5 & 6 Development & Plasticity of the Brain & Vision Flashcards
Movement of cells after they have differentiated as neurons
Migration
Production of new cells
Proliferation
Process whereby neuron forms it’s axons and dendrites
Differentiation
Process by which glia produce insulating fatty sheaths that accelerate transmission
Mylination
Formation of synapses
Synagptogenesis
Chemical that promotes survival and activity of neurons
Neurotrophin
Voluntary eye movement away from normal direction
Improves as you get older
Antisaccade task
If it’s axon does not make contact with an appropriate post synaptic cell by a certain age, the neuron kills itself
Apoptosis
Stimulation on one finger excited mostly or entirely the same cortical area as another finger
Musicians cramp
Focal hand dystonia
Temporary loss of blood flow to a brain area
Stroke
Result of blood clot or other obstruction in an artery
Ischemia stroke
Less common
Result of ruptured artery, neurons are flooded with blood and excess oxygen, calcium, and chemicals
Hemorrhage
Accumulation of fluid which increases pressure on brain and probability of additional strokes
Edema
The region surrounding the immediate damage in a stroke
Cells in the penumbra
The decreases activity of surviving neurons after damage to other neurons
Because activity in once area stimulated another areas damage to the brain disrupts patterns of normal stimulation
Diaschisis
A destroyed cell body can not be replaced, damaged axons do grow back under certain circumstances
The re growth of axons
After loss of a set of axons, cells that lost their source of innervation react by secreting neurotrophins to induce other axons to form new branches
Collateral sprouts
Heightened sensitivity to a neurotransmitter after the destruction of an incoming axon
Denervation supersensitivity
Heightened sensitivity as a result of inactivity by an incoming axon
Disuse supersensitivity
A continuing sensation of an amputated body part can range from tingling to intense pain
Phantom limb
A limb that has lost its sensory input
You can you the arm you just choose not to
Deafferented limbs
After information reaches your nervous system you encode it. you store the information in terms of responses by neurons in these ways:
Which neurons respond
Their amount of response
Timing of their responses
Whatever excise a particular nervous establishes a special kind of energy unique to let nerve
Law of specific nerve energies
Center of the iris
Pupil
Rear surface of the
Retina
Located closer to the center of the Eye receive messages from receptors at back of the eye
Bipolar cells
Locate is still closer to the center of the eye, receives messages from bipolar cells
Ganglion cells
The exile gangly on cells join one other to form the optic nerve the travels to the
Brain
Additional cells that get information from bipolar cells and send it to other bipolar cells, other amacrine cells, and ganglion cells
Amacrine cells
Has no receptors
Blind spot
Tiny area specialized from acute, detailed vision
Packed tightly with receptors
Fovea
When trying to focus on something small on the ground focus on the
Fovea
Ganglion cells in fovea of humans and primates
Midget ganglion cells
Greater perception in fainter light
Peripheral vision
Abundant in periphery of retina
Respond to faint light, not useful in bright light
Rods
Abundant in and near fovea, less active in dim light, more useful in Bright light and essential for color vision
Cones
Chemicals and both the rods and cones are released energy was struck by light
Photo pigments
Ratio of rods to cones
120 million : 6 million per retina
Propose that we perceive color by comparing responses across a few types of receptors each of which was sensitive to a different range of wavelengths
The Trichromatic Young Helmoholtz Theory
Propose we perceive color through the relative rates of responses by three kinds of cones each kind maximally sensitive to a different set of wavelengths
Short wavelength medium wavelength and long wavelength cone types
Young Helmoholtz Theory
We perceive color in terms of opposites
Red to green
Yellow to blue
White to black
Ability to recognize colors despite changes in lighting
Color consistency
You perceived differences and brightness when there are none, perception of brightness of object requires comparing it to other objects
Brightness consistency
The cortex compares information from various parts of the retina to determine the brightness and color for each area
Retinex theory
Some people lack one or two of the types of cones
Some people have three kinds of cones but one is abnormal
Color vision deficiency
most ganglion cells axons go to _____ the part of the thalamus specialized for visual perception
Lateral geniculate nucleus
The reduction of activity and one there I’m by activity in neighboring neurons
Main function is to sharpen contrast to emphasize the borders of objects
Lateral inhibition
Part of the visual field that excites or inhibits it
each cell the visual system of the brain has one
Receptive field
Have small cell bodies and small receptive fields located mainly in or near fovia
Well-suited to detect visual details also respond to color
Parvocellular neurons
Have a larger cell bodies and receptive fields and are distributed evenly throughout the retina
Not color sensitive, respond strongly to moving stimuli and to large overall patterns but not to detail
Magnocellular neurons
Have small cell bodies but occur throughout the retina
Have several functions and their axons terminate in several locations
Konicellular neurons
Primary visual cortex
Also known as area V1
Located in optical cortex
People was damaged Area V1
Blindsight
Ability to respond to visual stimuli that they report that not seeing it
Has receptive field with six excitatory and inhibitory zones
Simple cell
Located in areas V1 & V2- does not respond to exact location of the stimulus. responds to pattern of light in a particular orientation anywhere within its large receptive fields
Complex cells
Resembles complex cells but has a strong inhibitory area at one end of its bar shaped receptive field
Border beyond which the cell ceases fire
End stopped cell (hypercomolex)
Neurons that indicates the presence of a particular feature
Feature detectors
Receives information from primary visual cortex, processes is further, and transmit it two additional areas
Secondary visual cortex (area V2)
Where pathway
Visual path in parietal cortex
Dorsal stream
What pathway
Collection of visual paths and temporal cortex
Ventral stream
Inability to recognize objects despite otherwise ssatisfactory vision
Visual agnosia
Area especially right hemisphere their response strongly to faces much more than to anything else
Fusiform gurus of ITC
Inability to recognize faces
Prosopagnosia
Area V4
Color perception
Area MT (V5) area MST (medial superior temporal cortex)
Motion perception
Respond selectively when something moves at a particular speed in a particular direction
Area MT
Respond best to more complex stimuli expansion contraction or rotation of large visual scene
Area MST
Activity doesn’t decrease while your eyes are following a moving object
Saccades
