S&P Exam 1

An electrochemical signal that begins in the dendrites of a neuron and travels down the axon to the axon terminals.

The minimum intensity of a physical stimulus that can just be detected by an observer.

The assumption that the functional organization of human cognition and of the brain is essentially the same in everyone.

A projection that emanates from the cell body of a neuron and that conducts neural signals to the axon terminals, for transmission to other neurons.

Endings of an axon, where neural signals are transmitted to other neurons.

A neuron's low rate of spontaneous firing at fairly random intervals in the absence of any stimulus.

The information contained in neural signals from receptors.

The part of a cell that contains the nucleus.

A cell structure that separates what's inside the cell from what's outside the cell.

The outermost layer of the cerebral hemispheres; about 2-4 mm thick and consisting mostly of gray matter (neural cell bodies).

The two most important divisions of the brain; separated by the longitudinal fissure.

The investigation of perceptual and cognitive deficits in individuals with brain damage in order to discover how perception and cognition are carried out in the normal, undamaged brain.

A large bundle of axons that constitutes the major connection between the two cerebral hemispheres.

In a signal detection experiment, a response indicating that no signal was detected on a trial when no signal was presented.

n signal detection theory, the difference between the mean of the curve showing the strength of perceptual evidence (e.g., the number of action potentials) when no signal is presented and the mean of the curve when a signal is presented; depends on the physical intensity of the signal and the participant's perceptual sensitivity, but not on the participant's decision criterion.

In a signal detection experiment, a participant's tendency to be liberal or conservative in deciding whether a signal was detected; indicated by the value of the participant's decision criterion.

Projections that emanate from the cell body of a neuron and that receive signals from other neurons.

Part of the sequence of events of an action potential, during which an inflow of positively charged ions causes the membrane potential to become markedly more positive.

The minimum difference between two stimuli that allows an observer to perceive that the two stimuli are different.

In cognitive neuropsychology, a pattern of brain damage and impaired function in which damage to some specific brain region is associated with impairment of some specific function but not with impairment of another function.

A perceived object or event in the world.

In cognitive neuropsychology, a pattern of brain damage and impaired function in which damage to some specific brain region is associated with impairment of some specific function A but not with impairment of another function B, along with a pattern (in a different patient) in which damage to a different region is associated with impairment of function B but not with impairment of function A.

A functional neuroimaging technique based on measurement of the electrical fields associated with brain activity.

Neurotransmitters that have an excitatory effect on the postsynaptic neuron, increasing the probability that an action potential will be initiated.

The effect of an excitatory neurotransmitter, making the postsynaptic neuron's membrane potential more positive.

In a signal detection experiment, a response indicating that a signal was detected on a trial when no signal was presented.

The rate at which a neuron produces action potentials; usually expressed in terms of spikes per second.

One of the four lobes of each cerebral hemisphere; separated from the temporal lobe by the lateral sulcus and from the parietal lobe by the central sulcus.

A functional neuroimaging technique based on measurement of the changes in blood oxygenation associated with brain activity.

An array of techniques for measuring brain activity in healthy volunteers carrying out carefully designed tasks.

The cell bodies of neurons making up the cerebral cortex.

An elongated bump on the surface of the cerebral hemispheres.

Neurotransmitters that have an inhibitory effect on the postsynaptic neuron, decreasing the probability that an action potential will be initiated.

The effect of an inhibitory neurotransmitter, making the postsynaptic neuron's membrane potential more negative.

An atom that has an imbalance in the number of protons and electrons and that therefore has an electric charge.

Small pores in the cell membrane of neurons through which certain ions can flow into or out of the cell.

A functional neuroimaging technique based on measurement of the magnetic fields associated with brain activity.

A difference in electrical potential across the cell membrane, due to a difference in the concentrations of positive and negative ions inside and outside the cell.

A behavioral method used in psychophysical experiments; the participant observes a stimulus and adjusts a knob that directly controls the intensity of the stimulus.

A behavioral method used in psychophysical experiments; the participant is presented with a fixed set of stimuli covering a range of intensities that are presented repeatedly in random order, and the participant must indicate whether or not each stimulus was detected.

The idea that the human mind and brain consist of a set of distinct modules, each of which carries out one or more specific functions.

A bundle of axons that travel together from one location in the nervous system to another.

A pattern of neural signals that carries information about a stimulus and can serve as a representation of that stimulus.

Information-carrying electrochemical signals produced and transmitted by neurons.

The principle that perception depends on the combined activity of many specialized neurons, each of which responds to specific aspects of a stimulus.

Cells of the nervous system that produce and transmit information-carrying signals.

Chemical substances involved in the transmission of signals between neurons; neurotransmitter molecules released into a synapse by the neuron sending a signal bind to receptors on the neuron receiving the signal.

In the study of neural activity, slight random variation in the number of action potentials produced by neurons in response to a fixed sensory stimulus.

One of the four lobes of each cerebral hemisphere; separated from the parietal lobe by the parieto-occipital sulcus.

One of the four lobes of each cerebral hemisphere; separated from the frontal lobe by the central sulcus, from the temporal lobe by the lateral sulcus, and from the occipital lobe by the parieto-occipital sulcus.

The later steps in the perceptual process, whereby the initial sensory signals are used to represent objects and events so they can be identified, stored in memory, and used in thought and action.

A functional neuroimaging technique based on measurement of the changes in blood flow associated with brain activity, using a radioactive substance introduced into the blood.

The membrane of the dendrite or cell body receiving a neural signal.

The membrane at the axon terminal of a neuron producing an action potential.

A physical phenomenon evoked by a distal stimulus that impinges on the specialized cells of a sense.

A curve that relates a measure of perceptual experience to the intensity of a physical stimulus.

The process of measuring how changes in stimulus intensity relate to changes in the perceived intensity.

A field of study concerned with relating psychological experience to physical stimuli.

In a signal detection experiment, a curve representing the quality of a participant's performance.

Following an action potential, a brief period during which a new action potential cannot be initiated.

Information in the mind and brain used to identify objects and events, to store them in memory, and to support thought and action.

The membrane potential when a neuron is at rest (about 270 mV).

The initial steps in the perceptual process, whereby physical features of the environment are converted into electrochemical signals that are sent to the brain for processing.

Physiological functions for converting particular environmental features into electrochemical signals.

Specialized neurons that convert proximal stimuli into neural signals.

A framework for measuring how people make decisions based on noisy perceptual evidence; provides a way to measure perceptual sensitivity apart from the decision-making style.

A technique used to measure the membrane potential.

A behavioral method used in psychophysical experiments; the participant is presented with a stimulus and indicates whether it was detected, and based on that response, the next stimulus is either one step up or one step down in intensity.

A statement of the relationship between the physical intensity of a stimulus and its perceived intensity (S = cIn, where S is the perceived intensity of the stimulus, I is its physical intensity, the exponent n is different for each perceptual dimension, and c is a constant that depends on which units are being used for S and I).

The objects and events that are perceived (distal stimuli) and the physical phenomena they produce (proximal stimuli).

An indentation between two gyri on the surface of the cerebral hemispheres.

A tiny gap between the axon terminal of one neuron and the dendrite or cell body of another neuron.

Within axon terminals, tiny sacs that contain neurotransmitter molecules.

One of the four lobes of each cerebral hemisphere; separated from the frontal lobe and the parietal lobe by the lateral sulcus.

The most important subcortical structure involved in perception; most neural signals pass through the thalamus on their paths from the sensory organs to the cortex.

An observer's knowledge, expectations, and goals, which can affect perception.

The transformation of a physical stimulus into neural signals.

In signal detection theory, a measure of the overall satisfaction resulting from a given decision.

The constant k in Weber's law (JND = kI).

A statement of the relationship between the intensity of a standard stimulus and the size of the just noticeable difference (JND = kI, where I is the intensity of the standard stimulus and k is a constant that depends on the perceptual dimension being measured).

The myelin-covered axons of cortical neurons, making up the interior parts of the cerebral hemispheres; these axons connect neurons located in different parts of the cerebral cortex.

Adjustment of the shape of the lens so light from objects at different distances focuses correctly on the retina.

A measure of how clearly fine detail is seen.

Neurons in the inner nuclear layer of the retina.

A condition in which both eyes develop normally but the neural signals from one eye aren't processed properly, so that fine vision doesn't develop in that eye.

The space between the cornea and the iris, filled with aqueous humor.

A clear, thin fluid filling the anterior and posterior chambers of the eye.

A condition in which the curvature of the cornea or lens is slightly irregular or asymmetrical, making it impossible for the lens to fully accommodate.

Neurons in the inner nuclear layer of the retina.

A progressive "clouding" of the lens that can, if left untreated, lead to blindness.

An RGC receptive field in which the center of the receptive field responds differently to stimulation than the surrounding portion of the field.

The middle membrane of the eye, lining the interior of the sclera and containing most of the blood vessels that supply the inside of the eye with oxygen and nutrients.

Tiny muscles attached to the choroid; they relax and contract to control how the choroid pulls on the zonule fibers to change the shape of the lens.

One of the two classes of photoreceptors, named for their distinctive shape.

A property of retinal circuits in which multiple photoreceptors send signals to one RGC.

A transparent membrane at the front of the eye; light enters the eye by first passing through the cornea, which sharply refracts the light.

The process of adjusting retinal sensitivity (changing the operating range) as the person moves from a bright environment to a darker one; the reverse process is called light adaptation.

Units used to express the power of a lens; diopters 5 1/(focal length).

A process by which the visual system makes edges as visible as possible, facilitating perception of where one object or surface ends in the retinal image and another begins.

A physical phenomenon that is simultaneously both a wave and a stream of particles.

The entire range of wavelengths of electromagnetic radiation.

Three pairs of muscles around each eye that enable us to move our eyes very rapidly and accurately and keep the eyes always pointed in the same direction.

The portion of the surrounding space you can see when your eyes are in a given position in their sockets.

Shadows on the retina thrown by debris within the vitreous humor; perceived as small, semitransparent spots or threads that appear to be floating before the person's eyes and tend to move with the eyes.

The distance from a lens at which the image of an object is in focus when the object is far away from the lens (at "optical infinity").

A region in the center of the retina where the light from objects at the center of our gaze strikes the retina; contains no rods and a very high density of cones.

The layer of the retina that contains retinal ganglion cells.

A condition in which the intraocular pressure is too high for the person's eye, most commonly caused by blockage of the openings that let aqueous humor drain from the anterior chamber.

Neurons in the inner nuclear layer of the retina.

A condition in which the optic axis is too short and accommodation cannot make the lens thick enough to focus light from a nearby object on the retina, so the light comes to a focus behind the retina, and the image on the retina is blurry; the person can see distant objects clearly but not nearby objects.

A technology used in night-vision devices; dim light is amplified by converting photons into electrons, amplifying the number of electrons, and then using the electrons to produce a pattern of varying intensities on a phosphor-coated screen

The layer of the retina that contains bipolar cells, horizontal cells, and amacrine cells.

The layer of the retina that contains the synapses among bipolar cells, amacrine cells, and RGCs.

The pressure of the fluids in the three chambers of the eye.

The colored part of the eyeÛa small circular muscle with an opening in the middle (the pupil) through which light enters the eye.

Different possible shapes of molecules, such as the all-trans retinal and 11-cis-retinal shapes of photopigment molecules.

Surgery to reshape the cornea in order to correct disorders of accommodation.

Inhibitory neural signals transmitted by horizontal cells in retinal circuits.

A transparent structure near the front of the eye that refracts the light passing through the pupil so that the light focuses properly on the retina.

Visible illumination; a type of electromagnetic radiation, corresponding to a small slice of wavelengths in the middle of the electromagnetic spectrum.

A difference in the intensity of illumination at adjacent retinal locations.

A condition characterized by damage to the photoreceptors in a region at the center of the retina; the leading cause of severe visual loss in the United States.

A condition in which the optic axis is too long and accommodation cannot make the lens thin enough to focus light from a distant object on the retina, so the light comes to a focus in front of the retina, and the image on the retina is blurry; the person can see nearby objects clearly but not distant objects.

The closest distance at which a person can bring an object into focus; presbyopia is characterized by a progressive increase in the distance from the eye to the near point as the person ages.

Devices to enable vision in total or near-total darkness.

The three main layers of the retina, including the outer nuclear layer, inner nuclear layer, and ganglion cell layer.

Receptive fields of RGCs with center-surround structure in which the RGCs decrease their firing rate when the amount of light striking the center of the receptive field decreases relative to the amount of light striking the surround.

Receptive fields of RGCs with center-surround structure in which the RGCs increase their firing rate when the amount of light striking the center of the receptive field increases relative to the amount of light striking the surround.

The visual system's sensitivity to the range of light intensities within the current scene; the visual system adjusts its operating range according to current conditions.

The spatial pattern of light rays, varying in brightness and color, entering your eyes from different locations in a scene.

An imaginary diameter line from the front to the back of the eye, passing through the center of the lens

Location on the retina where the axons of RGCs exit the eye; contains no photoreceptors.

Nerve formed by the bundling together of the axons of RGCs; it exits the eye through the optic disk.

The layer of the retina consisting of photoreceptors (but not including their inner and outer segments).

The layer of the retina that contains the synapses among photoreceptors, bipolar cells, and horizontal cells.

Brief, tiny bright flashes in the person's field of view not caused by light but by any of a variety of other causes.

A change in shape by a photopigment molecule from one isomer (11-cis retinal) to another (all-trans retinal) when the molecule absorbs a photon; initiates the transduction of light to a neural signal.

Single particles of light; a photon is the smallest possible quantity of electromagnetic radiation.

A molecule with the ability to absorb light and initiate transduction.

The process whereby photopigment molecules change back into the 11-cis shape after photoisomerization.

Retinal neurons (rods and cones) that transduce light into neural signals.

A layer of cells attached to the choroid; photoreceptors are embedded in it.

The space between the iris and the lens, filled with aqueous humor.

The type of stimulus that produces a neuron's maximum firing rate; for RGCs with on-center receptive fields, the preferred stimulus is a spot of light that exactly fills the center of the receptive field.

A common condition in which the lens becomes less elastic with age, characterized by a progressive increase in the distance from the eye to the near point as the person ages; as in hyperopia, accommodation can't make the lens thick enough to focus light from nearby objects

An opening in the middle of the iris, through which light enters the eye.

The automatic process by which the iris contracts and relaxes to control the size of the pupil, in response to the relative brightness of light entering the eye.

The region of a sensory surface that, when stimulated, causes a change in the firing rate of a neuron that "monitors" that region of the surface; the receptive field of an RGC is the region of the retina occupied by the photoreceptors to which the RGC is connected.

The inner membrane of the eye, made up of neurons, including the photoreceptors that convert the light entering the eye into neural signals. s (RGCs)

Neurons in the ganglion cell layer of the retina.

A clear image on the retina of the optic array.

An inherited condition in which there is gradual degeneration of the photoreceptors over many years, often leading to night blindness and "tunnel vision."

Individuals with a very rare genetic disorder in which the retina develops with rods but without cones; used in dark adaptation experiments to establish the curve for rods.

One of the two classes of photoreceptors, named for their distinctive shape.

The outer membrane of the eye; a tough protective covering whose visible portion is the white of the eye and the transparent cornea at the front of the eye.

A property of retinal circuits with convergence in which signals from photoreceptors in some small space on the retina summate (add up) to affect the response of the RGC in the circuit.

The degree to which a photopigment molecule absorbs light of different wavelengths.

A disorder of the extraocular muscles in which the two eyes are not aligned with one another, resulting in a double image, which impairs binocular depth perception.

In the retina, two layers separating the three nuclear layers the outer synaptic layer and inner synaptic layer.

A technology used in night-vision devices; infrared radiation emitted by objects and surfaces in a scene are converted into a visible electronic image.

The main interior portion of the eye, filled with vitreous humor.

A clear, somewhat gel-like fluid filling the vitreous chamber of the eye.

The distance between two successive peaks of a wave; different types of electromagnetic radiation are defined by their differences in wavelength.

Fibers that connect the lens to the choroid; they pull on the lens to change its shape.

Retinal ganglion cells that send signals to the koniocellular layers of the lateral geniculate nucleus.

Neurons in area V1 that respond best to a stimulus with a particular orientation; differ from simple cells in the variety and location of stimuli that generate a response.

Opposite-side organization, in which stimulation of neurons on one side of the body or sensory organ is represented by the activity of neurons in the opposite side of the brain.

A small volume of neural tissue running through the layers of the cortex perpendicular to its surface; consists of neurons that respond to similar types of stimuli and that have highly overlapping receptive fields.

The nonuniform representation of visual space in the cortex; the amount of cortical territory devoted to the central part of the visual field is much greater than the amount devoted to the periphery.

A visual pathway that runs from V1 and V2 into MT and then to the parietal cortex; represents properties that relate to an object's motion or location and that can be used to guide actions.

The specialization of different neural pathways and different areas of the brain for representing different kinds of information.

An area in the fusiform gyrus of the IT cortex; a functional module that responds selectively to faces.

The cortex in the bottom part of the temporal lobe; one of the object-selective regions of the visual system.

Layers of the lateral geniculate nucleus containing neurons with very small cell bodies.

Part of the thalamus (one in each hemisphere); receives visual signals via the axons of retinal ganglion cells.

An area of the occipital lobe; one of the object-selective regions of the visual system.

Layers of the lateral geniculate nucleus containing neurons with large cell bodies.

Retinal ganglion cells that send signals to the parvocellular layers of the lateral geniculate nucleus.

An area in the middle temporal lobe consisting of neurons that respond selectively to the direction and speed of motion of stimuli.

A function of brain areas in which signals from different sensory systems are combined.

Cortical columns consisting of neurons that receive signals from the left eye only or the right eye only.

A deficit in the ability to guide movements visually.

The location where the optic nerves from the two eyes split in half, with half the axons from each eye crossing over to the other hemisphere of the brain.

The continuation of the optic nerve past the optic chiasm; the right optic tract consists of axons from the retinal ganglion cells in the right half of each retina, and the left optic tract consists of axons from the left half of each retina.

Cortical columns consisting of neurons with the same (or very similar) orientation tuning.

A curve on a graph that shows the average response of an orientation-tuned neuron such as a simple cell to stimuli with different orientations.

An area in the parahippocampal gyrus of the IT cortex; a functional module that responds selectively to large-scale spatial layouts such as landscapes and buildings.

Retinal ganglion cells that send signals to the magnocellular layers of the lateral geniculate nucleus.

Layers of the lateral geniculate nucleus containing neurons with small cell bodies.

A consistent difference in the patterning of the relative responses of a population of differently tuned neurons; used to compute perceptual features such as the orientation of a visual stimulus.

The stimulus orientation that tends to produce the strongest response from an orientation-tuned neuron such as a simple cell.

The part of the occipital lobe where signals flow from the lateral geniculate nucleus.

An arrangement of neurons in the visual system whereby signals from retinal ganglion cells with receptive fields that are next to each other on the retina travel to neurons that are next to each other in each visual area of the brain.

A type of neuron in area V1 that responds best to a stimulus with a particular orientation in the location of its receptive field.

A structure near the top of the brain stem (one in each hemisphere); its principal function is to help control eye movements.

An area in the occipital lobe consisting of neurons that respond selectively to the color of stimuli and to the curvature of edges.

A visual pathway that runs from V1 and V2 into V4 and then to the inferotemporal cortex; represents properties that relate to an object's identity, such as its color and shape.

Devices designed to help the blind see; relay signals from a camera or photocells to implanted stimulators that activate the visual system.

In object recognition, the use of mathematical probabilities to describe the process of perceptual inference.

The perception that an edge, or border, is "owned" by a particular region of the retinal image.

Representation of objects by patterns of activity across many regions of the brain.

The perception of a partially hidden edge as complete; one of the operations involved in perceptual interpolation.

The process by which the visual system determines the location, orientation, and curvature of edges in the retinal image.

A region of an image that is perceived as being part of an object.

A neuron that responds to a particular object at a conceptual level, firing in response to the object itself, a photo of it, its printed name, and so on.

A region of an image that is perceived as part of the background.

In perceptual organization, rules of thumb based on evolved principles and on knowledge of physical regularities.

Nonexistent but perceptually real edges perceived as a result of edge completion.

A characteristic of visual scenes in which many objects are scattered in 3-D space, with partial occlusion of various parts of objects by other objects.

Representation of an object by a module, a region of the brain that is specialized for representing a particular category of objects.

Refers to the fact that the world contains an enormous variety of objects.

The process by which the visual system combines separate regions of the retinal image that "go together" based on similar properties.

In vision, the interpretation of a retinal image using heuristics.

The process by which the visual system fills in hidden edges and surfaces in order to represent the entirety of a partially visible object.

A type of visual agnosia in which the person is unable to recognize faces, with little or no loss of ability to recognize other types of objects.

The perception of a partially hidden surface as complete; one of the operations involved in perceptual interpolation.

A type of visual agnosia in which the person is unable to recognize spatial layouts such as buildings, streets, landscapes, and so on.

A characteristic of regions of the retinal image that have approximately uniform properties.

The different retinal images that can be projected by the same object or category of objects.

An impairment in object recognition.