AP EXAM REVIEW #2 Biological bases of behavior, Sensation and Perception
1. Physiological Techniques (scans) • Lesioning – damage to the brain • EEG - An amplified recording of the waves of electrical activity that sweep across the brain’s surface; measured by electrodes placed on the scalp • PET Scan (Positron emission tomography)- A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task. • MRI (Magnetic Resonance Imaging) - A technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue, allowing us to see structures within the brain. • fMRI - A technique for revealing blood flow and therefore, brain activity by comparing successive MRI scans
2. Neuroanatomy – know the parts and functions Axon Terminals AXON Myelin Sheath Soma Axon Terminal Buttons Dendrites
Synapse - The junction between neurons.Synaptic gap, synaptic cleft, etcLess than a millionth of an inch wide Synapse
3. Neural Transmission • Resting Potential - the electrical charge of a neuron at rest. • Action Potential - A neural impulse in the form of a brief electrical charge that travels down the axon • A neuron fires an impulse when it receives a signal from sense receptors or by the neurotransmitters from another neuron. Direction of ACTION POTENTIAL
Neural Transmission cont. Neuron receives chemical message. • Axon’s ion channels (holes in the axon membrane) open, allowing Na+ ions inside. • Ion channels open like a domino effect, traveling from the soma to the axon terminal. • After the impulse passes, the neuron dips below resting potential and cannot fire. The “ion pump” flushes out positive ions as it releases K+ions outside. Less than 1/100 of a second. Resting and Action Potential
4. Neurotransmitters - chemical messengers that travel across the synaptic gap between neurons • Action potential reaches the axon’s terminal buttons. • Buttons release neurotransmitters (chemicals) • Travel across the synapse • Bind/connect to receptor sites on the next neuron’s dendrites • Agonist vs. Antagonist
5. Nervous System • Central Nervous System - The brain and the spinal cord • Peripheral Nervous System - the sensory and motor neurons that connect the CNS to the rest of the body. • Everything but the brain and spinal cord
Nervous System • Information travels through the nervous system in 3 type of neurons. • Sensory neurons – (aka afferent neurons) carry incoming information from the senses to the CNS • Interneurons– CNS neurons that internally communicate between sensory inputs and motor outputs • Motor Neurons – (aka efferent neurons) carry out going information from the CNS to muscles and glands Sensory feel… Inter interpret… Motor move S.A.M.E. – Sensory Afferent Motor Efferent
6. Somatic and Autonomic Nervous Systems • Somatic – controls the body’s skeletal muscles • Running, dancing, etc • Autonomic – controls the glands and the muscles of internal organs • Heartbeat, digestion, sweating • Sympathetic – arouses the body • Parasympathetic – calms the body • Parasympathetic - paralyzing
7. Endocrine System • The body’s “slow” chemical communication system made of glands that secrete hormones into the bloodstream • Hormones– chemical messengers manufactured by glands • Travel slowly in the bloodstream • When hormones act on the brain, they can trigger interest in sex, food, aggression, “flight or fight” • Gland- An organ in the body that secretes a substance for use somewhere else in the body
8. Parts of the Brain • Medulla • Pons • Reticular Formation • Cerebellum • Thalamus • Corpus Collosum • Limbic System • Hippocampus • Amygdala • Hypothalamus • Cerebral Cortex
9. Lobes of the Cerebral Cortex • Geographical subdivisions of the cerebral cortex separated by prominent fissures (folds) in the brain.
10. Association Areas • Sensory Cortex - An area at the front of the PARIETAL lobe that registers and processes body touch and movement sensations • Motor Cortex - An area at the rear of the FRONTAL lobe that controls voluntary movements • Visual Cortex – An area in the OCCIPITAL lobe that processes vision from the opposite eye • Auditory Cortex - An area in the TEMPORAL lobe that processes sounds from the opposite ear • Aphasia – impairment of language, usually caused by left hemisphere damage either to… • Broca’s area – frontal lobe, left hemisphere, directs movement necessary for speech • Wernicke’s area – temporal lobe, left hemisphere, involved in language comprehension • Plasticity
1. Attention • Selective Attention - The focusing of conscious awareness on a particular stimulus • You can only focus on a certain amount of stimulus at once… advantages and dangers of multitasking (cocktail party effect) • Inattention Blindness - Failing to see visible objects when our attention is directed elsewhere • Change Blindness • Change Deafness
2. Absolute Thresholds • Absolute Threshold - Weakest amount of stimulus required to produce a sensation 50% of the time
3. Signal Detection Theory • A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise) • assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and level of fatigue. • ex: exhausted parents of a newborn will hear the faintest whimper from the cradle while failing to notice louder, unimportant sounds.
4. Difference Threshold • AKA - Just Noticeable Difference (JND) • Minimum amount of difference a person can detect between two stimuli • Ex: the difference between similar colors, the difference in voices of children, the difference in wines, etc • Weber’s Law - The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage, rather than a constant amount. • Assumes there is no constant difference threshold • The saltier the soup, the harder it is to taste more salt; the louder the music the more you need to increase it to hear a difference
5. Vision • Parts and functions of the eye • Cornea, Iris, Pupil, Lens Vitreous Humor, Retina, Fovea, Blind Spot • Rods and Cones • Acuity • Feature Detectors - Nerve cells in the brain that respond to specific features of stimuli, such as shape, angle, or movement • Parallel Processing - The brain's natural mode of processing several things at once • Young-Hemholtz Trichromatic Theory - Theory that the retina contains three different color receptors - sensitive to red, green, and blue - when stimulated in different combinations can produce the perception of any color • Opponent Process Theory - The theory that opposing retinal processes (red-green, yellow-blue, and black-white) enable color vision
6. Hearing • Parts and functions of the eye • Ear Canal, Ear Drum, Osicles, Cochlea, Semicircular Canals, Auditory Nerve • Place Theory - Links the pitch we hear with the place where the cochlea’s membrane is stimulated • High pitch sounds • Frequency Theory - The rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch • Low pitch sounds • Conduction vs. Sensorineural Deafness
7. Other Senses • Somatosensation = Touch • 4 distinct skin senses – Pressure, Warmth, Cold, Pain • Only the sensation of pressure has specialized nerves in the skin; the rest of the nerve endings can feel warmth, cold, and pain in various combinations • Gate-Control Theory -The spinal cord acts as a gate that controls if pain signals reach the brain • Taste - 5 basic tastes • Sweet, Salty, Sour, Bitter, Umami • Taste buds (200+ per bump on tongue) catch food chemicals via receptor cells (Receptor cells more sensitive to different tastes) • Smell - Odors are composed of chemical molecules which are sensed by olfactory receptor cells at the top of the nasal cavity.
8. Gestalt Rules of Perception • Figure-Ground Relationship • Grouping -Proximity, Similarity, Continuity, Closure, Connectedness, Common fate • Binocular Cues - Depth cues that rely on the use of both eyes • Retinal disparity – a binocular cue for perceiving depth; the brain compare the images from the two eyeballs and computes the difference - the greater the disparity between images, the closer the object. • Convergence – a binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object – the greater the strain, the closer the object. • Monocular Cues - Depth cues that are available to each eye separately • Relative size, Interposition, Relative clarity, Texture gradient, Relative height, Relative motion, Linear perspective, Light and shadow
9. Perceptual Processes • Perceptual Constancy - the ability to perceive objects as unchanging even as illumination and retinal images change (we can identify things even if their color or angle change) • Perceptual Adaptation - In vision, the ability to adjust to an artificially displaced or even inverted visual field • When people are given glasses that distort the world, they are initially disoriented, but soon adapt to the new context and can navigate it with ease. • Perceptual Set - A mental predisposition to perceive one thing and not another. • Experiences, expectations, and assumption result in the formation of concepts/schemas to organize and interpret information which then dictate what we perceive
Nucleus Chromosome Gene Cell DNA 10. Genetics • Chromosomes – threadlike structures made of DNA that contain the genes • DNA (deoxyribonucleic acid) – a complex molecule containing the genetic information that makes up the chromosomes • Genes – the biochemical units of heredity that makes up the chromosomes • Synthesize and create protein molecules which become the building blocks of psychical development.
Genetics continued • Genome – the complete instructions for making an organism that consists of all the genetic material in the chromosomes • As humans we share 99.9% of the same DNA, but the 0.01% difference is what makes us all different. • Humans and chimpanzees share about 95% of the same DNA – close cousins, but clearly very different.