Term
|
Definition
| oldest and most common sensory system. |
|
|
Term
|
Definition
| Gustation, Olfaction, Chemoreception |
|
|
Term
|
Definition
| Saltiness, sourness, sweetness, bitterness, and umami |
|
|
Term
|
Definition
| poisonous substances are often bitter |
|
|
Term
|
Definition
| tongue, mouth, palate, pharynx, and epiglottis |
|
|
Term
| Area of Sweetness sensitivity on tongue |
|
Definition
|
|
Term
| Area of Bitterness sensitivity on tongue |
|
Definition
|
|
Term
| Area of Saltiness and Sourness sensitivity on tongue |
|
Definition
|
|
Term
|
Definition
| vallate, fungiform, foliate |
|
|
Term
|
Definition
| possess clusters of taste receptor cells called taste buds. MICROVILLI extend to taste pore |
|
|
Term
| Tastant binding causes... |
|
Definition
|
|
Term
| Taste: 3 thigs Receptor potential does |
|
Definition
| causes voltage-gated Ca2+ channels to open; neurotransmitter release occurs; gustatory axons are stimulated |
|
|
Term
| Gustatory axons excited by... |
|
Definition
| 4 basic tastes, but there is a bias (tuning) |
|
|
Term
|
Definition
| process where environmental stimuli cause an electrical response in a sensory receptor |
|
|
Term
| Salt and sour tastants occur by.. |
|
Definition
| passing directly through ion channels |
|
|
Term
| Just sour tastants occur by... |
|
Definition
| binding to and blocking ion channels |
|
|
Term
| Bitter, sweet and umami tastants occur by... |
|
Definition
| binding to G-protein-coupled receptors that activate second messengers which in turn open ion channels |
|
|
Term
| Saltiness taste transduction |
|
Definition
| salt-sensitive taste cells: special Na+ selective channel (blocked by amiloride). Depolarization causes voltage-gated Na+ and Ca2+ channels to open |
|
|
Term
| Sourness taste transduction |
|
Definition
| sourness is due to high acidity (low pH). Protons (H+) causative agents of acidity and sourness--can pass through amiloride Na+ channels and block K+ channels |
|
|
Term
| Bitterness taste transduction |
|
Definition
| T1R(bind to sweet tastants and amino acids-umami) and T2R(30+) family taste receptor genes. |
|
|
Term
| Bitterness: G-protein coupled receptors |
|
Definition
bitter, sweet and umami receptors all use the same second messenger pathway.
G-protein activates Phospholipase C which increases production of inositol triphosphate (IP3)--IP3 activates a Na+ channel; triggers release of intracellular Ca2+ (depolarization causes opening of voltage-gated Ca2+ channels |
|
|
Term
| Sweetness taste transduction |
|
Definition
| tastes both natural and artificial. Receptors T1R2+T1R3 |
|
|
Term
|
Definition
| detect amino acids (eg MSG). T1R1+T1R3. There are sweet-, bitter- and umami-specific taste cells |
|
|
Term
|
Definition
| Gustatory Nucleus, Ventral posterior medial nucleus, Primary gustatory cortex(Brodmann's area 36) |
|
|
Term
| Taste pathway: gustatory nucleus |
|
Definition
| point where taste axons bundle and synapse |
|
|
Term
| Taste pathway: primary gustatory cortex |
|
Definition
| receives axons from VPM taste neurons |
|
|
Term
| taste: labeled line hypothesis |
|
Definition
| individual taste receptor cells for each stimuli |
|
|
Term
|
Definition
| responses of large numbers of broadly tuned neurons are integrated |
|
|
Term
|
Definition
| olfactory receptor cells, supporting cells, and basal cell |
|
|
Term
|
Definition
| constitute olfactory nerve |
|
|
Term
|
Definition
| a thin sheet of bone through which small clusters of axons penetrate, coursing to the olfactory bulb |
|
|
Term
|
Definition
|
|
Term
| Surface area of olfactory epithelium: human v. dog |
|
Definition
Human: 10 cm2
Dog: 170 cm2 |
|
|
Term
|
Definition
| oderant molecule binds to receptor, g-protein activated |
|
|
Term
| olfactory: g-protein activation (5 steps) |
|
Definition
1. Activation of Adenylyl cyclase -> formation of cAMP
2. cAMP binds to cAMP-gated cation channels
3. Influx of Ca2+ and Na+
4. Opens Ca2+ activated Cl-channels
5. Current flow and membrane depolarization |
|
|
Term
| termination of olfactory responses |
|
Definition
| odorants diffuse away; enzymes break them down; cAMP may activate signalling pathways which end transduction |
|
|
Term
|
Definition
| decreased response despite continued presence of stimulus |
|
|
Term
| 3 central olfactory pathways |
|
Definition
| Olfactory bulb, olfactory cortex, and Neocortex |
|
|
Term
|
Definition
|
|
Term
|
Definition
| receives input from only one type of olfactory receptor cell |
|
|
Term
|
Definition
| reached directly by neurons originating in olfactory bulb. Only example of direct sensory input to cortex (not neocortex) |
|
|
Term
|
Definition
| reached by a pathway that synapses in the medial dorsal nucleus of the thalamus |
|
|
Term
| 3 Spatial and Temporal representations of olfactory information |
|
Definition
| Olfactory population coding, Olfactory maps (sensory maps), Temporal Coding in the olfactory system |
|
|
Term
|
Definition
| study of light rays and their interactions with the environment: reflection, absorption, refraction |
|
|
Term
|
Definition
| bouncing of light rays off a surface |
|
|
Term
|
Definition
| transfer of light energy to a particle or surface |
|
|
Term
|
Definition
| bending of light rays from one medium to another. due to speed of light differing in two media |
|
|
Term
| Gross anatomy of the eye (5) |
|
Definition
1. Pupil: opening where light enters the eye
2. Sclera: White of the eye
3. Iris: Gives color to eyes
4. Cornea: Glassy transparent external surface of the eye
5. Optic nerve: bundle of axons from the retina |
|
|
Term
|
Definition
| region where optic nerve fibers exit retina. blood vessels originate from this structure and arc towards the macula. |
|
|
Term
|
Definition
| area 2mm in diameter where retina is thinnest |
|
|
Term
|
Definition
| change shape to adjust focus. divides eyes into two compartments(Aqueous humor in anterior chamber; Jelly-like vitreous humor in posterior chamber). ciliary muscles and ligaments suspend lens |
|
|
Term
|
Definition
1. Connections between retina and brain stem neurons that control muscle around pupil; consensual process(both pupils)
2. Continuously adjusting to different ambient light levels
3. Pupil similar to the aperture of a camera(reduces 'blurring' of distant objects) |
|
|
Term
|
Definition
| amount of space viewed by the retina when the eye is fixated straight ahead |
|
|
Term
|
Definition
| distances across the retina described in degrees |
|
|
Term
|
Definition
| ability to distinguish two nearby points--dependent on density of photoreceptor cells |
|
|
Term
|
Definition
| cells that convert light energy into neural activity. Rods and cones |
|
|
Term
|
Definition
| Bipolar cells -> ganglion cells |
|
|
Term
| Direct Horizontal pathways |
|
Definition
| Horizontal cells -> Amacrine cells |
|
|
Term
| 4 main regions of photoreceptors |
|
Definition
outer segment
inner segment
cell body
synaptic terminal |
|
|
Term
|
Definition
| Higher ratio of rods to cones; higher ratio of photoreceptors to ganglion cells; more sensitive to light |
|
|
Term
|
Definition
| all cones(no rods); high area of visual acuity--1:1 ratio of photoreceptors to ganglion cells.. cones densely packed |
|
|
Term
| Phototransduction in rods |
|
Definition
| responsible for night vision-depolarized in the dark: "Darkcurrent". Hyperpolarized in the light |
|
|
Term
| Phototransduction in rods Rhodopsin |
|
Definition
retinal embedded in opsin molecule
-retinal derived from Vit A
-stimulation with light causes a conformational change in retinal->activates opsin('bleached') molecule |
|
|
Term
| Rod phototransduction in dark |
|
Definition
Na+ channels open
-gated by a second messenger molecule: cGMP
-cGMP continually produced by guanylyl cyclase |
|
|
Term
| Rod phototransduction in light |
|
Definition
Na+ channels close
-opsin activates G-protein(transducin); transducin activates PDE which converts cGMP to GMP; levels of cGMP drop |
|
|
Term
| Rod phototransduction: amplification |
|
Definition
many G-proteins are activated by each opsin and each PDE enzyme breaks down more than one cGMP
-allows for high sensitivity of photoreceptors
-one photon can stimulate a rod photoreceptor |
|
|
Term
| Cone phototransduction: 3 cone types |
|
Definition
|
|
Term
| Cone phototransduction: Red cone type |
|
Definition
| long wavelength sensitive |
|
|
Term
| Cone phototransduction: Green cone type |
|
Definition
| medium wavelength sensitive |
|
|
Term
| Cone phototransduction: Blue cone type |
|
Definition
| short wavelength sensitive |
|
|
Term
|
Definition
| predicted 3 cone types- trichromacy theory of color vision |
|
|
Term
|
Definition
| no S-cones in the fovea; short wavelength light is refracted to a greater extent; results in focal point being in front of the retina |
|
|
Term
|
Definition
Dilation of pupils
regeneration of unbleached rhodopsin
adjustment of functional circuitry |
|
|
Term
| Dark and Light Adaptation |
|
Definition
| All-cone daytime vision--> All-rod nighttime vision |
|
|
Term
|
Definition
| area of the retina that, when stimulated with light, changes a cell's membrane potential |
|
|
Term
| Center-surround receptive field |
|
Definition
center and surround are antagonistic(response of one region opposes the response of the other).
-bipolar cells show this RF arrangement
-RF organization passed on to retinal ganglion cells |
|
|
Term
|
Definition
| have transmitter-gated ion channels that are excited by glutamate; glutamate depolarizes Off bipolar cells |
|
|
Term
|
Definition
| have G-protein coupled receptors that are inhibited by glutamate; glutamate hyperpolarizes On bipolar cells |
|
|
Term
| Bipolar cells generate... |
|
Definition
|
|
Term
| Center-surround circuitry: center receptive field |
|
Definition
| direct path from cone to bipolar cell |
|
|
Term
| Center-surround circuitry: surround receptive field |
|
Definition
| indirect pathway: cone in surround > horizontal cell > cone at center of receptive field |
|
|
Term
| 3 Types of ganglion cells |
|
Definition
| M-type (mango), P-type (parvo), nonM-nonP |
|
|
Term
|
Definition
| relatively large; comprise 5% of GC population. have large receptive fields; high action potential velocity |
|
|
Term
|
Definition
relatively small; comprise of 90% of GC population. have small receptive field; slower action potential velocity
-some are color oppulent |
|
|
Term
|
Definition
not well characterized; comprise 5% of GC population
-some are color oppulent |
|
|
Term
| Calcium's role in Light Adaptation (3) |
|
Definition
1. Ca2+ enters cell in the dark(admitted via Na+ channels); inhibits enzyme that makes cGMP> [cGMP]decreases
2. In the light, production of cGMP is less inhibited as closing of channels prevents Ca2+ entry; [cGMP] increases and Na+ channels will open even in light
3. Photoreceptors sensitive to relative changes in light level |
|
|
Term
|
Definition
| biological rhythms, including sleep and wakefulness |
|
|
Term
|
Definition
| size of the pupil; certain types of eye movement |
|
|
Term
|
Definition
| Orients the eyes in response to new stimuli |
|
|
Term
| Lateral Geniculate Nucleaus (LGN): receptive fields |
|
Definition
| receptive fields of LGN neurons are virtually identical to the ganglion cells that provide input to them |
|
|
Term
|
Definition
-retinal ganglion cells axons are NOT the main source of synaptic input to LGN
-primary visual cortex provides 80% of the synaptic input to LGN |
|
|
Term
| Retinotopy (Retinotopic Maps) |
|
Definition
-Maps of the visual field onto a target structure(retina, LGN, superior colliculus, striate cortex)
-adjacent cells in retina project to adjacent neurons in LGN, which in turn project to adjacent cells in striate cortex |
|
|
Term
| Lamination of Striate Cortex |
|
Definition
-Layers IVC: spiny stellate cells--spine covered dendrites
-Layers III, IVB, V, VI: pyramidal cells--spines; thick apical dendrite |
|
|
Term
|
Definition
| lack spines; all cortical layers; forms local connections |
|
|
Term
| Striate Cortex Inputs: Mangocellular neurons |
|
Definition
|
|
Term
| Striate Cortex Inputs: Parvocellular neurons |
|
Definition
|
|
Term
| Striate Cortex Inputs: Koniocellular neurons |
|
Definition
| Bypasses layer IV to make synapses in layers II and III |
|
|
Term
| Superficial Layers: Layer IVC |
|
Definition
| innervates layers II and III |
|
|
Term
| Superficial Layers: Layer III |
|
Definition
| many cells are binocular (receive input from both eyes), although input from one eye still dominant |
|
|
Term
| Striate Cortex Outputs: Layers II, III, and IVB |
|
Definition
| Project to other cortical areas |
|
|
Term
| Striate Cortex Outputs: Layer V |
|
Definition
| Projects to superior colliculus and pons |
|
|
Term
| Striate Cortex Outputs: Layer VI |
|
Definition
|
|
Term
|
Definition
| mitochondrial enzyme used for cell metabolism--it is possible to stain tissue that is rich in the enzyme |
|
|
Term
|
Definition
visualized by cytochrome oxidase staining in cross sections of the striate cortex
-receive direct input from koniocellular LGN neurons |
|
|
Term
| Parallel Pathways: Mangocellular |
|
Definition
| neurons have binocular receptive fields; orientation selective; some are direction sensitive; not wavelength sensitive; large receptive fields--suggest suitability for detecting object motion |
|
|
Term
| Parallel Pathways: Parvo-interblob |
|
Definition
| neurons have binocular RFs; orientation selective; not direction or wavelength sensitive; small receptive fields--suggest suitability for detecting fine object shape |
|
|
Term
|
Definition
| monocular receptive fields; typically center-surround RF; RFs are color-opponent--suitable for color processing |
|
|
Term
|
Definition
| neuron fires action potentials in response to moving bar of light only if it moves in a particular direction |
|
|
Term
| Receptive field: 3 Simple cells |
|
Definition
| Binocular; Orientation-selective; Elongated on-off region with antagonistic flanks responds to optimally oriented bar of light |
|
|
Term
|
Definition
| (where pathway) analysis of visual motion and the visual control of action--a continuation of the magnocellular pathway |
|
|
Term
|
Definition
| (what pathway) perception of the visual world and the recognition of objects--a continuation of the parvocellular(inter-blob) and koniocellular(blob) pathways |
|
|
Term
|
Definition
| (temporal lobe) most cells: direction-selective; respond more to the motion of objects than their shape |
|
|
Term
|
Definition
| (receives direct input from MT) cells respond to 'optic flow' |
|
|
Term
|
Definition
| Many cells have complex receptive fields and color selectivity |
|
|
Term
|
Definition
| clinical syndrome in humans--caused by damage to the area V4; partial or complete loss of color vision |
|
|
Term
|
Definition
-Major output of V4
-Respond to a wide variety of colors and abstract shapes
-some evidence of position invariance
-evidence for 'face-selective' neurons in IT--region within IT referred to as the fusiform face area (FFA) |
|
|
Term
|
Definition
| hypothetical neuron that represents any complex and specific concept or object |
|
|
