2) Cog Neuro


EEG (electroencephalogram)


a device that measures electrical activity in the brain, different behavioral states produce different and predictable EEG patterns


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


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


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


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


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)


motor neurons


efferent neurons; direct muscles to contract or relax, thereby producing movement; messages are sent from the brain back to the body


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)


Acetylcholine (ACh)


the neurotransmitter responsible for motor control and the junction between nerves and muscles


serotonin


a monoamine neurotransmitter important for a wide range of psychological acitivity, including emotional states, impulse control and dreaming


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


amygdala


almond shaped mass of nuclei involved in emotional responses, hormonal secretions, and memory


cingulate gyrus


a fold in the brain involved with sensory input concerning emotions and the regulation of aggressive behavior


fornix


an arching, fibrous band of nerve fibers that connect the hippocampus to the hypothalamus


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


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


olfactory cortex


receives sensory information from the olfactory bulb and is involved in the identification of odors


thalamus


a large, dual lobed mass of grey matter cells that relay sensory signals to and from the spinal cord and the cerebrum.


remote sensing


perceiving information at a distance


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)


rods


1st type of photoreceptor; sensitive to low levels of stimulation (black and white)


cones


2nd type of photoreceptor; sensitive to colors; densly packed near the center of retina/fovea


optic nerve


transmits visual information to the CNS; a bundle of ganglion cell axons


area MT


neurons that are sensitive to movement and direction; lies in the middle temporal lobe region (dorsal pathway); sometimes called V5;


area V4


region in the visual cortex containing cells that are thought to process color information


tonotopic map


the spatial arrangement of where sounds of different frequency are processed in the brain; more posterior cells respond best to higher frequencies


akinetopsia


selective loss of motion perception (movement looks like snapshots)


angiography


imaging method used to evaluate the circulatory system in the brain; relevant for cerebral vascular accidents


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


brain lesion


structural damage to the white or gray matter of the brain; can result from tumor, stroke, and degenerative disorders


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


deep-brain stimulation (DBS)


electrical stmiulation of brain structures via an implanted electrode; can be used to treat some disorder's (ex: Parkinson's)


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


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


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)


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


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)


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


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


voxel


smallest unit of 3D data that can be represented in an MRI


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


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


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


neurotoxin


toxin that acts on membrane proteins (ion channels) of neurons; (tissue destruction/non-reversible) ex: 6-hydroxydopamine [6-OHDA] selectively kills dopaminergic neurons


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


aspiration


method of lesioning where a suction device removes the targeted structures (not very precise); tissue removal


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


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)


arteriosclerosis


buildup of fat/cholesterol that causes arteries to become rigid; when arteries are hardened/narrowed by buildup they are subject to embolism (blockage)


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


coup


injury that occurs under the site of impact with an object; type of trauma


contra coup


ex: a fall backwards and a blow to the back of head leading to damage in the front of the head


ethmoid ridge


body process right where ventral part of ventral cortex rests


sphenoidal crest


sharp edge of a cavity where both sides of anterior temporal lobe sits


orbitofrontal and anterior temporal contusions


result from the effects of the brain being pressed against hte ethmoid ridge and sphenoidal crest?


hematoma


bleeding in the brain; subdural is when blood gathers inside the dura mater; epidural is when blood gathers outside the dura mater


dura matter


outermost of 3 layers surrounding the brain


chronic vs. accute hematomas


slow bleeding and build-up vs. rapid bleeding


ICP


inter-cranial pressure


electrophysiology


measurements of the electrical activity of neurons, particularly action potential activity; powerful method for studying brain-behavior correlates


lateral inhibition


the capacity of an excited neuron to reduce the activity of its neighbors


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


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)


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


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


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)


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


Hemianopsia


whole half of a hemisphere (left or right) can�t be seen; causes include stroke, tumor, trauma


Scotoma


common small deficit, small visual field cut in specific location; everyone has one: blind spot, where optic nerve innervates the retina


"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


"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


Superior Temporal Sulcus


responsible for biological motion (dots = walking 'man'); is anterior to MT, sits squarely between dorsal and ventral streams