-
Across Fiber Coding
- When a stimulus is coded through the RATIO of response across multiple cells.
- i.e. temperature, hot respond more to hot cold to cold, etc.
-
Convergence (Summation)
When MULTIPLE pre-synaptic cells all communicate to ONE post-synaptic cell
-
Divergence
When ONE pre-synaptic cell communicates to many post-synaptic cells.
-
Receptive Field
Set of receptors whose activity influences the activity of target cell.
-
Excitatory Center-Inhibitory Surround
Type of Receptive Field: stimulating center increases target response, non-center decreases it.
-
Topological
Type of map that preserves spatial relationships (as along a sensory surface).
-
Magnification Factor
- In cortex, disproportionate enlargement of the representation of a sensory area of low convergence.
- (Cortical cells with small Receptive Fields fill a disproportionally large area of the visual projection areas)
-
Module
An area of the brain specialized for processing one particular type of information
-
The Binding Problem
- The problem posed by having several modules, and yet perceiving wholes.
- i.e. red square
-
Retina
Rear layers of neurons in the eyeball
-
Visual Receptors (Rods and Cones)
Cells that respond to light
-
Rods
Visual receptor that are (HIGH) convergent, sensitive to motion and low light, mainly in periphery.
-
Cones
Visual receptor that connect few to 1 (LOW Convergent), sensitive to color and detail, dispersed plus concentrated in center.
-
Fovea
Central area of cone receptors, connected 1:1 for highest acuity.
-
Bipolar Cells
(Postsynaptic to Receptors) Next cell in pathway, spontaneous firing, graded potentials, release excitatory NT.
-
Horizontal Cells
Inter-neurons that modify reaction of bipolars, implicated in color opponency.
-
Ganglions
(Postsynaptic to Bipolars) Next cell in pathway, shows action potentials, release excitatory NT. The axon of this cell forms the Optic Nerve.
-
Optic Nerve
Ganglions cell axon form this.
-
Optic Disc
Place where optic nerve leaves eye for brain, also called "blind spot"
-
Amacrines
- Inter-neurons that modify reaction of optic disc (ganglions), implicated in contrast effects.
- Graded Potentials, mostly Inhibitory NT, modify interface of Bipolars and Ganglions
-
Dim
Level of light that results in greatest release of NT from Receptors
-
Bright
Level of light that results in greatest release of NT from Bipolars
-
Acuity
High-detail discrimination, as from low convergence, that retains info on differences from rods and cones.
-
Sensitivity
High likelihood of detection, as from high convergence that crosses next cell's threshold.
-
Lateral Inhibition
- Cell activity resulting in release of inhibitory NT to cells orthogonal to info pathway
- - Functions mainly to exaggerate differences
-
Simultaneous Contrast
Illusion created by lateral inhibition that alters perception of central grey depending on its surrounding.
-
Uni-directional
Direction of inhibition in direction-sensitive motion circuit.
-
Lateral Geniculate Nucleus (LGN)
Nucleus in Thalamus that processes most visual information from eye.
-
Column
In cortex, set of cells, in 6 layers, that all respond to the same preferred stimulus.
-
Hyper column
In cortex, set of cells that all have the same Receptive Fields and include set of orientation columns & blobs.
-
Retinotopic Map
Topological map that preserves spatial relationships found on retina
-
V1 (Striate Cortex)
Primary projection area for vision in occipital lobe of cortex.
-
Parvocellular Pathway
Visual pathway specialized for color and detail, that "flows" along bottom of cortex.
-
Temporal Pathway
Parvocellular Pathway is also call what because it terminates in the lobe of this cortex.
-
Who/What Pathway
Parvocellular Pathway also calls what because it conveys information that helps you to identify a stimulus or individual
-
X Ganglions
Small ganglion cells that begin parvocellualr pathways, with small Receptive Fields and sustained response.
-
Magnocellular Pathway
Visual pathway specialized for motion and localization, "flows" along top part of cortex.
-
Parietal Pathway
Magnocellular Pathway also calls what because it Terminates in this lobe of the cortex
-
Where/How Pathway
Parietal Pathway also calls what because it Conveys info that helps locate and interact with stimuli
-
Y Ganglions
Large ganglion cells that begin Magnocellular pathway, with large Receptive Fields and transient response.
-
Superior Colliculus
Nucleus in Midbrain in Magnocellualar path, processes some visual (esp motion) info from eye
-
Blindsight
Though visual cortex damaged and no visual experience, mid-brain enables some visual localization.
-
Trichromatic Color Vision
Color coding per ratio of activity of 3 cone types responding to 3 overlapping ranges of frequencies.
-
Color Opponency
Recoding of Trichromatic Color Vision, via lateral inhibition from Horizontal cells, into red/green and blue/yellow
-
Opponent Cells
LGN or Ganglions with R+G-, G+R-, B+Y-, or Y+B- receptive fields
-
Color Constancy
V4 mediated processes that enables identification of color under different light conditions (AKA "retinex theory")
-
Simple Cells
Cells in V1 that respond to line, or gradient, oriented in particular direction
-
Complex Cells
Cells in V2 that best response to moving lines of particular direction
-
Spatial Frequencies
Number of dark/light changes per degree of visual angle
-
High Frequencies
Frequency gradients that V1 cells in Parvo path are most sensitive to
-
Low Frequency
Frequency gradients that V1 cells in Magno path are most sensitive to
-
Inferior Temporal (IT)
End of parvo pathway, includes cells that prefer hand, face, or other complex stimulus.
-
Prosopagnosia
Deficit from damage to Fusiform Gyrus, patient cannot recognize familiar faces.
-
Medial Temporal
Cortical area with direction-sensitive cells, responds best to stimulus moving across retina.
-
Medial Superior Temporal
Cortical area with optic-flow detectors, respond best to contraction/expansion of whole scene.
-
Superior Temporal Sulcus (STS)
Area in anterior Temporal lobe that response to Biological Motion
-
Disparity Detectors
In V2 or MT, cells that respond to degrees of difference between location of an image on 2 retina
-
Canonical Cells
Cells in higher parietal cortex that respond to the affordances of an object
-
Mirror Cells
Parietal cells (also found in Premotor Cortex) that respond to seeing self or other perform task.
-
Tympanic Membrane
Membrane vibrated by air molecules moving down Auditory Canal
-
Ossicles
Three tiny bones (Malleus/Hammer, Incus/Anvil, Stapes/Stirrup) linked into lever system, amplify vibrations of Tympanic Membrane
-
Oval Window
Membrane vibrated by the third ossicle bone, initiating vibration of (Endolymph) Cochlear Fluid.
-
Endolymph
Thick, incompressible, potassium-rich fluid that fills cochlea.
-
Cochlea
snail-like Coiled, three chambered tube [top (Scala Vestibuli), mid (S. Media), bottom (S. Tympani)] in Inner Ear which contains Organ of Corti
-
Organ of Corti
Section of central chamber of Cochlea where Receptor Cells are found
-
Basilar Membrane
Membrane that runs along floor of Organ of Corti, moves up and down.
-
Tectorial Membrane
Membrane that runs along the roof of Organ of Corti, moves forward and back.
-
Hair Cells
Auditory receptor cells that are deformed between Basilar and Tectorial Membrane
-
Cilia
Tiny "hairs" extending from hair cells whose deformation initiates transduction.
-
K+ (Potassium)
Ion that enters receptor, decreasing its polarity (Audition)
-
Ca++
Ion that enters the receptor, causing chain reaction that results in release of excitatory NT (Glutamate)
-
Glutamate
NT released by auditory receptors
-
Graded Potential
Type of change in polarity in auditory receptors
-
Spiral Ganglions
Cells to which auditory Receptors communicate, whose axons exit to brain.
-
Action Potential
Type of change in polarity in spiral ganglions.
-
Place Coding
Relative levels of activity across diffferentially-resonsating basilar membrane code frequency.
-
Temporal coding
Rate of oscillation of Bas. Membrane codes frequency per rate of Auditory Nerve Firing
-
Refractory Period
Time during which Auditory Nerve Fibers cannot fire next action potential.
-
Volley Principle
Since each cell can only fire 1/1000 sec, must work together at alt. intervals.
-
Phase Locked
Ganglions involved in Volley Principle can only all fire at the same phase (e.g.) peak of input wave
-
Intensity Differences
- Differences used for localization, caused by "head shadow" attenuating high frequencies.
- Sound at ear closer to source is slightly more intense (louder) than at other ear, because of Head Shadow.
- -Works best for higher frequencies, since these most likely to be absorbed by head
-
Phase Differences
- Differences used for localization, comparing peak and trough of lower frequencies reaching both ears
- - Peak = oscillating molecules most condensed
- -Trough = oscillating molecules most rarefied - widely spread out
-
Timing Differences
Differences used for localization, per race of left vs. right. Onset signals to superior olive.
-
Inner Hair Cells
Receptor cells that show divergent connectivity, for detail freq discrimination.
-
Outer Hair Cells
Receptor cells that show convergent connectivity, for loudness discrimination.
-
Auditory Nerve
Axons of spiral ganglion in auditory path form this nerve
-
8th Cranial Nerve
Auditory Nerve is part of this cranial nerve
-
Cochlear Nucleus
Next synapse in Medulla, beginning of separate information pathways.
-
Primary Like Cell
Cells in Cochlear Nucleus that duplicated incoming signal
-
Tonotopic Map
Primary Like Cells helps generate what kind of map that represents low>high frequency across cell array
-
Onset Cell
Cell in Cochlear Nucleus that transforms incoming signal into a transient burst.
-
Buildup Cell
Cell in Cochlear Nucleus that transforms incoming signal into one of graded, increasing amplitude.
-
Monoaural
When information from only one ear is involved.
-
Binaural
When information from both ears is combined, good for localization as in superior olive.
-
Superior Olive
Next auditory site (after cochlea nucleus), also in Medulla, repsonsible for Orienting Reflex
-
Inferior Colliculus
Next auditory site (after superior olive), in MIDBRAIN, where info is integrated with visual at nearby site
-
Medial Geniculate Nucleus (MGN)
Next auditory site (after inferior colliculus), in Thalamus, site of among other things, A1
-
A1
Primary Projection Area for Audition, along Lateral Sulcus of Temporal Cortex
-
A2
- Secondary auditory area in cortex
- Most respond best to complex sounds (familiar noises, speech sounds)
-
Wernicke's Area
Area with critical role in comprehension of speech, in left hemisphere
-
Music
Type of complex auditory input processed by higher auditory centers in right hemisphere.
-
Hair Cells
Type of receptor cells in Vestibular System
-
K+
Which Ion, when not/allowed to enter cell, changes receptors polarity
-
Spontaneous Firing Rate
Changes in velocity & orientation alter this kind of firing rate.
-
Otolith Organ
- Where receptors respond to head tilt via gravity induced deformation by crystals
- "Ear Stones"
-
Semi-Circular Canals
Three fluid filled tubes that detect changes in angular acceleration
-
Motion Sickness
Effect when visual and/or motor feedback is inconsistant with vestibular info
-
8th Cranial Nerve
Which Cranial nerve shared with audition
-
Free Nerve Endings
- Class of receptors that respond to temperature, pain, itch, and hair follicle movement
- -respond to change in Temperature (Thermoreceptors) and pain & itch (Nociceptors)
-
Nociceptors
Receptors in Free Nerve Endings that respond to "noxious" (potentially damaging) stimuli
-
Encapsulated Endings
Class of receptors that respond to touch and internal movement
-
Proprioception
Detection of internal movement of muscles and organs
-
Action Potentials
Type of response by above type of receptors (encapsulated endings)
-
Selective Adaptation
Process by which one type of receptor is fatigues, showing its role in coding
-
Ventral Posterior Nucleus (VPN)
Nucleus of Thalamus in somatosensory pathway
-
Spinal Thalamic Pathway
Path for pain and temperature info to brain, crossing over in Spinal Cord
-
Medial Lemniscal Pathway
Pathway for touch and internal motion info to brain, crossing over in brainstem
-
Medial Lemniscal
Pathway tending to be mylinated
-
Brown-Sequard Syndrome
- When damage to one side of spine results in different losses on ipsilateral vs contralateral sides
- -reduction/loss of touch and position sense on the ipsi-lateral (right) side below the point of injury
- -reduction/loss of temperature and pain detection on the contra-lateral (left) side below the point of injury
-
Post Central Gyrus
Location of primary projection area for somatosensory info (S1)
-
Penfield Map
Name of topological map of body surface found Post Central Gyrus
-
Hands/Mouth/ Tongue
Disproportionally fill Penfield Map.
-
Substance P
NT released by pain receptors and other cells in pain pathway
-
Gate Theory
Theory concerning top down blocking of pain info entering brain
-
Periaqueductal Grey Area
Midbrain Area that is probaby the source of pain info blocking
-
Endorphins
"Endogenous morphines" released by Periaqueductal Grey Area
-
Inhibitory Interneuron
Type of interneuron in spine that responds to endorphin.
-
Naloxone
Opiate antagonist that reduces analgesic effects of morphine and acupuncture
-
Striate (Skeletal) Muscles
Type of muscle, made of parallel fibers, attached by tendons to bones.
-
Flexors
One type of Striate muscle, that moves bone towards body, in atagonistic pair with extensors
-
Extensors
One type of Striate muscle, that moves bone away from body, in atagonistic pair with flexors
-
Neuro-Muscular Junction
Where neuron releases NT that depolarizes muscle fiber cells > contraction
-
Acetylcholine (ACh)
NT released by effector neurons to contract muscles
-
Sarcomere
The contractile unit of a muscle fiber consisting of Myosin
-
Myosin
Thick protein filament with knobby bead-like Cross Bridges along it,
-
Actin
Thin braided protein filament, anchored to muscle, that myosin hook into and tighten
-
Spindle
a proprioceptor that detects passive stretch of a muscle, triggers Stretch Reflexx
-
Stretch Reflex
A mono-synaptic reflex that contracts muscle to counter passive stretch
-
Golgi Reflex
A reflex triggered by Tendon Organs detecting excessive contraction in muscle
-
Pain Withdrawal Reflex
A reflex triggered by pain detectors, rapidly removing skin from the source of pain
-
Scratch Reflex
A reflex involving an Oscillator Circuit producing a fixed-rate rhythm
-
Infant Reflexes
Reflexes, such as "rooting" or "grasping", found in newborns
-
Primary Motor Cortex
Area of cortex that includes body map, sends movement commands to Stem and Cord
-
Pre Central Gyrus
Location of the Primary Motor Cortex
-
Premotor Cortex
Anterior to the Primary Motor Cortex, active during preparation to move, receives esp from visual-spacial areas
-
Mirror Cells
Premotor Cortex includes cells that respond to image of self, or other, performing familiar manual tasks
-
Brocas Area
Lateral area that plans articulation, helps generate gramatical sentences (esp. in left hemisphere)
-
Supplementary Motor Cortex
Dorsal to Broca's Area, also active during prep, esp. for rapid movements, receives from Parietal
-
Corticospinal Pathways
Fast, crossing paths from Pyramids in cortex, esp. for precise control of peripheral moves
-
Red Nucleus (Tegmentum)
Cortico-Spinal Pathway stops at this Midbrain structure on the way from the Cortex to Medulla and Cord
-
Ventro-medial pathway
Mainly ipsilateral pathways for posture & gross movement of neck, shoulders & trunk
-
Cerebellum
"Little brain" involved esp in coordinated movement requiring aiming and timing
-
Ballistic
Movements that occur very rapidly and generally cannot be altered once begun
-
Purkinje Cells
"Telephone poles" in cerebellar cortex that help code time as distance
-
Parallel Fibers
"Wires" in Purkinje Cells whose action potentials release excitatory NT
-
Deep Nuclei
Central areas that receive from Purkinje Cells ("Telephone Poles") and send output to brain/chord
-
Basal Ganglia
Set of forebrain structures controlling posture, muscle tone, and smooth movement
-
Parkinson's Disease
Movement impairment, marked by rigidity, tremors, etc, for degeneration of Substantia Nigra
-
Substantia Nigra
Midbrain structure whose dopaminergic axons synapse in Basal Ganglia
-
L-DOPA
Precursor of dopamine, crosses blood-brain barrier, converted by neurons into dopamine
|
|