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Psychology in the News: Stem Cells: New Hope for Damaged Brains?
Research suggests that stem cells can be obtained from adult bone marrow, making the repair and replacement of damaged neurons more feasible
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The medulla is at the very bottom of the brain and top of the spinal column. It controls life-sustaining functions such as breathing and swallowing. The nerves from each side of the body also cross over in this structure to opposite sides
The pons is above the medulla and acts as a bridge between the lower part of the brain and the upper part. It influences sleep, dreaming, arousal, and coordination of movement on the left and right sides of the body
The reticular formation runs through the medulla and the pons and controls our wakefulness and arousal
The cerebellum is found at the base and back of the brain and coordinates fine, rapid motor movement, learned reflexes, posture, and muscle tone
The thalamus is the relay station that sends sensory information to the proper areas of the cortex
The hypothalamus controls hunger, thirst, sleep, sexual behavior, sleeping and waking, and emotions. It also controls the pituitary gland. The limbic system consists of the thalamus, hypothalamus, hippocampus, amygdala, and the fornix
The hippocampus is the part of the brain responsible for storing memories and remembering the locations of objects
The amygdala controls our fear responses and memory of fearful stimuli
The cortex is the outer covering of the cerebrum and consists of a tightly packed layer of neurons about one-tenth of an inch in thickness. Its wrinkles, or corticalization, allow for the greater cortical area and are associated with greater intelligence
The cortex is divided into two cerebral hemispheres connected by a thick band of neural fibers called the callosum corpus
The occipital lobes at the back and base of each hemisphere process vision and contain the primary visual cortex
The parietal lobes at the top and back of the cortex contain the somatosensory area, which processes our sense of touch, temperature, and body position. Taste is also processed in this lobe
The temporal lobes contain the primary auditory area and are also involved in understanding language
The frontal lobes contain the motor cortex, which controls the voluntary muscles, and are also where all the higher mental functions occur, such as planning, language, and complex decision making
Association areas of the cortex are found in all the lobes but particularly in the frontal lobes. These areas help people make sense of the information they receive from the lower areas of the brain
An area called Broca's area in the left frontal lobe is responsible for producing fluent, understandable speech. If damaged, the person has Broca's aphasia in which words will be halting and pronounced incorrectly
An area called Wernicke's area in the left temporal lobe is responsible for the understanding of language. If damaged, the person has Wernicke's aphasia in which speech is fluent but nonsensical. The wrong words are used
Classic Studies in Psychology: Through the Looking Glass: Spatial Neglect Spatial
Neglect comes from damage to the association areas on one side of the cortex, usually the right side. A person with this condition will ignore information from the opposite side of the body or the opposite visual field
Studies with split-brain patients, in which the corpus callosum has been severed to correct epilepsy, reveal that the left side of the brain seems to control language, writing, logical thought, analysis, and mathematical abilities. The left side also processes information sequentially
The right side of the brain processes information globally and controls emotional expression, spatial perception, recognition of faces, patterns, melodies, and emotions
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Examples of Absolute Thresholds
Sense | Thresholds | |
---|---|---|
Sight | A candle flame at 30 miles on a clear, dark night | |
Hearing | The tick of a watch 20 feet away in a quiet room | |
Smell | One drop of perfume diffused throughout a three-room apartment | |
Taste | 1 teaspoon of sugar in 2 gallons of water | |
Touch | A bee's wing falling on the cheek from 1 centimeter above |
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Pinna: the visible part of the ear
Auditory canal: a short tunnel that runs from the pinna to the eardrum
Visual accommodation: the change in the thickness of the lens as the eye focuses on objects that are far away or close
Rods: visual sensory receptors found at the back of the retina, responsible for noncolor sensitivity to low
Levels of light cones: visual sensory receptors found at the back of the retina, responsible for color vision and sharpness of vision
Blind spot: area in the retina where the axons of the three layers of retinal cells exit the eye to form the optic nerve, insensitive to light
Light adaptation: the recovery of the eye's sensitivity to visual stimuli in light after exposure to darkness
Trichromatic theory: theory of color vision that proposes three types of cones: 10 red, blue, and green
Afterimages: images that occur when a visual sensation persists for a brief time even after the original stimulus is removed
Opponent-process theory: theory of color vision that proposes four primary colors with cones arranged in pairs: red and green, blue and yellow
Dark adaptation: the recovery of the eye's sensitivity to visual stimuli in darkness after exposure to bright lights
Hertz ( Hz ): cycles or waves per second , a measurement of frequency
Habituation: tendency of the brain to stop attending to constant, unchanging information sensory
Adaptation: tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging
Olfaction (olfactory sense): the sensation of smell
Gustation: the sensation of a taste
Pitch: psychological experience of sound that corresponds to the frequency of the sound waves; higher frequencies are perceived as higher pitches
Place theory: theory of pitch that states that different pitches are experienced by the stimulation of hair cells in different locations on the organ of Corti
Frequency theory: theory of pitch that states that pitch is related to the speed of vibrations in the basilar membrane
Volley principle: theory of pitch that states that frequencies from about 400 Hz to 4000 Hz cause the hair cells ( auditory neurons ) to fire in a volley pattern, or take turns in firing
Olfactory bulbs: areas of the brain located just above the sinus cavity and just below the frontal lobes that receive information from the olfactory receptor cells
Somesthetic senses: the body senses consisting of the skin senses, the kinesthetic sense, and the vestibular senses
Skin senses: the sensations of touch, pressure, temperature, and pain
Kinesthetic sense: sense of the location of body parts in relation to the ground and each other
Vestibular senses: the sensations of movement, balance, and body position
Sensory conflict theory: an explanation of motion sickness in which the information from the eyes conflicts with the information from the vestibular senses, resulting in dizziness, nausea, and other physical discomfort
Cochlea: snail-shaped structure of the inner ear that is filled with fluid
Auditory nerve: bundle of axons from the hair cells in the inner ear
Perception: the method by which the sensations experienced at any given moment are interpreted and organized in some meaningful fashion
Müller-Lyer Illusion: illusion of line length that is distorted by inward - turning or outward- turning corners on the ends of the lines, causing lines of equal length to appear to be different.
Convergence: the rotation of the two eyes in their sockets to focus on a single object, resulting in greater convergence for closer objects and lesser convergence if objects are distant
Binocular disparity: the difference in images between the two eyes, which is greater for objects that are close and smaller for distant objects
Parapsychology: the study of ESP , ghosts, and other subjects that do not normally fall into the realm of ordinary psychology
Perceptual set (perceptual expectancy): the tendency to perceive things a certain way because previous experiences or expectations influence those perceptions
Top-down processing: the use of pre-existing knowledge to organize individual features into a unified whole
Bottom-up processing: the analysis of the smaller features to build up to a complete perception
Size constancy: the tendency to interpret an object as always being the same actual size, regardless of its distance
Shape constancy: the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina
Brightness constancy: the tendency to perceive the apparent brightness of an object as the same even when the light conditions change
Texture gradient: the tendency for textured surfaces to appear to become smaller and finer as distance from the viewer increases
Motion parallax: the perception of motion of objects in which close objects appear to move more quickly than objects that are farther away
Accommodation: as a monocular clue, the brain's use of information about the changing thickness of the lens of the eye in response to looking at objects that are close or far away
Continuity: the tendency to perceive things as simply as possible with a continuous pattern rather than with a complex, broken-up pattern
Contiguity: the tendency to perceive two things that happen close together in time as being related
Depth perception: the ability to perceive the world in three dimensions
Monocular cues (pictorial depth cues): cues for perceiving depth based on one eye only -binocular cues: cues for perceiving depth based on both eyes -Linear perspective: the tendency for parallel lines to appear to converge on each other
Relative size: perception that occurs when objects that a person expects to be of a certain size appears to be small and are, therefore, assumed to be much farther away
Overlap (interposition): the assumption that an object that appears to be blocking part of another object is in front of the second object and closer to the viewer
Aerial perspective: the haziness that surrounds objects that are farther away from the viewer, causing the distance to be perceived as greater
Figure-ground: the tendency to perceive objects, or figures, as existing on a background
Reversible figures: visual illusions in which the figure and ground can be reversed
Proximity: the tendency to perceive objects that are close to each other as part of the same grouping
Similarity: the tendency to perceive things that look similar to each other as being part of the same group
Closure: the tendency to complete figures that are incomplete
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