The seeing brain Flashcards
The effects of a stimulus on the sensory organs
Sensation
The elaboration and interpretation of a sensory stimulus based on, for example, knowledge of how objects are structured
Perception
The internal surface of the eyes that consist of multiple layers. Some layers contain photoreceptors that convert light to neural signals, and others consist of neurons themselves
Retina
A type of photoreceptor specialized for low levels of light intensity, such as those found at night
Rod cells
A type of photoreceptor specialized for high levels of light intensity, such as those found during the day, and specialized for the detection of different wavelengths
Cone cells
The region of space that elicits a response from a given neuron
Receptive field
The point at which the optic nerve leaves the eye. There are no rods and cones present there
Blind spot
The first stage of visual processing in the cortex; the region retains the spatial relationships found on the retina and combines simple visual features into more complex ones
Primary visual cortex (V1)
In vision, cells that respond to light in a particular orientation (or points of light along that line)
Simple cells
In vision, cells that respond to light in a particular orientation but do not respond to single points of light
Complex cells
In vision, cells that respond to particular orientations and particular lengths
Hypercomplex cells
Cortical blindness restricted to one half of the visual field (associated with damage to the primary visual cortex in one hemisphere)
Hemianopia
Cortical blindness restricted to a quarter of the visual field
Quadrantanopia
A small region of cortical blindness
Scotoma
The receptive fields of a set of neurons are organized in such a way as to reflect the spatial organization present in the retina
Retinotopic organization
A symptom in which the patient reports not being able to consciously see stimuli in a particular region but can nevertheless perform visual discriminations accurately
Blindsight
In vision, a pathway extending from the occipital lobes to the temporal lobes involved in object recognition, memory and semantics
Ventral stream
In vision, a pathway extending from the occipital lobes to the parietal lobes involved in visually guided action and attention
Dorsal stream
A region of the extrastriate cortex associated with color perception
V4
A region of the extrastriate cortex associated with motion perception
V5/MT
A failure to perceive color (the world appears in grayscale), not to be confused with colorblindness (deficient or absent types of cone cell)
Achromatopsia
A failure to perceive visual motion
Akinetopsia
The color of a surface is perceived as constant even when illuminated in different lighting conditions
Color constancy
The ability to detect whether a stimulus is animate or not from movement cues alone
Biological motion
A memory representation of the 3D structure of objects
Structural descriptions
A failure to understand the meaning of objects due to a deficit at the level of object perception
Apperceptive agnosia
A failure to understand the meaning of objects due to a deficit at the level of semantic memory
Associative agnosia
The process of segmenting a visual display into objects versus background surfaces
Figure-ground segregation
A region of the brain that is specialized for processing object shapes
Lateral occipital complex (LOC)
A failure to integrate parts into whole s in visual perception
Integrative agnosia
An understanding that objects remain the same irrespective of differences in viewing conditions
Object constancy
A reduced neural response to a stimulus, or stimulus feature, that is repeated
Adaptation (or repetition suppression)
The notion that the brain represents different categories in different ways (and/or different regions
Category specificity
Stored knowledge of the 3D structure of familiar faces
Face recognition units (FRUs)
An abstract description of people that links together perceptual knowledge (ex: faces) with semantic knowledge
Person identity nodes (PINs)
An area in the inferior temporal lobes that responds more to faces than other visual objects, and is implicated in processing facial identity
Fusiform face area (FFA)
Impairments of face processing that do not reflect difficulties in early visual analysis (also used to refer to an inability to recognize previously familiar faces)
Prosopagnosia
The tendency to perceive ambiguous or hybrid stimuli as either one thing or the other (rather than as both simultaneously or as a blend)
Categorical perception
