Chapter 3 Flashcards
Retinotopic mapping
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
Functional Specialization
The specialization of different neural pathways and different areas of the brain for representing different kinds of information.
Optic Chiasm
The location where the optic nerve from the two eyes split in half, with half the axons from each eye crossing over to the other hemisphere of the brain
Optic tract
The continuation of the optic nerve past the optic chiasm, the right optic tract consists of axons from the retinal ganglion cells from the right half of the retina…left from left
Contralateral organization
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
Lateral geniculate nucleus
Part of the thalamus receives visual signals via the axons of retinal ganglion cells
Magnocellular layers
Layers of the lateral geniculate nucleus containing neurons with large cell bodies
Parvocellular layers
Layers of the lateral geniculate nucleus containing neurons with small cell bodies
Konicellular layers
Layers of the lateral geniculate nucleus containing cells with very small cell bodies
Parasol retinal ganglion cells
Retinal ganglion cells that send signals to the magnocellular layers of the lateral geniculate nucleus
Midget retinal ganglion cells
Retinal ganglion cells that send signals to the parvocellular layers of the lateral geniculate nucleus
Bistratified retinal ganglion cells
Retinal ganglion cells that send signals to the konicellular layers of the lateral geniculate nucleus
Superior colliculus
A structure near the top of the brain stem (one in each hemisphere); its principal function is to help control eye movement
Multi sensory integration
A function of brain areas in which signals from different sensory systems are combined
Primary visual cortex
The part of the occipital lobe where signals flow from the lateral geniculate nucleus
Simple cell
A type of neuron in area V1 that responds best to a stimulus with a particular orientation in the location of its receptive field
Preferred orientation
The stimulus orientation that tends to produce the strongest response from an orientation-tuned neuron such as a simple cell.
Orientation tuning curve
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
Population code
A consistent difference in the patterning of the relative responses of a population of differently tuned neurons
Complex cells
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
Corticol column
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
Ocular dominance columns
Corticol columns consisting of neurons that receive signals from the left eye only or the right eye only
Orientation columns
Corticol columns consisting of neurons with the same ( or very similar) orientation tuning
Cortical magnification
The non uniform 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.
Dorsal pathway
A visual pathway that runs from v1 and v2 into MT and then to the parietal cortex; represents properties that related to an objects motion or location and that can be used to guide actions
Ventral Pathway
A visual pathway that runs from v1 and v2 into v4 and then to the inferotemporal cortex; represents properties that relay to an objects identity
Optic ataxia
A deficit in the ability to guide movements visually
V4
An area in the occipital lobe consisting of neurons that respond selectively to the color of stimuli and to the curvature of edges
Inferotemporal cortex (IT cortex)
The cortex in the bottom part of the temporal lobe; one of the object-selective regions of the visual system
Lateral occipital cortex
An area of the occipital lobe; on of the object -selective regions of the visual system
Fusions face area (FFA)
An area in the fusiform gyrus of the IT cortex; a functional module that responds selectively to faces
Parahippocampal place area (PPA)
An area in the para hippocampal gyrus of the IT cortex; a functional module that responds selectively to large scale spatial layouts such as landscapes and buildings.
MT
An area in the middle temporal lobe consisting of neurons that respond selectively to the direction and speed of motion of stimuli
visual neuroprosthetic devices
Devices designed to help the blind see; relays signals from a camera or photocells to implanted stimulators that activate the visual system
