Exam Study Notes
Unit 1: The Biological Bases of Behavior
Communication in the Nervous System - Hardware
Glia:
Structural support and insulation for neurons.
Role in memory formation.
Involved in chronic pain.
Implicated in psychological disorders.
Neurons:
Responsible for communication within the nervous system.
Soma (cell body): Contains the cell's life-support center.
Dendrites: Receive messages from other cells.
Axon: Transmits messages away from the cell body.
Neuron Structure
Terminal branches of axon: Form junctions with other cells.
Cell body (Soma): The cell's life-support center.
Dendrites: Receive messages from other cells.
Axon: Passes messages away from the cell body to other neurons, muscles, or glands.
Neural impulse: Electrical signal traveling down the axon.
Myelin sheath: Covers the axon of some neurons; speeds up neural impulses.
Neural Communication: Insulation and Information Transfer
Myelin sheath: Speeds up transmission of neural signals.
Terminal button: The end of the axon; secretes neurotransmitters.
Neurotransmitters: Chemical messengers that transmit signals across synapses.
Synapse: The point at which neurons interconnect.
The Neural Impulse: Electrochemical Beginnings
Hodgkin & Huxley (1952): Pioneering research using giant squid axons.
Fluids inside and outside neuron contain electrically charged particles (ions).
Neuron at rest: Exhibits a negative charge on the inside compared to the outside.
Resting potential: -70 millivolts (-70 \text{ mV}) – the electrical potential of a neuron at rest.
The Neural Impulse: The Action Potential
Stimulation causes the cell membrane to open briefly.
Positively charged sodium ions flow into the cell.
Shift in electrical charge travels along the neuron, creating the action potential.
Action Potential:
All-or-none law: A neuron either fires completely or not at all.
Refractory Period: A period after firing when a neuron is unable to fire again immediately.
The Synapse: Chemicals as Signal Couriers
Synaptic cleft: The gap between the presynaptic and postsynaptic neurons.
Presynaptic neuron: The neuron sending the signal.
Synaptic vesicles: Sacs containing neurotransmitters.
Neurotransmitters: Chemical messengers.
Postsynaptic neuron: The neuron receiving the signal.
Receptor sites: Locations on the postsynaptic neuron where neurotransmitters bind.
When a Neurotransmitter Binds: The Postsynaptic Potential
Voltage change at receptor site: Postsynaptic potential (PSP).
Not all-or-none.
Changes the probability of the postsynaptic neuron firing.
Positive voltage shift: Excitatory PSP (EPSP) – increases the likelihood of firing.
Negative voltage shift: Inhibitory PSP (IPSP) – decreases the likelihood of firing.
Overview of Synaptic Transmission
Synthesis and storage of neurotransmitter molecules in synaptic vesicles.
Release of neurotransmitter molecules into the synaptic cleft.
Binding of neurotransmitters at receptor sites on the postsynaptic membrane.
Inactivation (by enzymes) or removal (drifting away) of neurotransmitters.
Reuptake of neurotransmitters sponged up by the presynaptic neuron.
Signals: From Postsynaptic Potentials to Neural Networks
One neuron receives signals from thousands of other neurons.
Requires integration: Combining and processing signals to produce an output signal.
PSPs add up and balance out.
Balance between IPSPs and EPSPs determines if a neuron will fire.
Neural networks:
Patterns of neural activity.
Interconnected neurons that fire together or sequentially.
Synaptic pruning: Elimination and creation of synaptic connections over time, influenced by experience.
Neurotransmitters
Specific neurotransmitters work at specific synapses.
Lock and key mechanism: Neurotransmitters bind to specific receptors.
Agonist: Mimics neurotransmitter action.
Antagonist: Opposes the action of a neurotransmitter.
15 – 20 neurotransmitters known at present.
Interactions between neurotransmitter circuits are complex and important for behavior.
Common Neurotransmitters and Their Relations to Behavior
Acetylcholine (ACh):
Released by motor neurons controlling skeletal muscles.
Contributes to the regulation of attention, arousal, and memory.
Some ACh receptors stimulated by nicotine.
Dysregulation associated with Alzheimer's disease.
Dopamine (DA):
Contributes to control of voluntary movement.
Cocaine and amphetamines elevate activity at DA synapses.
Dopamine circuits in medial forebrain bundle characterized as "reward pathway."
Dysregulation associated with Parkinsonism, schizophrenic disorders, and addictive disorders.
Norepinephrine (NE):
Contributes to modulation of mood and arousal.
Cocaine and amphetamines elevate activity at NE synapses.
Dysregulation associated with depressive disorders.
Serotonin:
Involved in regulation of sleep and wakefulness, eating, aggression.
Prozac and similar antidepressant drugs affect serotonin circuits.
Dysregulation associated with depressive disorders, obsessive-compulsive disorders, and eating disorders.
GABA:
Serves as a widely distributed inhibitory transmitter, contributing to regulation of anxiety and sleep/arousal.
Valium and similar antianxiety drugs work at GABA synapses.
Dysregulation associated with anxiety disorders.
Glutamate:
Serves as a widely distributed excitatory transmitter.
Involved in learning and memory.
Dysregulation associated with schizophrenia.
Endorphins:
Resemble opiate drugs in structure and effects.
Play role in pain relief and response to stress.
Contribute to regulation of eating behavior.
Organization of the Nervous System
Central nervous system (CNS): Brain and spinal cord.
Peripheral nervous system:
Somatic nervous system: Sensory (afferent) and motor (efferent) nerves.
Autonomic nervous system (ANS): Controls involuntary functions.
Sympathetic: Fight or flight response.
Parasympathetic: Rest and digest functions.
Afferent: Toward the CNS (arrive).
Efferent: Away from the CNS (exit).
Divisions of the Brain
Forebrain: Emotion, complex thought.
Thalamus, hypothalamus, limbic system, cerebrum, cerebral cortex.
Midbrain: Sensory functions.
Dopaminergic projections, reticular activating system.
Hindbrain: Vital functions.
Medulla, pons, and cerebellum.
The Cerebrum: Two Hemispheres, Four Lobes
Cerebral Hemispheres: Two specialized halves connected by the corpus callosum.
Left hemisphere: Verbal processing: language, speech, reading, writing.
Right hemisphere: Nonverbal processing: spatial, musical, visual recognition.
Four Lobes:
Occipital: Vision.
Parietal: Somatosensory (touch, temperature, pain).
Temporal: Auditory (hearing).
Frontal: Movement, executive control systems (planning, decision-making).
Brain Structures and Areas
Cerebrum: Responsible for sensing, thinking, learning, emotion, consciousness, and voluntary movement
Corpus callosum: Bridge of fibers passing information between two cerebral hemispheres
Thalamus: Relay center for cortex; handles incoming and outgoing signals
Hypothalamus: Responsible for regulating basic biological needs: hunger, thirst, temperature control
Pituitary gland: "Master" gland that regulates other endocrine glands
Hippocampus: Part of limbic system involved in learning and memory
Amygdala: Part of limbic system involved in emotion and aggression
Midbrain
Hindbrain
Pons: Involved in sleep and arousal
Medulla: Responsible for regulating largely unconscious functions such as breathing and circulation.
Spinal cord: Responsible for transmitting information between brain and rest of body; handles simple reflexes
Cerebellum: Structure that coordinates fine muscle movement, balance
Reticular formation: Group of fibers that carry stimulation related to sleep and arousal through brainstem
Cerebral Cortex
Primary visual cortex: Receives visual information (Occipital lobe).
Primary somatosensory cortex: Receives sensory information about touch, temperature, pain, and pressure (Parietal lobe).
Primary motor cortex: Controls voluntary movements (Frontal lobe).
Primary auditory cortex: Receives auditory information (Temporal lobe).
Prefrontal cortex: Involved in higher-level cognitive functions such as planning and decision-making (Frontal lobe).
Mirror Neurons
Discovered accidentally in the mid-1990s.
May play a role in the acquisition of new motor skills, imitation of others, the ability to feel empathy for others.
Dysfunctions in mirror neuron circuits may underlie the social deficits seen in autistic disorders.
The Plasticity of the Brain
The brain is more “plastic” or malleable than widely assumed.
Aspects of experience can sculpt features of brain structure.
Damage to incoming sensory pathways or tissue can lead to neural reorganization.
Adult brain can generate new neurons - neurogenesis.
Language Processing in the Brain
Broca's area: Involved in speech production.
Wernicke's area: Involved in language comprehension.
Aphasia: Language impairment caused by brain damage.
Broca's Aphasia: Difficulty producing speech.
Wernicke's Aphasia: Difficulty understanding language.
Studying the Brain: Research Methods
Electroencephalography (EEG):
Measures electrical activity in the brain.
Damage studies/lesioning:
Examining the effects of brain damage on behavior.
Electrical stimulation (ESB):
New technique used to treat chronic pain and tremors associated with Parkinson’s.
Transcranial magnetic stimulation (TMS):
Uses magnetic fields to stimulate nerve cells in the brain.
Brain imaging:
Computerized tomography (CT).
Positron emission tomography (PET).
Magnetic resonance imaging (MRI).
Functional magnetic resonance imaging (fMRI).
The Endocrine System: Glands & Hormones
Hormones: Chemical messengers in the bloodstream.
Pulsatile release by endocrine glands.
Negative feedback system: Maintains homeostasis (stability) in the body.
Endocrine glands:
Pituitary: “Master gland,” growth hormone.
Thyroid: Metabolic rate.
Adrenal: Salt and carbohydrate metabolism.
Pancreas: Sugar metabolism.
Gonads: Sex hormones.
Genes and Behavior: The Field of Behavioral Genetics
Behavioral genetics: The study of the influence of genetic factors on behavioral traits.
Chromosomes: Strands of DNA carrying genetic information.
Human cells contain 46 chromosomes in pairs (sex-cells – 23 single).
Each chromosome contains thousands of genes, also in pairs.
Dominant, recessive genes.
Homozygous, heterozygous.
Genotype/Phenotype and Polygenic Inheritance.
Research Methods in Behavioral Genetics
Family studies: Does it run in the family?
Twin studies: Compare resemblance of identical (monozygotic) and fraternal (dizygotic) twins on a trait.
Adoption studies: Examine resemblance between adopted children and their biological and adoptive parents.
Genetic Relatedness
Identical twins: 100%
First-degree relatives (parents, siblings, children): 50%
Second-degree relatives (grandparents, aunts/uncles, nieces/nephews, half-siblings): 25%
Third-degree relatives (first cousins): 12.5%
Modern Approaches to the Nature vs. Nurture Debate
Molecular Genetics: The study of the biochemical bases of genetic inheritance.
Genetic mapping: Locating specific genes
The Human Genome Project.
Behavioral Genetics.
The interactionist model: Emphasizes the interaction between genes and environment.
Richard Rose (2000) – “Genes confer dispositions, not destinies.”
Evolutionary Psychology: Behavior in Terms of Adaptive Significance
Based on Darwin’s ideas of natural selection.
Reproductive success is key.
Adaptations: Behavioral as well as physical.
Fight-or-flight response.
Taste preferences.
Parental investment and mating strategies.
AP PSYCHOLOGY - The Eye
The Eye
Iris
Lens
Pupil
Cornea
Retina
Blind spot
Fovea (point of central focus)
Optic nerve to brain's visual cortex
The Retina
Transduction: Process by which sensory cells in the eyes convert light into electrical signals that the brain can interpret
Receptors in the Human Eye
Rods:
Periphery of retina.
Function in low light conditions.
Detect black and white.
Cones:
Center of retina (fovea).
Function in well-lit conditions.
Detect color.
Receptor Density
Rods are more numerous than cones.
Cones are concentrated in the fovea.
The graph shows the distribution of rods and cones across the retina.
Visual Pathways
Visual information from the left visual field is processed in the right visual cortex, and vice versa.
Optic nerves from each eye cross at the optic chiasm.
Information travels through the thalamus (lateral geniculate nucleus) to the visual cortex.
Suprachiasmatic nucleus of hypothalamus
Lateral geniculate nucleus of thalamus
Left visual cortex
Right visual cortex
Visual Information Processing
Feature Detectors
Hubel and Wiesel (1979): Research on feature detectors in the visual cortex.
Specialized neurons that only respond to certain sensory information (shape, angle, movement).
Different parts of your primary visual cortex are responsible for identifying different things
Prosopagnosia
An impairment in the ability to perceive and recognize faces, whereas the ability to recognize other objects may be relatively unaffected. PROSOPAGNOSIA
Face Blindness part 1 (12:44)
Face Blindness part 2 (13:15)
AP PSYCHOLOGY - Theories of Color Vision
Physical Properties of Light Waves
Short wavelength = high frequency (bluish colors, high-pitched sounds)
Long wavelength = low frequency (reddish colors, low-pitched sounds)
Great amplitude (bright colors, loud sounds)
Small amplitude (dull colors, soft sounds)
Young-Helmholtz Trichromatic Theory
The eye has three types of color receptors (cones): red, green, and blue.
Color perception is based on the activity of these three receptors.
Opponent-Process Theory
Color vision is based on opposing pairs of colors: red/green, blue/yellow, black/white.
Activation of one member of the pair inhibits activity in the other.
Opponent Process Theory: afterimages
the opponent-process theory states that the cone photoreceptors are linked together to form three opposing color pairs: blue/yellow, red/green, and black/white. Activation of one member of the pair inhibits activity in the other. Afterimages
An afterimage is what you see if you stare at a visual stimulus for a while and then look at a blank white space.
Hearing - Audition
Audition: The sense or act of hearing.
Hearing loss can occur
occur due to:
The Ear
Outer Ear
Middle Ear
Inner Ear
Sound waves
Bones of the middle ear
Semicircular canals
Bone
Auditory nerve
Cochlea
Eardrum
Oval window
Auditory canal
(where stirrup attaches)
Degeneration of Hair Cells
Two bundles of aging outer hair cells showing severe degeneration. The outer hair cells are responsible for fine tuning and amplifying the sounds that are detected by the inner hair cells. This age-related degeneration of hair cells is responsible for the hearing loss often associated with aging.
The Ear - Structure
Outer Ear: Pinna. Collects sounds.
Middle Ear: Chamber between eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window.
Inner Ear: Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.
Theories of Audition: Helmholtz Place Theory
suggests that sound frequencies stimulate the basilar membrane at specific places resulting in perceived pitch.
Theories of Audition: Frequency Theory
Frequency Theory states that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.
Hearing Loss
Conduction Hearing Loss: Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.
Sensorineural Hearing Loss: Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve, also called nerve deafness.
Localization of Sounds
Because we have two ears, sounds that reach one ear faster than the other ear cause us to localize the sound.
Sensation and Perception
SENSATION
The process of detecting, converting, and transmitting raw sensory information from the external and internal environments to the brain
PERCEPTION
The process of selecting, organizing and interpreting sensory information
Process of Sensation
Light, sound, smell, taste, touch, etc
PROCESS TRANSDUCTION
Stimulus Energy
Sensory Receptors
Neural Impulses
Brain
Eyes, ears, nose, tongue, skin
Visual, auditory, olfactory areas, etc.
THE Sensation Perception
Information Processing
TOP-DOWN PROCESSING
Information processing guided by higher- level mental processes, as when we construct perceptions drawing on our experience and expectations.
BOTTOM-UP PROCESSING
Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.
AP Psychology - Thresholds
Absolute Threshold
Subliminal Stimuli
Absolute Threshold: Examples
the minimum stimulus energy needed to detect a particular stimulus 50% of the time (Approximate)
Just Noticeable Difference
A candle flame at 30 miles on a dark, clear night.
A ticking clock at 20 feet under quiet conditions.
One drop of perfume diffused throughout three rooms.
A teaspoon of sugar in 2 gallons of water.
The wing of a fly falling on your neck from a distance of 1 centimeter.
Weber's Law
2 stimuli must differ by a constant proportion to be perceived as different
JND = KI (Just Noticeable Difference)= (Original Intensity)
BRIGHTNESS- 1.7\%%
WEIGHT- 2\%%
PITCH- 0.3\%%
ODOR- 5\%%
SALTINESS OF TASTE- 20\%%
We add 1 candle to 20 candles and we notice. We add 1 to 120 and we don’t. We add 6 to 120…
Signal Detection Theory
Hit
Miss
False Alarm
Correct Rejection
Responds yes
Responds no
Signal present
Signal absent
Sensory Adaptation
Constant stimuli
Biological
AP PSYCHOLOGY - BODILY & CHEMICAL SENSES
Bodily Senses
Touch
Tactile sense
Pressure, pain, cold, warmth
Nociceptors
Somatosensory cortex
Pain
Gate Control Theory
Non-painful sensory input can dampen or block painful sensations from reaching the brain
Phantom Limb
The perception of feeling in an appendage even after an it has been removed from the body
KINESTHETIC SENSE
enables control and coordination over movements, including walking, talking, facial expressions, gestures, and posture (Proprioception)
VESTIBULAR SENSE
enables the maintenance of balance in part controlled by the semicircular canals, which contains receptors that detect motions of the head
Body Position & Movement
Chemical Senses
Smell
NASAL CAVITY
OLFACTORY BULB
CONNECTION TO TASTE
Taste
CHEMICAL SENSE
SWEET
SALTY
SOUR
BITTER
UMAMI
RECEPTOR CELLS
SUPERTASTERS
Sensory Interaction
One sense influences another
Embodied Cognition
Bodily sensation influences cognitive processes