Unit 1: Biological Bases of Behavior

INTERACTION OF HEREDITY AND ENVIRONMENT

Explain the relationship between heredity and environment in shaping behavior and mental processes.

• Heredity and environmental factors interact to shape behavior and mental processes.

• The evolutionary perspective explores how natural selection affects expression of behavior and mental processes to increase survival and reproductive success. Some theorists have sought to apply principles of the evolutionary perspective in ways that discriminate against others (eugenics).

• Research on the effects of genes on individual behavior and mental processes is often conducted using twin studies, family studies, and adoption studies.

Key Terms: Heredity, Nature v. Nurture, Eugenics, Mirco-genetics, Epigenetics, Heritability, Twin Studies

OVERVIEW OF THE NERVOUS SYSTEM

Differentiate among the subsystems of the human nervous system and their functions.

• The central nervous system includes the brain and the spinal cord and interacts with all processes in the body.

• The peripheral nervous system relays messages from the central nervous system to the rest of the body and includes the autonomic and somatic nervous systems.

Key Terms: Central Nervous System, Peripheral Nervous System, Autonomic Nervous System, Somatic Nervous System, Sympathetic Nervous system (Fight or Flight), Parasympathetic Nervous System (Rest and Digest)

THE NEURON AND NEURAL FIRING

Explain how the structures and functions of typical neurons in the central nervous system affect behavior and mental processes.

• Two common types of neural cells in the brain are neurons (neural cells that transmit information) and glial cells (cells that provide structure, insulation, communication, and waste transport). These types of cells form the basis of the nervous system and are the building blocks of all behavior and mental processes

• In the spinal cord, the reflex arc demonstrates how neurons within the central and peripheral nervous systems work together to respond to stimuli. Three types of neurons work together in the spinal cord to create a reflex arc: sensory neurons, motor neurons, and interneurons.

Explain how the basic process of neural transmission is related to behavior and mental processes.

• Each neurotransmitter has specific function(s) related to behavior and mental processes, which may depend on the neurotransmitter’s location in the nervous system. Neurotransmitters generally communicate either excitatory (making an action potential more likely) or inhibitory (making an action potential less likely) messages. Neurotransmitters related to behavior and mental processes for study in AP Psychology are limited to dopamine, serotonin, norepinephrine, glutamate, GABA,

• Outside of the nervous system, hormones perform actions similar to neurotransmitters. Hormones related to behavior and mental processes for study in AP Psychology are limited to adrenaline, leptin, ghrelin, melatonin, and oxytocin

Explain how psychoactive drugs affect behavior and mental processes.

• Psychoactive drugs can influence neurotransmitter function in various ways throughout the neural communication process. Some act as agonists which encourage neural firing. Some act as antagonists which discourage neural firing. Some act as reuptake inhibitors which block the reabsorption of neurotransmitters back into the cell.

• Psychoactive drugs have psychological and physiological effects.

• Psychoactive drug use can lead to tolerance and/or addiction. Addiction can create significant withdrawal symptoms if the psychoactive drugs are no longer consumed.

Key Terms: Neural Cells v. Glial Cells, Relex Arc, Sensory Neuron, Motor Neuron, Interneurons, Parts of the Neuron: Dendrites v. Axon Terminal (Synaptic end), Axon, All-or-Nothing principle, Depolarization, refractory period, Reuptake, Action Potential, Threshold, Excitatory v Inhibitory, Dopamine, Serotonin, Norepinephrine, Glutamate, GABA, Endorphins, Substance P, Acetylcholine (ACH), Adrenaline, Leptin, Ghrelin, Melatonin, Oxytocin, Hormones v. Neurotransmitters, Antagonists v Agonists, Stimulants, Depressants, Hallucinogens, Opioids, Addiction, Withdrawal

THE BRAIN

Explain how the structures and functions of the brain apply to behavior and mental processes.

• The brain stem (including the medulla) generally controls basic functioning such as breathing and heart rate.

• The reticular activating system and the brain’s reward center generally control some voluntary movement, eye movement, and some types of learning, cognition, and emotion.

• The cerebellum generally controls coordination of muscle movement, balance, and some forms of procedural learning.

• The cerebral cortex is divided into two hemispheres and includes the limbic system (thalamus, hypothalamus, pituitary gland, hippocampus, amygdala), corpus callosum, and the lobes of the cortex.

• Split brain research, achieved by severing the corpus callosum (often a treatment for severe epilepsy), reveals that the right and left hemispheres of the brain may specialize in different activities and functions.

• Brain plasticity is the ability of the brain to rewire itself or modify or create new connections throughout development and generally allows for the function of a damaged part of the brain to be assumed by a different part of the brain

• Research on the brain is done using scans (including EEG and fMRI), case studies, and surgical procedures (such as lesioning) to promote understanding of how the different structures of the brain work and how the brain functions together as a whole.

Key Terms: Brain Stem, Medulla, RAS, Cerebellum, Cerebral Cortex, Limbic System, Thalamus, Hypothalamus, Pituitary Gland, Hippocampus, Amygdala, Copus Callosum, Split Brain, Left V Right Hemisphere of brain, Contralateral, Frontal Lobes, Parietal Lobes, Temporal Lobes, Occipital Lobes, Wernicke’s Area, Broca’s Area, Aphasia, Brain plasticity, EEG, fMRI

Sleep

Explain how the sleep/wake cycle affects behavior and mental processes throughout the day and night.

• Consciousness has varying levels of awareness of thoughts, feelings, behavior, and events in individuals’ internal and external worlds. Sleep and wakefulness are two types of consciousness.

• The sleep/wake cycle is a circadian rhythm, which in humans is about a 24-hour cycle. Jet lag and shift work are disruptions of the circadian rhythm.

• The stages of sleep are identified by their specific EEG patterns.

• Theories regarding the structure and function of dreams include activation-synthesis and consolidation theory.

• Memory consolidation and restoration are current theories about why sleep occurs. These theories suggest that sleep is useful for organizing and consolidating memories or restoring depleted resources used throughout a given day

• Many disorders interrupt healthy sleep, and their effects on waking behavior and health vary. Sleep disruptions can affect physical and cognitive performance during wakefulness. Treating sleep disorders and following regular schedules for sleeping can improve waking performance and overall well-being. Disorders commonly studied in introductory psychology include insomnia, narcolepsy, REM sleep behavior disorder, sleep apnea, and somnambulism

Key Terms: Levels of Consciousness, Circadian Rhythm, NREM Stages, Hypnogogic, REM, REM Rebound, Activation- Synthesis Theory and Consolidation Theory. Neural Pruning, Sleep Disorders, Insomnia, narcolepsy, REM Sleep Behavior Disorder, Sleep Apnea, Somnambulism

Sensation

Explain how the process of sensation is related to behavior and mental processes.

• Sensation is the process of detecting information from the environment that meets a certain threshold and transducing stimuli into neurochemical messages for processing (perception) in the brain. The absolute threshold occurs when a stimulus can be detected at least 50% of the time.

• Detection of change in stimuli or diminished sensitivity to stimuli can be explained by the just noticeable difference and sensory adaptation. Weber’s law describes the degree to which stimuli need to be different for the difference to be detected.

• The sensory systems constantly work together in a process called sensory interaction. Synesthesia is an experience of sensation in which one system of sensation is experienced through another.

Explain how the structures and functions of the visual sensory system relate to behavior and mental processes.

• The retina is the photosensitive surface at the back of the eye. Cells in the retina capture visual information that is transduced to the brain for processing. Evidence of incomplete images captured by the retina is demonstrated by the presence of the blind spot, where the visual nerve exits the eye. The brain fills in the gaps in the incomplete retinal images to perceive a relatively complete picture of the world.

• Visual stimuli are focused onto the retina by the lens via a process called accommodation. When this process is altered, nearsightedness or farsightedness can result.

• Cells that lie in the periphery of the eye and detect shapes and movement, but not color, are called rods. These cells are mainly activated in low-light environments. These cells play a role in light and dark adaptation.

• Color vision is explained by both the trichromatic theory and the opponent-process theory.

• Damage to parts of the brain responsible for vision (mainly the occipital lobes) can result in disorders such as prosopagnosia (face blindness) and blindsight.

Explain how the structures and functions of the auditory sensory system relate to behavior and mental processes.

• Sound occurs through the movement of air molecules at different wavelengths (called pitch) and amplitudes (called loudness).

• Theories that help explain pitch perception include place theory, volley theory, and frequency theory.

• Sound localization describes how we identify where sounds in our environment are coming from.

• Hearing difficulties can result from aging and various kinds of damage to auditory structures. Types of hearing loss include conduction deafness and sensorineural deafness.

Explain how the structures and functions of the chemical sensory systems relate to behavior and mental processes.

• Structures in the nose and brain process and/ or transduce olfactory stimuli. Smell is the only sense not processed first in the thalamus of the brain. Pheromones produce chemical messages for the olfactory system.

• Gustation is the sense of taste, and types of tastes include sweet, sour, salty, bitter, umami, and oleogustus

• Structures in the tongue, mouth, and brain process and/or transduce basic tastes. The number of taste receptors on the tongue is related to how sensitive people are to tastes, classifying them as supertasters, medium tasters, or nontasters.

• The chemical senses interact to create the sensation of taste. Without the sense of smell, taste sensations are either muted or not experienced.

Explain how the structures and functions of the touch sensory system relate to behavior and mental processes.

• Structures within the skin and brain process and/or transduce touch stimuli. The sensation of “hot” is produced by the activation of warm and cold receptors in the skin.

Explain how the structures and functions of the pain sensory system relate to behavior and mental processes.

• Pain is processed both in the body and in the brain. Gate control theory is one attempt to describe the complexities of pain. Phantom limb sensation occurs when people who have lost limbs report sensation or pain where the limb used to be.

Explain how the structures and functions that maintain balance (vestibular) and body movement (kinesthetic) relate to behavior and mental processes.

• The vestibular sense controls balance and is primarily detected by the semicircular canals and structures in the brain.

• Kinesthesis is the sense of one’s body movement. Kinesthesis allows the body to move in coordinated ways without having to look at the various parts of the body as it moves.

Key Terms: Sensation v. Perception, Absolute Threshold, JND, Sensory adaptation, Weber’s Law, Synesthesia, Eye Structure: Lens, Retina, Iris, Pupil, Cornea, Optic Nerve, Ganglion Cells Transduction, Blind spot, Photoreceptors, Rods v. cones, Accommodation, Nearsighted v Farsighted, Trichromatic Theory v Opponent-Process Theory, Blue v Green v. Red Cones, Afterimages, Dichromatism, monochromatism, Prosopagnosia, Blindsight, Wavelength v Amplitude, Place Theory, Volley Theory, Frequency Theory, Sound Localization, Conduction Deafness, Sensorineural Deafness, Parts of the Ear, Inner, Outer, Middle Ear, Tympanic Membrane, Cochlea, Hair Cells, Olfactory Bulb, Transduction of nose, Gustation, Structures of the Toungue, Taste receptors, Chemical Senses, Transduction of touch, Warm v. cold receptors, Gate Control Theory, Phantom Limb, Vestibular v Kinesthetic, semi-circular canals, proprioception