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EEG (electroencephalogram)
a device that measures electrical activity in the brain, different behavioral states produce different and predictable EEG patterns
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PET (positron emission tomography)
a method of brain imaging that assesses metabolic activity by using a radioactive substance injected into the bloodstream; enables researchers to find brain areas using glucose for metabolic processes
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MRI (magnetic resonance imaging)
the researchers momentarily disrupt the magnetic force, and during this process, energy is released from brain tissue in a form that can be measured by detectors surrounding the head
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fMRI
an imaging technique used to examine changes in the activity of the working human brain, detects oxygen levels in blood; measures blood flow indirectly by assessing changes in the blood’s oxygen level
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TMS (transcranial magnetic stimulation)
the use of strong magnets to briefly interrupt normal brain activity as a way to study brain regions (creates brief reversible lesions); especially used to evaluate motor function
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sensory neurons
afferent neurons; detect information from the physical world and pass that information along to the brain usually via spinal chord (sensory nerves that provide information from muscles are called somatosensory, general term for sensations experienced from within the body)
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motor neurons
efferent neurons; direct muscles to contract or relax, thereby producing movement; messages are sent from the brain back to the body
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interneurons
communicate within local or short-distance circuits; they integrate neural activity within a single area (rather than transmitting information to other brain structures or to the body organs)
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Acetylcholine (ACh)
the neurotransmitter responsible for motor control and the junction between nerves and muscles
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serotonin
a monoamine neurotransmitter important for a wide range of psychological acitivity, including emotional states, impulse control and dreaming
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binocular disparity
a cue of depth perceptions that is caused by the distance between a person's eyes, which provides each eue with a slightly different image
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amygdala
almond shaped mass of nuclei involved in emotional responses, hormonal secretions, and memory
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cingulate gyrus
a fold in the brain involved with sensory input concerning emotions and the regulation of aggressive behavior
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fornix
an arching, fibrous band of nerve fibers that connect the hippocampus to the hypothalamus
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hippocampus
a tiny nub that acts as a memory indexer -- sending memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieving them when necessary
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hypothalamus
small collection of nuclei that form the floor of the 3rd ventricle; important for the autonomic nervous system and endocrine system; controls functions necessary for the maintenance of homeostasis
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olfactory cortex
receives sensory information from the olfactory bulb and is involved in the identification of odors
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thalamus
a large, dual lobed mass of grey matter cells that relay sensory signals to and from the spinal cord and the cerebrum.
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remote sensing
perceiving information at a distance
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retina
layer of neurons along the back surface of the eye; contains photoreceptors (respond to light) and ganglions (who's axons form the optic nerve)
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rods
1st type of photoreceptor; sensitive to low levels of stimulation (black and white)
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cones
2nd type of photoreceptor; sensitive to colors; densly packed near the center of retina/fovea
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optic nerve
transmits visual information to the CNS; a bundle of ganglion cell axons
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area MT
neurons that are sensitive to movement and direction; lies in the middle temporal lobe region (dorsal pathway); sometimes called V5;
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area V4
region in the visual cortex containing cells that are thought to process color information
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tonotopic map
the spatial arrangement of where sounds of different frequency are processed in the brain; more posterior cells respond best to higher frequencies
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akinetopsia
selective loss of motion perception (movement looks like snapshots)
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angiography
imaging method used to evaluate the circulatory system in the brain; relevant for cerebral vascular accidents
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BOLD (blood-oxygenation level-dependent)
signal measured by magnetic detectors in an MRI; the changes in the ratio of oxygenated to deoxygenated blood; active neural regions show an INCREASE in BOLD as blood supply increases in area
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brain lesion
structural damage to the white or gray matter of the brain; can result from tumor, stroke, and degenerative disorders
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computed tomography (CT, CAT)
CT = advanced x-ray; allows for the reconstruction of 3-D space from the compressed 2-D image; noninvasive imaging method
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deep-brain stimulation (DBS)
electrical stmiulation of brain structures via an implanted electrode; can be used to treat some disorder's (ex: Parkinson's)
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double dissociation
provides a strong argument that the observed differences in performance reflect functional differences between the groups, rather than unequal sensitivity of the two tasks; present when one group is impaired on one task and the other group is impaired on another other task; in imaging, it is when one experimental manipulation produces changs in activation in one region and a different manipulation produces changes in activation in a different neural region; method used to develop functional models of mental/neural processes
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ERP (event related potential)
change in electrical activity that's time-locked to specific events such as the presentationn of a stimulus/onset of a response
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MEG (magnetoencephalography)
meausure of magnetic signals created by the brain; neuron electrical activity produces small magnetic fields; similar to ERP but better b/c magnetic spatial signals are less distorted by organic tissue (brain or skull)
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multiunit recording
physiological procedure in which an array of electroedes is inserted in the brain such that the activity of many cells can be recorded simultaneously
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receptive field
area of external space within a stimulus that must be presented to activate a cell; in addition to space, cells can be selective for other features (shape and color)
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retinotopic
a representation in which some sort of orderly spatial relationship is maintained; referring to a topographic map of visual space across a restricted region of the brain
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single dissociation
method used to develop functional models of mental/neural processes; simulations requre a program that explicitely specifieds the nammer in which information is respresented and processed; program can be used to generate new predictions
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voxel
smallest unit of 3D data that can be represented in an MRI
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Heschl's gyri
found in the area of primary auditory cortex in the superior temporal gyrus of the human brain; Brodmann areas 41 and 42; first cortical structure to process incoming auditory information
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excitoxins
form of lesioning that limits extent of the damage; ex: NMDA, ibotenic acid, kainic acid only kills cell bodies (soma); tissue destruction/non-reversible
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Diaschisis
a sudden loss of function in a portion of the brain connected to but at a distance of a damaged area; can be cause by excitotoxins
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neurotoxin
toxin that acts on membrane proteins (ion channels) of neurons; (tissue destruction/non-reversible) ex: 6-hydroxydopamine [6-OHDA] selectively kills dopaminergic neurons
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cryogenic depression
cooling; a small tube with cold water is run through a part of the brain; fully reversible; can be applied many times; dulls synaptic activity but doesn’t affect tracts in vicinity until below 10 degrees C; not very localizable; can damage tissue w/ prolonged exposure
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aspiration
method of lesioning where a suction device removes the targeted structures (not very precise); tissue removal
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pharmalogical inactivation
inactivate cells; ex: Na+ channel blockers: block action potential conduction; only type that can affect fibers (eg. anesthetics [lidocaine], neurotoxins [tetrodotoxin]); lasts 15-60 minutes in cell bodies and 90 minutes in axons; ex: inhibitory neurotransmitters: hyperpolarize neurons -- reduce probability of firing; inactivate neuronal cell bodies (where the receptors are located) and NOT passing axons
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stroke
loss of brain functions due to break in vasculature/disturbance in blood supply to the brain; can be due to ischemia (lack of blood flow) caused by blockage (thrombosis, arterial embolism) or a hemorrhage (leakage of blood)
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arteriosclerosis
buildup of fat/cholesterol that causes arteries to become rigid; when arteries are hardened/narrowed by buildup they are subject to embolism (blockage)
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aneurysms
weakening of blood vessel walls; makes them distend from pressure (cause by high blood pressure); risk of rupture; results from genetic diseases/bad diet; opposite of arteriosclerosis
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coup
injury that occurs under the site of impact with an object; type of trauma
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contra coup
ex: a fall backwards and a blow to the back of head leading to damage in the front of the head
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ethmoid ridge
body process right where ventral part of ventral cortex rests
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sphenoidal crest
sharp edge of a cavity where both sides of anterior temporal lobe sits
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orbitofrontal and anterior temporal contusions
result from the effects of the brain being pressed against hte ethmoid ridge and sphenoidal crest?
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hematoma
bleeding in the brain; subdural is when blood gathers inside the dura mater; epidural is when blood gathers outside the dura mater
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dura matter
outermost of 3 layers surrounding the brain
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chronic vs. accute hematomas
slow bleeding and build-up vs. rapid bleeding
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ICP
inter-cranial pressure
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electrophysiology
measurements of the electrical activity of neurons, particularly action potential activity; powerful method for studying brain-behavior correlates
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lateral inhibition
the capacity of an excited neuron to reduce the activity of its neighbors
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motion aftereffect
caused by the nerve cells signaling motion in the direction the stimulus is moving fatiguing after continuous firing activity; cells that don’t share the same preferences inhibit each other
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Subtraction Logic (fMRI and PET)
an attempt to find pattern between the cognitive task and blood flow; subtract the blood flow in a control state from blood flow during the completion of a cognitive task; what's left is the neural activity that corresponds only to that task (not integrative brain function)
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Imaging (EEG, MEG, PET, fMRI) identifies areas _______ in a function; optical imaging Lesions (neuropsychology, animal lesions, TMS) can identify areas _________ for a function
INVOLVED; NECESSARY
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6 layers of the LGN (the later geniculate nucleus)
parvocellular (top): layers 3-6; process info about form, color, texture, GOOD spatial resolution, poor temporal resolution
magnocellular (bottom): layers 1-2; primarily process information about motion; good temporal but POOR spatial resolution
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Primary Visual Cortex (V1)
made up of stereo (depth?), color, and line (edge) orientation specific cells; bars are optimal stimulus; (optimal stimulus in V4 is complex objects excite, such as pinwheels)
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Quadranopsia
hemianopsia of only the lower or upper quadrant, according to whether the lesion is parietal or temporal; so an upper right visual field deficit corresponds to damage in the lower left visual hemisphere
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Hemianopsia
whole half of a hemisphere (left or right) can’t be seen; causes include stroke, tumor, trauma
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Scotoma
common small deficit, small visual field cut in specific location; everyone has one: blind spot, where optic nerve innervates the retina
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"Where" pathway
V1 dorsal route to posterior parietal cortex; allows recognition of where things are; use location of objects to make motion; passes through superior longitudinal fasciculus; thought to form maps of “salience" to guide motor behavior
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"What" pathway
route through inferior temporal lobe; these two processing streams share common feature: as you move further away from V1, the types of information represented gets much more complex; receptive fields include more of the foveal region than in dorsal stream; passes through inferior longitudinal fasciculus
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Superior Temporal Sulcus
responsible for biological motion (dots = walking 'man'); is anterior to MT, sits squarely between dorsal and ventral streams
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