Term
| Transduction & Action Potential |
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Definition
For touch/pain & prioprioceptive (deep tissue) receptors:
The receptor is part of the sensory neuron and can lead to action potential directly in the sensory neuron |
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Term
| Vision + Hearing receptors |
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Definition
the sensory receptors produce graded potentials only (depolarization for smell, taste, hearing, hyperpolarization for vision) which lead to EPSP causing an action potential in an associated (secondary) neuron.
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Term
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Definition
olfactory hair cell -> mitral neuron
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Term
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Definition
cochlear hair cell -> spiral neuron
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Term
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Definition
photoreceptor/bipolar cell -> ganglion neuron
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Term
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Definition
| A major sensory way- station to the cortex |
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Term
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Definition
| ascending sensory pathways are generally crossed(from one side of the body to the other side of the brain-or "contralateral" projections) but level of crossing vanes |
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Term
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Definition
crosses at the thalamic level, while pain path crosses down in the spinal cord.
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Term
| Percent of crossed fibers alsovaries |
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Definition
-right visual field projects exclusively to left hemisphere
-auditory fibers are about 2/3 contralateral and 1/2 ipsilateral. |
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Term
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Definition
| transduced by 3 types of free nerve endings (2 have unmyelinated fibers, 1 is myelinated). |
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Term
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Definition
pain receptor (noxious receptor)
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Term
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Definition
transduced by 4 types of receptors.
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Term
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Definition
| (vibration, large receptive field, fast adapting) |
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Term
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Definition
(stretch, large border, slow adapting)
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Term
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Definition
| (touch, small receptive field, fast adapting) |
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Term
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Definition
| (touch, small receptive field, slow adapting) |
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Term
| Cutaneous (skin) stimulus intensity |
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Definition
| coded via differential receptor thresholds, which means as the intensity of skin stimulation increases (temp, pressure, pain), more receptors are depolarized. (This principle holds for all sensory systems). |
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Term
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Definition
| (skin receptor, projects up dorsal (spinal) column, to the somatosensory thalamic nucleus (ventro-posterior nucleus; VPN), and then primary somatosensory cortex (SM -1)). This path crosses midline just before passing through the thalamus. |
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Term
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Definition
| (point to point) mapping in somatosensory cortex. |
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Term
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Definition
| proportional to sensory receptor populations thus highly enervated areas (fingers, lips) have greater representation in SM cortex (think of the “homunculus” with enlarged hands and lips). |
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Term
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Definition
| you can increase cortical representation via stimulation/training, decrease representation with deprivation or loss of digit/hand etc. |
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Term
| laminar/columnar organization |
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Definition
| Lamina are formed early by migrating neurons (which stop in layers). |
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Term
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Definition
| (free nerve endings (receptors), project to anterolateral pathway (crosses midline in spinal cord), reticular formation, periaquaductal grey, and different target regions of cortex (frontal, cingulate, primary somatosensory)). |
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Term
| perceptual representations of pain |
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Definition
| cognitive (frontal), emotional (cingulate), location (SM cortex). |
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Term
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Definition
| In response to pain, in the descending pain pathway, periaquaductal grey releases opiates, which causes descending neurons of the raphe nucleus to inhibit incoming pain signals via serotonergic inhibition. This is different from periphery, where serotonin is an excitatory pain neurotransmitter. |
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Term
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Definition
| the aperture, formed by theiris, that allows light to enter the eye. |
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Term
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Definition
| a structure in the eye that helps focus an image on retina. |
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Term
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Definition
| the receptive surface inside the eye that contains pnotoceptors and other neurons |
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Term
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Definition
| the central portion of the retina, packed w/ the most photoreceptors and therefore the center of our gaze |
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Term
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Definition
| cronial nerve II the collection of garglion cell axons that extend from the retina to the optic chiasm |
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Term
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Definition
| controlled by muscles to focus images on the back of the retina. |
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Term
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Definition
| where the optic nerve passes through the retina (our brain “fills in” this perceptual hole for us). |
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Term
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Definition
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Term
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Definition
| composed of photoreceptors (rods and cones), bi-polar cells and ganglion cells. |
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Term
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Definition
| are actually in back so that light passes through ganglion and bi-polar layers to reach them. |
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Term
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Definition
-in auditory system
-sena their axons into the auditory nerve |
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Term
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Definition
- in retina
-send their axons into the optic nerve |
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Term
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Definition
| (The optic nerve is actually a bundle of ganglion cell axons). |
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Term
| mechanics of phototransduction |
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Definition
| light photon hits opsin molecule, conformation change results in reduced cGMP, this closes Na+ ion channels, and hyperpolarizes photoreceptor. Hyperpolarization reduces transmitter output to bi-polar cell. |
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Term
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Definition
| hyperpolarize in response to stimulation, |
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Term
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Definition
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Term
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Definition
| in response to stimulation, while other sensory receptors depolarize – we do not know why). Nevertheless, hyperpolarization gets translated into depolarization by the bipolar cell, and into an action potential by the ganglion cell). |
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Term
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Definition
in the retinal periphery, use rhodopsin, encode blue/green light, are low acuity, and are used for night vision.
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Term
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Definition
| concentrated in the fovea (which is why acuity is very high there), use 3 different opsins, and prefer 3 different light wavelengths (blue, green, red). |
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Term
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Definition
| people are missing 1 kind of cone, and can only process light wavelengths with the cones they have. Some light frequencies are hard for them to discriminate. |
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Term
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Definition
| characterized by frequency (another visual meaning for this word), which represents the level of detail [think “high frequency = high definition TV (lots of info per inch),” while “low frequency” = simple, low-detail]. |
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Term
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Definition
| (black/ white = high contrast, shades of grey = low contrast). |
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Term
| Primary visual cortex (V1 |
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Definition
| laminar and columnar organization, just like SM cortex and auditory cortex. |
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Term
| Structures of the visual system |
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Definition
| respond to increasingly complex bits of information as one moves upwards. |
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Term
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Definition
| “on/off,” ganglion cells respond to “fields,” and LGN and V1 neurons start to respond to specific orientations, motion, colors, etc. |
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Term
| principle of sensory systems |
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Definition
| principle of shifting from “point to point” representation, to more of a “Gestalt” representation (objects, faces) |
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Term
| re-organization of visual cortex |
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Definition
| Individuals who are blind from an early age & use Braille to read |
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Term
| Visual cortical reading areas |
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Definition
| (next to Wernicke) respond to visual text in the sighted, but to Braille (somatosensory) text in the congenitally blind. |
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Term
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Definition
| cardiac and skeletal, contracts and relaxes in short bursts. |
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Term
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Definition
enervates the gut and other organs, involuntary, more sustained contractions.
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Term
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Definition
| occurs due to stimulation at the neuromuscular junction, where excitatory acetylcholine leads to changes in ion channels (potentials), and the “sliding” of actin/myosin protein molecules over each other to contract muscle. |
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Term
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Definition
controls all voluntary movement.
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Term
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Definition
is an involuntary “stabilizing” or motor feedback system, and operates through input/feedback to cerebellum and basal ganglia, which projects back to motor cortex through VAN (other inputs as well, see below).
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Term
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Definition
(sympathetic, parasympathetic, enteric) controls smooth (involuntary) muscle (& also striated cardiac muscle).
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Term
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Definition
sensory feedback regarding posture and muscle status (tells the brain where our limbs are in space) – projects mainly to cerebellum and basal ganglia, (which
feed back to motor cortex via VAN thalamic nucleus); some input through VPN to SM cortex. |
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Term
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Definition
| which controls voluntary muscles. This pathway is fairly direct (for speed), and includes some of the longest axons in the body. |
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Term
| extra-pyramidal motor pathway, |
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Definition
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SM input from VPN to SM to motor;
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Proprioceptive input mainly to cerebellum and basal ganglia, then to VAN and
back to motor;
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Vestibular input through PLN to auditory cortex and cerebellum to motor;
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Auditory and visual orienting through MGN and LGN to A1/V1 and back to
motor.
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Term
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Definition
| specific motor impulses generated within the spinal horn to specific stimuli (don’t pass up to the brain). Short latency, probably for survival. |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| (generally reflects sleep/wake patterns, with activity during wake). |
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Term
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Definition
| (to adjust an internal rhythm to an outside source such as sunlight). |
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Term
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Definition
| to experience a circadian rhythm driven internally, independent from any external cues). |
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Term
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Definition
| Specialized ganglion cells in the retina (use melanopsin), project via retinohypothalamic tract to the supra chiasmatic nucleus (SCN) in the hypothalamus, which signals the pineal gland to secrete melatonin. |
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Term
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Definition
| (visual pathway) does NOT eliminate input to the retinohypothalamic tract. When blindness is caused by anomalies at the level of optic nerve or higher (with retina intact), then the circadian system is still functional. |
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Term
| Time isolation experiment |
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Definition
| assessing sleep/wake patterns in humans under “free running” conditions. The human body adjusts to an “internal” day period slightly LONGER than 24 hr under these conditions. |
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Term
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Definition
levels (from the pineal) peak during sleep period (~4AM).
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Term
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Definition
also surges at night, reflecting growth (in children) and cellular repair
in adults, during sleep.
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Term
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Definition
| electroencephaolograph, recording from multiple surface (skin) electrodes. Used in sleep labs to identify sleep states and diagnose sleep disorders. |
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Term
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Definition
1 – SWS (slow wave sleep), light sleep, alpha rhythm
2 – SWS, light sleep, sleep spindles
3 and 4 – SWS, deep sleep, delta waves; memory consolidation
REM – rapid eye movements, follows stage 1 sleep (not 4), desynchronized, paralysis, dreaming |
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Term
Neural mechanisms of sleep/wake:
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Definition
•Inhibitory (sleep) GABA networks in cortex (driven by basal forebrain)
•Excitatory (wake) Ach networks in cortex (driven by “reticular activating system” including pons, raphe nucleus, locus coeruleus)
•REM driven by pons, cortical excitation (similar to wake) with motor paralysis (pons to spinal cord) |
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Term
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Definition
(sleep walking; stage 3+4 SWS)
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Term
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Definition
(partially in REM but feel awake, realistic possibly alien dreams; REM to wake)
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Term
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Definition
(brief paralysis coming out of REM; REM to wake)
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Term
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Definition
| (abnormal wake-to-REM transition) |
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