Term
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Definition
Magnetic Resonance Imaging:
Visualizing Brain Structure
High resolution images are constructed from the measurement of waves that hydrogen atoms emit when they're activated by radio-frequency waves in a magnetic field.
Clearer images than a CT scan.
Provides high spatial resolution and 3D images.
Produces 3D & 2D images
Produced by waves from hydrogen atoms |
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Computed Tomography:
Visualizing Brain Structure
Computer-assisted x-ray procedure used to visualize the brain and other internal structures.
Cerebral Computed Tomography: 8-9 scans of horizontal brain sections are taken, then computer into one 3D image
Fluids, tumors, concussions |
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Definition
Positron Emission Tomography:
Visualizing Brain Function
Provides images of brain activity
Radioactive 2-deoxyglucose (2-DG) is injected into the patient's carotid artery (one in the neck that feeds the ipsilateral cerebral hemisphere).
-2-DG's similarity to glucose (primary metabolic fuel of the brain) it is rapidly taken up by active cells, but it cannot be metabolized, and thus accumulates in active neurons or astrocytes until its broken down.
-Each PET scan is an image of the levels of radioactivity in various parts of one horizontal level of the brain, though many levels are scanned.
Only used when necessary!!!
Inject radioactive 2-DG (Glucose)
Done if damage was expected/ only when needed |
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Definition
Functional Magnetic Resonance Imaging:
Visualizing Brain Function
Used to measure brain activity
Produce images of the increase in oxygen flow in the blood to active areas of the brain
-Possible because oxygenated blood:
--Has magnetic properties
--Active areas of the brain take up more oxygenated than needed, therefore the blood accumulates in the active areas.
The BOLD Signal (Blood-oxygen-level-dependent):
-Understanding of it is still incomplete
-Thought that the magnitude of the BOLD signal is correlated with the rate of firing in a given area of the brain.
Four Advantages of fMRI over PET scans:
1) Nothing injected into the subject. 2)Provides both structural and functional information in the same image 3) Better spatial resolution 4) Produces 3D images of activity over the entire brain
Visualizing blood flow/oxygen use in the brain
Occurs more quickly than glucose consumption, so almost real time views of brain function |
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Term
| Recording Pyschophysiological Activity |
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Definition
Recording Physiological Activity from the body's surface:
Blood pressure, skin conduction response, etc.
Brain Activity:
EEG |
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Definition
Electroencephalogram
Measures gross electrical activity of the brain
Seizures, sleep |
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Definition
Invasive Animal Research Method:
Remove, damage, or destroy a part of the brain to observe impact on behavior.
Aspiration lesions: Suction
Radio-frequency lesions: Heat destroys tissue
Knife cuts
Cryogenic Blockade: "Reversible lesion" Least used, but most nice |
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Definition
Invasive Animal Research Method:
Electrical stimulation may be used to "activate" a structure.
Opposite of Lesioning |
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| Routes of Drug Administration |
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Definition
Pharmacological Research Method:
Fed to subject- closer to real world, less stress, but less control
Injected: Described by injection site
Cannula |
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Definition
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Definition
| Pentoneal Cavity injection |
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Definition
| Injection to a large muscle |
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Definition
| Injected into tissue under the skin |
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Definition
| Injected into a large surface vein |
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Definition
Used to administer drug directly to the brain
Gets around BBB
More control, more immediate |
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Definition
Based on the binding of labeled protein-specific anitbodies
Used in locating NTs and Receptors |
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Definition
Genetic Engineering
Create organisms that lack a particular gene under investigation
Antisense drugs potentially circumvent some problems with gene knockout techniques
Knockout mice
Subjects missing a given gene can provide insight into what the gene controls |
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Term
| Gene Replacement Techniques |
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Definition
Genetic Engineering
Replacing one gene with another that's slightly modified
Transgenic Mice- mice that contain genetic material of another species. |
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Term
| Seminatural Learning Paradigms |
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Definition
Mimic situations that an animal might encounter in its natural environment
Conditioned taste aversion, Radial Arm Maze, Morris Water Maze, Conditioned Place Preference, Conditioned Defensive Burying |
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Term
| Conditioned Taste Aversion |
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Definition
Animals appear prepared to associate tastes and illness
Avoidance response that develops to tastes of food that made it ill.
Rats are given an emetic (nausea-inducing drug) along with an unfamiliar food and they learn to avoid that taste |
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Term
| Radial Arm Maze and Morris Water Maze |
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Definition
| Tests spatial abilities and memory |
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Term
| Conditioned Place Preference |
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Definition
| Dark and light room, mice prefer darkness, but conditioned to be in light room. |
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Term
| Conditioned Defensive Burying |
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Definition
A single aversive stimulus (like a shock( is administered from an object mounted on the cage wall near the ground
Rat responds to threat by flinging bedding material at it
Used in the study of anxiety |
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Term
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Definition
Waves of electromagnetic energy
Light entering the eye is the basis for seeing.
Nothing can see in complete darkness |
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Definition
| Plays an important role in the perception of color |
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Definition
| Plays an important role in the perception of brightness |
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Definition
The hole in the iris and where light enters the eye
Adjustment of pupil size is a response to illumination changes
-A compromise between:
--Sensitivity: The ability to detect the presence of dimly lit objects
--Acuity: The ability to see the details of an object
-In bright light, the pupil is constricted, thus the images falling on he retina are sharper and there is greater focus/detail |
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Term
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Definition
| Colored, donut-shaped bands of contractile tissue that regulate the amount of light reaching the retina |
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Term
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Definition
Located behind the pupil, they focus incoming light on the retina
Ciliary Muscles adjust ligaments holding lens in place, thus increasing lens' ability to refract (bend) light, bringing objects into sharper focus
-Lens is flattened to see distant objects
-Accommodation is what this process is called |
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Definition
Side-by-side allows for perceptions of depth.
Convergence- turning of the eyes slightly inward to see, particularly when objects are close.
Binocular disparity. |
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Definition
Image on two retinas can never correspond exactly because eyes can never be in exactly the same position.
The difference is greater for close objects |
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Term
| The Retina: Five Layers of Different Types of Neurons |
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Definition
Variety of Subtypes
Retinal Ganglion Cells
Amacrine Cells
Bipolar Cells
Horizontal Cells
Receptors:
-Cones
-Rods
Amacrine and Horizontal Cells are specialized for lateral communication (communication across major channels of sensory input) |
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Term
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Definition
Light reached the receptor layer after passing through the other four layers.
Once receptors have been activated, the neural message is transmitted back out though the retinal layers to the retinal ganglion cells, whose axons project across the inside of the retina before gathering together in a bundle and exiting the eyeball.
Creates two visual problems:
-Incoming light is distorted by retinal tissue.
--Minimized by the fovea, an indentation at the center of the retina, specialized for high-acuity.
---Retinal ganglion cell layer thins here, reducing the distortion of incoming light.
-In order for bundle of retinal ganglion cells to leave the eyeball, there must be a gap in the receptor layer, called the blind spot.
--Blind spot fixed by completion (filling in)
---Visual system uses information provided by the receptors around the blind spot to fill in the gaps in retinal images
---Surface interpolation: process by which we perceive surfaces; the visual system extracts information about edges and from it, infers the appearance of large surfaces. |
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Term
| The Retina: Cone and Rod Vision |
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Definition
Duplexity Theory: Cones and rods mediate different kinds of vision.
Photopic Vision
Scotopic Vision
Distribution
-Only cones in the fovea
-More rods in the nasa hemiretina than in the temporal hemiretina |
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Term
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Definition
Cone-mediated vision
Predominates in good lighting and provides high-acuity, color perceptions.
In dim lighting, there's not enough light to reliably excite the cones. |
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Term
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Definition
Rod-Mediated Vision
Predominates in dim lighting.
Lacks the same detail and color perception as photopic vision. |
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Term
| The Retina: Spectral Sensitivity Curve |
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Definition
Photopic Spectral Sensitivity Curve
Scotopic Spectral Sensitivity Curve
Purkinje Effect |
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Term
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Definition
Visual Field is the entire area that one can see at a particular movement
-All of what we see is determined not just by what is projected onto the retina at that instant
--Eye constantly scanning our visual field
--Visual perception is sum of all recent visual information
---Temporal Integration
-Even when eyes are fixated on an object, our eyes continuously move.
--Fixational Eye Movements (Three Kinds):
---Tremor, drifts, and saccades (small, jerky movements)
---Allow us to see when our eyes are fixated. |
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Term
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Definition
Conversion of light into neural signals.
Transduction is the conversion of one form of energy to another.
Visual transduction is the conversion of light to neural signals by the visual receptors.
Pigment- any substance which absorbs light.
Rhodopsin- a red pigment that became bleached (lost all color) and ability to absorb color when exposed to continuous light; in the dark it regained both redness and light absorbing capacity.
-Light-absorbition and bleaching is the first step in rod-mediatied vision
-Absorbtion spectrum
-A G-protein receptor that responds to light rather than NT molecules
--Initiate a cascade of intracellular chemical events when activated.
-When rods are in darkness, sodium channels partially open, keeping the rods slightly depolarized and allowing a steady flow of excitatory glutamate NT molecules to emanate from them.
-Rhodopsin receptors, when bleached by light, close sodium channels, hyperpolarizes the rods, and reduces the release of glutamate.
-Neural signals are often transmitted by inhibition.
-Less is known about cone photopigments, but they appear similar to rhodopsin |
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Term
| From Retina to Primary Visual Cortex: Retina-Geniculate-Striate Pathway |
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Definition
Many Pathways carry visual information to the brain.
Retina-Geniculate-Striate Pathways
(Geniculate= LGN; Striate=Primary Visual Cortex)
-~90% of axons of retinal ganglion cells
-Conducts signals from each retina to the primary visual cortex, or striate cortex, via the lateral geniculate nuclei (LGN) of the thalamus.
-About 90% of retinal ganglion cells become part of this pathway.
-All signals from the left visual field reach the right primary visual cortex and vice versa.
--Ipsilaterally: from temporal hemiretina of right eye
--Contralaterally: from nasal hemiretina of left eye
-Each LGN has six layers and each one receives input from all parts of the contralateral visual field of one eye
--Three layers from one eye; three from the other
--Most of the LGN projects to the primary visual cortex terminate in the lower part of cortical layer IV, giving a stripe, or striation, when viewed in cross section.
-Retinotopic: each level of the system is organized like a map of the retina
--Disproportionate representation of the fovea, a very small part of the retina, but a fairly large proportion of the primary visual cortex, ~25%, is dedicated to analysis of its input.
-Two parallel channels of communication flow through each LGN: P and M channels
-The P and M cellular neurons project to slightly different sites in the lower part of layer IV of the striate cortex and thus project to different parts of the visual cortex.
-Move from simple to complex
-Information goes to the thalamus in a organized fashion and leaves in one. |
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Term
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Definition
Top four layers of the LGN, through which one channel runs.
"Parvo" means small; composed of neurons with small cell bodies.
Particularly responsive to color, fine pattern details, and to stationary or slow moving objects.
Receive the majority of input from cones |
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Term
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Definition
Bottom two layers of the LGN, through which the other channel runs.
"Magno" means large; neurons with large cell bodies.
Particularly responsive to movement.
Receive the majority of input from rods. |
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Term
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Definition
| Edges are the most informative features of any visual display because they define the extent and position of the various objects in it. |
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Definition
Merely the place where two different areas of visual images meet.
-Perception of an edge is really the perception of a contrast between two adjacent areas of the visual field. |
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Definition
The intensification of the perception of edges.
Mach Bands- non-existant stripes of brightness and darkness running adjacent to edges.
Our perception of edges is better than the real thing.
Firing rates of receptors are higher on each side of an edge.
Lateral Inhibition- inhibition of adjacent neurons or receptors in a topographic array
-Inhibition produced relies on intensity of illumination
Visual system detects change
Really wired to notice contrast
Firing of photoreceptors differently next to each other. |
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Definition
Nothing can be transduced
Eyes are constantly moving so we don't notice this.
Result of optic nerve leaving the retina |
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Definition
Center of the retina
High Acuity
Mostly cones |
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Term
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Definition
| Prevent habituation (desinsitized) |
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Term
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Definition
The pigment found in rods.
A G-protein-linked receptor that responds to light.
In the dark (dim light), Sodium channels open, rods are depolarized (meaning they're firing at maximum intensity. Excitatory neurotransmitter (glutamate) is released by rods.
When light strikes, sodium channels close, rods are hyperpolarized, glutamate release is reduced. |
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Term
| Process of Events in Vision |
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Definition
Photons of light-> Photoreceptors-> Bipolar cells-> Ganglion Cells.
Axons of the ganglion cells form the optic nerve. Optic nerves from each eye connect/cross at the optic chiasm (highly myelinated).
~90% of visual information then goes to the LGN of the thalamus and then to the visual cortex within the occipital lobe.
Other 10% goes to the superior colliculus in the midbrain.
-Relflexive, flash look, not well-thought out/planned; knee jerk reaction.
See left visual field with right-halves of eyes processed in right visual cortex |
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Term
| Receptive Fields of Visual Neurons |
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Definition
The area of the visual field within which it is possible for a visual stimulus to influence the firing of that neuron.
Visual system neurons tend to be continually active, thus effective stimuli either increase or decrease the rate of firing.
Three levels investigated: ganglion, LGN, cortex (lover layer IV of Primary Visual Cortex) neurons
Similarities:
-Circular receptive fields
--Circular boundary between excitatory and inhibitory areas
-Monocular
--Respond from information from one eye only
-Many had a center-surround organization.
Six layers of primary visual cortex, but we're only talking about the fourth.
On/off center ganglion cells
-Respond best to contrast
Receptive fields in foveal area are smaller than those at the periphery; constant with the fact fovea mediates high-acuity |
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Term
| Simple Receptive Fields in V1 Cortex (Primary Visual Cortex) |
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Definition
Rectangular.
"On" and "off" regions, like cells in layer IV.
-Divided by a straight line
-Unresponsive to diffuse light
Orientation and location sensitive.
All are monocular
-Respond to stimulation of only one eye |
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Term
| Complex Receptive Fields in V1 Cortex (Primary Visual Cortex) |
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Definition
Rectangular.
Larger Receptive Fields.
Do not have static "on" and "off" regions.
Not location sensitive.
Motion sensitive.
Many are binocular
-Responsive to stimulation of either eye
More numerous than simple cells
Respond best to straight-line stimulus |
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Term
| Organization of the Primary Visual (V1) Cortex |
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Definition
Cells with simpler receptive fields send information on to cells with more complex receptive fields.
Cells with the same response properties are organized in columns= Ocular dominance columns.
Retinotopic organization is maintained. |
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Term
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Definition
Young-Helmholz Trichomatic Theory
Proposed that three primary colors can be mixed to make all.
Supporting evidence- the retina has three types of cones with maximal sensitivities to red, green, and blue.
Additive mixing in the brain.
Best explains color vision at the level of the cones
3 Different kinds of color receptors (cones), each with different spectral sensitivity, and the color of a particular stimulus is presumed to be encoded by the ratio of activity in the three kinds of receptors |
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Term
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Definition
Proposed by Hering
Proposes opposing color processes exists-
Black/white
Red/green
Blue/yellow
Stimulation of one color inhibits its opposing color (afterimages)
Supported by afterimages.
Most common color blindness- red/green
Subsequent levels of visual pathway operate this way.
Two different classes of cells in the visual system for encoding color and another one for brightness.
-Each class encodes two complementary color perceptions, which are pairs of colors that produce white or grey when combined in equal measure |
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Definition
| Respond to lights shone in the central region of their receptive fields with "on" firing. To lights shone in the periphery of their receptor fields, they respond with inhibition, followed by an "off" firing when the light is turned off. |
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Definition
| Respond with inhibition and "off" firing in response to lights in the center and with "on" firing to lights in their periphery. |
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Definition
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Term
| Columnar Organization of the V1 |
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Definition
Simple to complex
Grouped in functional verticle columns
Some in horizontal columns |
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Term
| Plasticity of Receptive Fields of Neurons in the Visual Cortex |
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Definition
| Plasticity is a fundamental property of visual cortex function |
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Term
| Seeing Black, White, and Grey |
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Definition
Black- experienced when there's an absence of light
White-produced by an intense mixture of a wide range of wavelengths in roughly equal proportion.
Grey-produced by the same mixture as white, only at lower intensities. |
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Definition
Colors
Depend on wavelength of light, though this isn't the whole story... |
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Definition
Perceived color of an object isn't a simple function of the wavelengths reflected by it
-Tendency of an object to stay the same color despite major changes in wavelengths of light it reflects.
-Improves our ability to tell objects apart.
Retinex Theory
Dual-opponent color cells |
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Term
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Definition
The color of an object is determined by its reflectance (the proportion of light of different wavelengths that a surface reflects
-Efficiency of a surface to absorb and reflect unabsorbed portion remains unchanged in different lights. |
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Term
| Primary Visual (V1) Cortex |
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Definition
Receives most of its input from the visual relay nuclei of the thalamus (LGN)
Located in the posterior region of the occipital lobe |
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Term
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Definition
Receives most input from V1
Located in prestriate cortex (band of tissue in occipital lobe surrounding V1) and interotemporal cortex (cortex of the inferior temporal lobe) |
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Term
| Visual Association Cortex |
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Definition
Receive input from secondary visual cortex and secondary areas of other sensory systems.
Located in several parts of cerebral cortex, but largest area is in the posterior parietal cortex |
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Term
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Definition
An area of blindness in the corresponding area of contralateral visual field of both eyes to the damage.
-Tested by perimetry test
-Most people aren't conscious of this deficit because of completion.
-Hemianopsic- having a scotoma covering half of the visual field. |
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Term
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Definition
| Perceiving and being aware are inseparable |
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Term
| Damage to the V1: Blindsight |
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Definition
With damage, people are able to still see things, but have no conscious awareness of them.
Blindsight is the ability of people with scotomas to respond to visual stimuli in the scotoma even though they have no conscious awareness of their stimuli
-Perception of motion is the most likely to survive damages.
-Two ideas to explain Blindsight:
--Striate cortex not completely destroyed and remaining cells can mediate some visual abilities without conscious awareness.
--Visual pathways that go straight to secondary visual cortex without going to V1 can maintain some visual abilities |
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Term
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Definition
Flows from V1 to dorsal prestriate cortex to posterior parietal cortex
Spatial abilities
"Where"
Direct behavioral interactions with objects |
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Definition
Flows from V1 to ventrical prestriate cortex to inferotemporal cortex
Characteristics of objects- color, shape
"What"
Conscious perception of objects |
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Term
| "What" vs. "Where" Theory |
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Definition
Dorsal stream specialized in visual spatial perception
Ventral stream specializes in visual pattern recognition
Predicts:
-Damage to the dorsal stream disrupts visual spatial perception
-Damage to ventral stream disrupts visual pattern recognition |
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Term
| "Control of Behavior" vs. "Conscious Perception" Theory |
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Definition
Dorsal stream specializes in visually guided behavior
Ventral steam specializes in conscious visual perception
Predicts:
-Damage to dorsal stream disrupts visually guided behavior, but not conscious visual perception
-Damage to the ventral stream disrupts conscious visual perception, but not visually guided behavior. |
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Term
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Definition
Visual agnosia for faces
Visual agnosia is a specific type for visual stimuli:
-The stimuli is seen, but not recognized.
Can recognize a face is a face, but not whose, mostly.
Perhaps more than just faces?
-Problem with specifics in complex classes of objects
Results from bilateral damage to ventral stream
-Dorsal stream possibly still intact, thus unconscious ability to recognize faces |
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Term
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Definition
| Failure of recognition that isn't attributable to a sensory deficit or intellectual impairment |
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Term
| Hierarchical Organization of Sensory Systems |
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Definition
Simple to complex.
Receptors-> Thalamic Relay Nuclei-> Primary Sensory Cortex->Secondary Sensory Cortex-> Association Cortex.
Sensation and Perception |
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Term
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Definition
| Process of detecting the presence of stimuli |
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Definition
| Higher-order process of integrating, recognizing, and interpreting complete patterns of sensations |
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Term
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Definition
| Each sensory system contains functionally distinct areas that specialize in different kinds of analysis |
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Term
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Definition
Parallel Systems- information flows through the components over multiple pathways
Stimulates analysis of a signal in different ways by the multiple parallel pathways of a neural network
-Two Different Parallel Streams of analysis:
--One capable of influence behavior without conscious awareness
--One that influences behavior with conscious awareness |
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Term
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Definition
Vibrations of air molecules that stimulate the auditory system
Humans can only hear vibrations between 20 and 20,000 hertz
Travels in the form of a wave
-Amplitude: height=loudness
-Frequency: speed=pitch (Faster is higher)
-Complexity:timbre/richness of sound |
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Definition
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Term
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Definition
| Mathematical procedure for breaking complex, real world sound waves into pure (sine) waves of a lab. |
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Definition
Soundwaves travel down the auditory canal and cause the tympanic membrane (eardrum) to vibrate.
Vibrations are then transferred to the three ossicles (small bones of the middle ear): malleus (hammer), incus (anvil), and stapes (stirrup).
Vibrations of the stripes trigger vibrations of the oval window, which then transfers vibrations to the fluid of the cochlea (a long, coiled tube with an internal membrane running almost to its tip)
-This internal membrane is the Organ of Corti, the auditory receptor organ
Organ of Corti:
-Each pressure change at oval window travels here as a wave
-Two membranes:
--Basilar Membrane
---Where hair cells are mounted
----Hair cells are the auditory receptors
--Tectorial Membrane
---Rests on hair cells
-Any deflection produces force on the hair cells which then stimulates them and causes action potentials in the axons of the auditory nerve.
The ear is organized primarily in tonotopic fashion- according to the frequency of sound. |
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Term
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Definition
| Receptive organs of vestibular system, which carries information about the direction and intensity of hear movements, helping us maintain balance |
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Term
| From Ear to Primary Auditory Cortex |
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Definition
A network of auditory pathways.
Axons of each auditory nerve synapses in the ipsilateral cochlear nuclei, from which many projections lead to the superior olives. These project to the inferior colliculi, via the lateral lemniscus, where they synapse on neurons that project to the medial geniculate nuclei of the thalamus, which then projects to the Primary Auditory Cortex, which then goes to the Secondary Auditory cortex in the temporal lobe.
Pathways are crossed.
Subcortical component- localization of sounds in space |
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Term
| Effects of Damage to the Auditory System |
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Definition
Auditory cortex is rarely destroyed in its entirety.
Deafness:
-Damage to inner or middle ear, or the nerves leading away from them.
--Conductive Deafness: damage to ossicles
--Nerve Deafness: damage to cochlea or auditory nerve.
---Major cause is hair cell receptor loss
Tinnitus: Ringing of the earls
Cochlear Implants: convert sounds to electrical signals for the ear. |
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Term
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Definition
Adaptive, no cortical representation, descending pain control.
Anterior Cingulate Cortex: Most linked to experience of pain
-Emotion reaction rather than perception
-Gate-Control Theory: Ability of cognitive and emotional factors to block pain.
--Periaqueductal Grey (PAG) has pain-blocking effects
--Specialized receptors for opiate drugs
--Isolation of endorphines, internally made opiate drugs.
Descending pathway involving opiate activity in the PAG and serotonergic activity in the raphé nuclei model.
Neuropathic Pain- severe chronic pain in the absence of a recognizable pain stimulus. |
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Term
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Definition
Pinna- helps to direct sounds
Eardrum- amplify soundwaves |
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Term
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Definition
Three Ossicles bang together to further amplify soundwaves
Smallest bones in the body
Stirrup, Anvil, Hammer |
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Term
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Definition
Cochlea- contains fluids that rock with soundwaves
-Basilar membrane on bottom, with hair cells which bend, causing transduction
Oval Window |
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Term
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Definition
Olfaction (smell) and gustation (taste) monitor the chemical content of the environment.
-Work together when we eat
-Flavor: integrated sensory impression
-Pheromones: Chemicals that influence the physiological and behavior of conspecifics (others of the same species)
--No direct evidence to suggest human odors can serve as sexual attractants
-Learning:
--Conditioned aversion
--I-want-a-girl-just-like-the-girl-who-married-dear-old-dad Phenomenon |
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Term
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Definition
Olfactory receptors are located in the upper part of the nose, embedded in a layer of mucus-covered tissue called the olfactory mucosa
-Dendrites in nasal passages, axons pass through the cribriform plate, (porous portion of skull), then enter the olfactory bulbs where they synapse on neurons that project via the olfactory tracts to the brain.
-In mammals, olfactory receptor cells each contain only one type of receptor protein molecule
--One-olfactory-receptor-one-neuron rule
-Receptor proteins are in dendrite membranes where they're stimulated by circulating airborn chemicals in the nasal passages.
-All receptors with same protein project to the same general location in the olfactory bulb.
-Different odors produce different spacial patterns of activity on olfactory bulbs.
--Detected with 2-DG technique
-Each odor seems to be encoded by component processing (by the pattern of activity across many receptor types)
-New receptor cells are created throughout each individual's life to replace deteriorated ones
--Once created, they develop axons which grow until they reach the appropriate sites
--Only survives a few weeks before being replaced
An Olfactory Tract projects to several structures of the medial temporal lobes, including the amygdala and the piriform cortex (adjacent to the amygdala, it's considered to be the primary olfactory cortex)
-Only sensory system that reaches the cerebral cortex without first going through the thalamus. |
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Term
| Two Major-Pathways leaving amygdala-piriform area |
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Definition
One projects to the limbic system
-Thought to mediate the emotional response to smell
One projects via the medial dorsal nuclei of the thalamus to the orbitofrontal cortex (the area of cortex on the inferior surface of frontal lobes, next to he orbits, or eye sockets)
-Thought to mediate the conscious perception of odors
Little is known about how neurons receptive to different odors are organized in the cortex. |
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Term
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Definition
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Definition
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Term
| Top-Down Processing in OFC |
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Definition
| Bias, expectation, experience effects how sensory info is perceived. |
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Definition
Pixel with volume
Looking at 3D objects
fMRIs |
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Term
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Definition
Taste receptors are found on the tongue and in parts of the oral cavity.
-Typically in clusters of about 50, called taste buds.
--Often located around small protuberances called papillae
-Don't have own axons; each neuror that carries impulses away from a taste bud receives input from many receptors. |
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Term
| At Least Five Primary Tastes |
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Definition
Sweet, sour, bitter, salty, and unami (Meaty or savory)
-Many tastes cannot be created by combinations of these.
-Salty and sour have no specific receptor sites for themselves
--Influence activity of various receptors by acting on ion channels. |
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Term
| Gustatory System: Major Pathways |
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Definition
Papillae, tastes, receptors-> cranial nerves-> nucleus of solitary tract (NST)-> thalamus-> Primary gustatory cortex-> Secondary gustatory cortex
Primarily ipsilateral |
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Term
| Brain damage and Chemical Senses |
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Definition
Anosmia: Inability to smell
-Blow to the head causes brain displacement, that crushes olfactory nerves
Ageusia: Inability to taste
-Rare
-Partial Ageusia: after damage to an ear, anterior two-thirds of tongue is tasteless. |
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Term
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Definition
Improves perception of stimuli in focus
Interferes with perception of stimuli not in focus.
Endogenous Attention: internal cognitive processes
-Mediated by top-down neural processes.
Exogenous Attention: external events
-Mediated by bottom-up neural processes.
Eye Movement and Visual Attention:
-Overt attention: change in visual attention because a shift in gaze.
-Covert Attention: change in visual attention without a shift in gaze
Cocktail-Party-Phenomenon: brain can block from conscious awareness all stimuli except those of a particular kind while unconsciously monitoring block-out stimuli incase something important comes up. |
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Definition
We have no memory for parts of a scene that aren't the focus
Because of this, people with change blindness have no memory for what they're mind didn't attend to. |
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Term
| Neural Mechanisms of Attention |
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Definition
Focused mainly on visual attention
Thought to work by strengthening the neural responses to attend-to aspects and by weakening the response of others.
-Anticipation of stimulus increases neural activity
Dorsal and Ventral Streams |
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Term
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Definition
Difficulty in attending to more than one object at a time.
Can be visual |
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