Principles of Cognitive Neuroscience: Chapter 3

acuity - The ability of a sensory system to accurately discriminate spatial detail; usually tested by the ability to spatially discriminate two points, as in the Snellen eye chart exam for vision. Applies to all the sensory systems, but most obviously to vision and somatic sensation. aperture problem - The challenge of determining the speed and direction of a moving line when its ends are obscured by an opening such as a circular hole or a vertical rectangle. apparent motion - The sensation of motion elicited by presentation of a stimulus in two successive positions over a brief interval. binocular - Pertaining to both eyes. binocular rivalry - The bi-stable visual experience that occurs when the right and left eyes are presented with incompatible or conflicting images and visual perception alternates between the two images every few seconds. brightness - Technically, the apparent intensity of a source of light; more generally, a sense of the effective overall intensity of a light stimulus. cerebral achromatopsia - Loss of color vision as a result of damage to the visual cortex. color - The subjective sensations elicited in humans (and presumably many other animals) by different spectral distributions of light. color constancy - The similar color appearance of surfaces, despite different spectral returns from them; usually applied to the similar appearance of objects under different illuminants. color contrast - The different color appearance of surfaces despite similar spectral returns from them. color space - The depiction of human color experience in diagrammatic form by a space with three axes representing the perceptual attributes of hue, saturation, and color brightness. cortical association areas - The regions of cerebral neocortex that are not involved in primary sensory or motor proc