Memory & Cognition (ch. 1-4) - Midterm 1

Hyperpolarization

An increase in the negative charge inside a neuron, making firing less likely

Depolarization

A reduction in negative charge that moves a neuron toward firing

Repolarization

Return of a neuron to a more positive resting state after firing

Action potential

A rapid electrical signal that travels down an axon when threshold is reached

All-or-none law

An action potential always occurs at full strength or not at all

Rate coding

Stronger stimuli produce higher frequencies of action potentials

Pattern coding (distributed representation)

Information is encoded by patterns of activity across many neurons

Cornea

The curved, transparent outer surface of the eye that first bends incoming light

Aqueous humor

Clear fluid filling the space between cornea and pupil

Iris

The colored muscle structure that controls pupil size

Pupil

The opening that allows light to enter the eye

Lens

A transparent structure that focuses light onto the retina

Vitreous humor

Gel-like substance filling the space between lens and retina

Retina

The inner layer of the eye that converts light into neural signals

Fovea

Area of the retina with the sharpest visual focus

Optic nerve

Bundle of axons carrying visual signals to the brain

Accommodation

The lens changing shape to focus on near or far objects

Rods

Photoreceptors sensitive to low light, not color, mostly in the periphery

Cones

Photoreceptors responsible for color vision and high acuity, concentrated in the fovea

Color blindness

Reduced ability to distinguish colors due to cone sensitivity overlap

Bipolar cells

Retinal cells that transmit signals from photoreceptors to ganglion cells

Ganglion cells

Retinal output neurons whose axons form the optic nerve

Optic chiasm

The crossing point where some optic nerve fibers switch sides

Lateral geniculate nucleus (LGN)

Thalamic relay station for visual information

Primary visual cortex (V1)

Occipital lobe region that processes basic visual features

Emmetropia

Normal 20/20 vision

Myopia

Nearsightedness; distant objects appear blurry

Hyperopia

Farsightedness; near objects appear blurry

Presbyopia

Age-related loss of lens flexibility and focusing ability

Astigmatism

Distorted vision due to uneven curvature of the eye

Cataracts

Clouding of the lens that reduces transparency

Lateral inhibition

Activated visual cells suppress neighboring cells to enhance contrast

Edge enhancement

Perception of borders as darker to improve shape detection

Receptive field

The area of sensory space that influences a neuron’s firing

Visual field

The total area visible to the eyes

Orientation detector

A neuron that responds best to lines at a specific angle

Parallel processing

The brain analyzing multiple aspects of a stimulus simultaneously

Ventral pathway

The “what” visual stream involved in object identification

Dorsal pathway

The “where/how” visual stream involved in location and movement

Agnosia

Inability to recognize objects despite intact vision

Binding problem

The challenge of combining separately processed features into one perception

Neural synchrony

Simultaneous firing that helps link features of the same object

Perceptual set

Expectations shaped by experience that influence perception

Perceptual constancy

Perceiving stable object properties despite changing sensory input

Size constancy

Perceiving an object as the same size despite distance changes

Shape constancy

Perceiving an object’s shape as stable despite angle changes

Accommodation (depth cue)

Eye focusing adjustment that signals distance

Convergence

Eyes turning inward to focus on nearby objects

Divergence

Eyes turning outward to focus on distant objects

Binocular disparity

Differences between the two eyes’ images used for depth perception

Binocular overlap

The shared visual field seen by both eyes

Monocular cues

Depth information available from one eye

Motion parallax

Nearby objects appearing to move faster than distant ones

Optic flow

Global visual motion pattern as an observer moves

Associative agnosia

Inability to link visual input to stored knowledge despite intact perception

Apperceptive agnosia

Inability to organize visual features into a complete object

Feature detection

Identifying basic visual elements like lines, curves, and angles

Feature detector

A neural mechanism tuned to respond to specific visual features

Word frequency effect

Common words are recognized more easily than rare words

Word-superiority effect

Letters are recognized more accurately within words than alone

Feature net

A network of detectors representing features and their relationships

Detector activation

The level of readiness of a detector to respond

Threshold

Activation level required for a detector to fire

Bigram

A pair of letters

McClelland and Rumelhart model

Interactive activation model using excitatory and inhibitory connections

Recognition-by-components (RBC) model

Theory that objects are recognized by basic 3D shapes

Geon

A basic geometric component used to build object representations

Object model

A mental representation of a recognized object

Memory

The ability to encode, store, and retrieve information based on past experiences

Cognition

Mental processes involved in acquiring knowledge, including thinking, reasoning, and problem solving

Introspection

The method of examining and reporting one’s own conscious thoughts and experiences

Behaviorism

An approach that focuses on observable behavior and how it changes in response to stimuli, rewards, and punishments

Cognitive Psychology

An approach that bridges introspection and behaviorism

Cognitive Processes

Active, knowledge-based mental operations used to interpret information

Top-Down Processing

Perception guided by prior knowledge, expectations, and experience

Bottom-Up Processing

Perception driven by incoming sensory information

Inference

Reasoning backward from observations to infer hidden mental mechanisms

Empiricism

The view that knowledge comes from sensory experience and observation

Scientific Empiricism

The use of systematic observation and experimentation to study cognition

Cognitive Revolution

A shift in psychology emphasizing internal mental processes, influenced by computer science, language, and perception research

Accuracy

The correctness of a response or performance

Response Time (RT)

The speed at which an individual responds to a stimulus

Errors

Mistakes made during cognitive tasks

Neuroimaging Techniques

Brain-imaging methods used to study structure and function

Language

An infinitely generative system allowing the creation of novel sentences

Gestalt Perception

The idea that the whole is perceived as greater than the sum of its parts

Neural Basis of Cognition

The brain structures and neural systems underlying cognitive processes

Cognitive Appraisal

The recognition and identification of objects or faces

Emotional Appraisal

The emotional response associated with recognizing stimuli, amygdala

Prosopagnosia (Face Blindness)

The inability to recognize faces due to damage to the fusiform face area

Fusiform Face Area

A brain region specialized for face recognition

Capgras Syndrome

A disorder in which familiar people are recognized but perceived as impostors

Amygdala

A brain structure involved in emotional processing, fear, anxiety, and emotional memory

Prefrontal Cortex

A brain region involved in decision making, emotional regulation, and cognition

Primary Motor Cortex

The cortical area responsible for controlling voluntary muscle movements

Contralateral Control

The principle that each brain hemisphere controls the opposite side of the body

Association Areas

Cortical regions involved in integrating information across sensory and motor systems

Apraxia

Difficulty initiating or organizing voluntary movements

Agnosia

Difficulty recognizing familiar objects or stimuli despite intact sensory function

Unilateral Neglect Syndrome

A disorder in which one side of the visual field (typically the left) is ignored