outside the brain and spinal cord.
Autonomic Nervous System (ANS): Motor nerves to smooth and heart muscle.
Sympathetic: "Fight or flight" responses.
Parasympathetic: Returns body to resting state.
Somatic Nervous System: Motor nerves to skeletal muscles.
Brain Structure
Spinal cord: Below the medulla.
Brain: Above the spinal cord.
Evolutionary Model:
Reptilian brain: Medulla, pons, cerebellum.
Old mammalian brain: Limbic system, hypothalamus, thalamus.
New mammalian brain: Cerebral cortex.
Developmental Model:
Hindbrain: Medulla, pons, cerebellum.
Midbrain: Eye reflexes and movements.
Forebrain: Limbic system, hypothalamus, thalamus, cerebral cortex.
Convolutions: Folds in the cerebral cortex increasing surface area.
Contralaterality: Each brain side controls the opposite body side.
Brain Parts and Functions
Medulla oblongata: Regulates heart rhythm, blood flow, breathing, digestion, vomiting.
Pons: Contains reticular formation for arousal and wakefulness; relays information.
Cerebellum: Controls posture, balance, and movement.
Basal ganglia: Regulates movement initiation, balance, eye movements, and implicit memories.
Thalamus: Relays sensory information to/from cerebral cortex.
Hypothalamus: Controls feeding, drinking, temperature, sexual behavior, rage, and hormone secretion.
Amygdala: Influences emotions like aggression and fear.
Hippocampus: Enables new long-term memory formation.
Cerebral cortex: Higher-order processes, sensory information, and movement.
Association areas: Higher mental functions (thinking, planning, communicating).
Cerebral Cortex Lobes
Occipital lobes: Visual information.
Parietal lobes: Somatosensory cortex (touch, temperature, pain); object perception.
Frontal lobes: Emotional behaviors, decisions, plans, motor cortex (movement), speech (Broca's area).
Temporal lobes: Hearing, language (Wernicke's area), music, smell.
Neurons and Neurotransmitters
Neuron: Basic unit of the nervous system.
Cell body (soma/cyton): Contains nucleus.
Dendrites: Receive information.
Axon: Transmits action potential.
Myelin sheath: Speeds up conduction.
Terminal buttons: Secrete neurotransmitters.
Neurotransmitters: Chemical messengers.
Acetylcholine (ACh): Muscle contraction, memory; lack linked to Alzheimer's.
Dopamine: Alertness, attention, movement; Lack is linked to Parkinson's; excess is linked to schizophrenia.
Glutamate: Brain stimulation, memory, information processing.
Serotonin: Arousal, sleep, mood; Lack is linked to depression.
Endorphins: Pain relief and pleasure.
GABA (Gamma-aminobutyric acid): Inhibits neuron firing; malfunction linked to Huntington's and seizures.
Action Potential and Synapse
Action potential: "Firing" of a neuron, sodium ions flow in.
All-or-none principle: Neuron fires or doesn't, strength is constant.
Nodes of Ranvier: Spaces between myelin segments.
Saltatory conduction: Rapid impulse conduction in myelinated axons.
Synapse: Communication region between neurons.
Excitatory neurotransmitter: Causes action potential.
Inhibitory neurotransmitter: Reduces neural impulses.
Reflexes and Reflex Arc
Reflex: Simplest form of behavior.
Reflex arc: Path of a reflex.
Sensory receptor: Initiates action potentials.
Afferent neuron: Transmits impulses to CNS.
Interneuron: Between sensory and motor neurons in CNS.
Efferent neuron: Transmits impulses to muscles or glands.
Effector: Muscle or gland.
Endocrine System
Ductless glands secreting hormones into the blood.
Hormone: Chemical messenger to target organ.
Pineal gland: Melatonin, circadian rhythms.
Hypothalamus: Stimulates/inhibits pituitary.
Pituitary gland: Secretes stimulating hormones.
Thyroid gland: Thyroxine, metabolism.
Parathyroids: Calcium ion level.
Adrenal glands: Cortisol (stress), adrenaline, noradrenaline.
Pancreas: Insulin and glucagon, blood sugar.
Ovaries and testes: Sex hormones.
Genetics and Heredity
Evolutionary psychologists: Study behaviors that contributed to survival.
Behavioral geneticists: Study genes and environment in behavior.
Zygote: Fertilized egg.
Identical twins (monozygotic): Share all genes.
Fraternal twins (dizygotic): Share about half of genes.
Heritability: Genetic contribution to variation.
Adoption studies: Reveal environmental vs. heredity contributions.
Genes and Chromosomes
Gene: DNA segment determining a trait.
Chromosome: Contains genes.
Human cells: 23 pairs of chromosomes.
Sex chromosomes: Father's Y determines male sex.
Genetic Disorders
Turner syndrome: Females with one X chromosome.
Klinefelter's syndrome: Males with XXY chromosomes.
Down syndrome: Three copies of chromosome 21.
Genetic Terms
Genotype: Genetic makeup.
Phenotype: Expression of genes.
Homozygous: Same genes for a trait.
Heterozygous: Different genes for a trait.
Dominant gene: Expressed when genes differ.
Recessive gene: Hidden when genes differ.
Tay-Sachs syndrome: Recessive, nervous function loss.
Albinism: Recessive, lack of pigment.
Phenylketonuria (PKU): Recessive, brain damage if untreated.
Huntington's disease: Dominant, nervous system degeneration.
Sex-linked traits: Recessive on X chromosome, more common in males.
Color blindness: Sex-linked, inability to see certain colors.
Consciousness
Consciousness: Awareness of self and environment.
Levels of consciousness:
Normally conscious: Focused awareness.
Preconscious: Easily accessible feelings and memories.
Unconscious: Unacceptable feelings and thoughts.
Nonconscious: Inaccessible processes.
Dual processing: Conscious and unconscious levels.
Sleep and Circadian Rhythms
Hypothalamus: Controls biological clock.
Circadian rhythms: Daily patterns of changes.
Reticular formation: Regulates sleep, wakefulness, arousal, and attention.
States of consciousness: Waking, daydreaming, sleep, hypnosis, meditation, drug-induced states.
Sleep stages:
NREM-1: Drifting thoughts, theta waves.
NREM-2: Sleep spindles and K-complexes.
NREM-3: Deep sleep, delta waves, slowed heart rate, growth hormone.
REM: Dreaming, paralyzed muscles, EEG similar to wakefulness.
Sleep disorders: Insomnia, narcolepsy, sleep apnea.
Sleep disruptions: Night terrors, sleepwalking (somnambulism).
Theories of Dreams
Freudian: Safety valve for unconscious desires.
Manifest content: Remembered story line.
Latent content: Underlying meaning.
Activation-synthesis: Brainstem stimulates forebrain with random activity.
Cognitive information processing: Brain waves and psychological functioning.
Altered States of Consciousness
Daydreaming: Focus on inner realities.
Hypnosis: Deep relaxation and suggestibility.
Meditation: Focus away from thoughts for calmness.
Psychoactive Drugs
Psychoactive drug: Alters perception, thinking, behavior, and mood.
Categories:
Depressants: Reduce CNS activity.
Narcotics: Depress CNS, relieve pain.
Stimulants: Activate motivational centers.
Hallucinogens: Distort perceptions.
Psychological dependence: Intense desire for the drug.
Physiological dependence (addiction): Blood chemistry changes, withdrawal symptoms.
Withdrawal symptoms: Intense craving and opposite effects.