Sensation and Perception Terms Flashcards
achromatopsia
A selective disorder of color perception
resulting from a lesion or lesions of the central nervous system, typically in the ventral pathway of the visual cortex. In achromatopsia, the deficit in color perception is disproportionately greater than that associated with form perception. Colors, if perceived at all, tend to be muted
acuity
The capacity to accurately discriminate fine detail
adaptation
In perception, adjustments to the sensitivity of a sensory system to the current environment and to important changes in the environment. In physiology, the reduction in a firing rate that typically occurs in the sensory system when a stimulus is continuously present
akinetopsia
A selective disorder of motion perception
resulting from a lesion or lesions of the central nervous system. Patients with this fail to perceive stimulus
movement, created by either a moving object or their own motion, in a smooth manner. In severe cases, the patient may only infer motion by noting that the position of objects in the environment has changed over time, as if the patient were constructing dynamics through a series of successive static snapshots
area MT
Also “area V5”. A region in the visual cortex containing cells that are highly responsive to motion. _____ is part of the dorsal pathway, thought to play a role not only in motion perception, but also in representing spatial information.
area V4
A region in the visual cortex containing cells that are thought to process color information
chemical senses
The two senses that depend on environmental molecules for stimulation: taste and smell
cochlear nerve
Also “auditory nerve”. A branch of the vestibulocochlear nerve (8th cranial nerve) that carries auditory information from synapses with hair cells of the cochlea to the cochlear nucleus in the brainstem
cochlear nuclei
Nuclei in the medulla where the cochlear nerve synapses
cones
Photoreceptors that are concentrated in the fovea,
providing high acuity but requiring higher levels of light than rods require to activate. ____ can replenish their pigments more quickly than rods can, and thus provide better daylight vision. There are three types, each type sensitive to light of specific wavelengths, mediating color vision
cortical plasticity
The capacity of the brain to reorganize itself anatomically and functionally
cortical visual areas
Regions of the visual cortex that are identified on the basis of their distinct retinotopic maps. The areas are specialized to represent certain types of stimulus information, and through their integrated activity they provide the neural basis for visually based behavior
extrastriate visual areas
A subdivision of cortical visual areas that lie outside the striate cortex and are considered secondary visual areas because they receive input either directly or indirectly from the primary visual cortex
fovea
The central region of the retina that is densely packed with cone cells and provides high-resolution visual information
ganglion cells
A type of neuron in the retina. These cells receive input from the photoreceptors (rods and cones) and intermediate cells if the retina and send axons to the thalamus and other subcortical structures
glomeruli
The neurons of the olfactory bulb
inferior colliculus
A part of the midbrain that is involved in auditory processing
interaural time
The difference in time between when a sound reaches each of the two ears. This information is represented at various stages in the auditory pathway and provides and important cue for sound localization
lateral geniculate nucleus
The thalamic nucleus that is the main target of axons of the optic tract. Output from the _______ is directed primarily to the primary visual cortex
multisensory integration
The integration of information from more than one sensory modality.
nociceptors
Also “free nerve endings”. The somatosensory receptors that convey pain information
odorant
A molecule connected to the air that leads to the activation of the olfactory receptors and may be perceives as having a fragrance when processed through the olfactory system
olivary nucleus
A collection of nuclei in the medulla and pons that is the first site where auditory information from the right and left ears converges
photoreceptors
Specialized cells in the retina that transduce
light energy into changes in membrane potential.
They are the interface for the visual system between the external world and the nervous system. The human eye has two types: rods and cones.
primary auditory cortex
The initial cortical processing area of the auditory systen
primary gustatory cortex
The initial cortical processing area for gustation, located in the insula and operculum
primary olfactory cortex
The initial cortical processing area for olfaction, located at the ventral junction of the frontal and temporal cortices, near the limbic cortex
primary somatosensory cortex
The initial cortical processing area for somatosensation, including Brodmann areas 1, 2 and 3. This area of the brain contains a somatotopic representation of the body called the homunculus.
primary visual cortex
The initial cortical processing area for vision, located in the more posterior portion of the occipital lobe, also known as Brodmann area 17
proprioception
The awareness of one’s own body parts, such as limbs. This awareness arises from the information provided by specialized nerve cells and the linkage of the muscles and tendons
receptive field
Th e area of external space within which a
stimulus must be presented in order to activate a cell. For example, cells in the visual cortex respond to stimuli that appear within a restricted region of space. In addition to spatial position, the cells may be selective to other stimulus features, such as color or shape. Cells in the auditory cortex also have receptive fields. The cell’s firing rate increases when the sound comes from the region of space that defines its _________
retina
A layer of neurons along the back surface fo the eye. This contains a variety of cells including photoreceptors and ganglion cells
retinotopic map
A topographic representation in the brain
in which some sort of orderly spatial relationship is maintained that reflects spatial properties of the environment in an eye-based reference frame. For example, primary visual cortex contains a _______ map of the contralateral side of space, relative to the center of gaze. Multiple of these maps have been identified in the cortex and subcortex.
rods
Photoreceptors that have a lower threshold for light stimuli than cones have, and thus enable vision in low-light conditions. They are found in the periphery of the retina and not in the fovea. Many only connect to one ganglion cell
saccades
The rapid eye movement that are made to change fixation from one point to another, A ______ lasts 20 to 100 milliseconds.
secondary somatosensory cortex
The area of the brain that receives input from primary somatosensory cortex and processes higher-lever somatosensory information
superior colliculus
A subcortical visual structure located in
the midbrain. The superior colliculus receives input from the retinal system and is interconnected with the subcortical and cortical systems. It plays a key role in visuomotor processes and may be involved in the inhibitory component of reflexive attentional orienting.
synesthesia
A mixing of the senses whereby stimulation of one sense automatically causes an illusory perceptual experience in the same or another sense
tastant
A food molecule that stimulates a receptor in a taste cell to initiate the sensory transduction of gustation.
tonotopic map
A mapping of different frequencies onto the hair cells along the cochlear canal and also the auditory cortex, with neighboring frequencies represented in neighboring spatial locations
