Neuro- Somatosensation

Front 1

Somatosensory systems

Back 1

get info into CNS
largely from outside world
but also from our bodies
info from muscles that tells about body position

Front 2

4 Attributes to a stimulus

Back 2

1. modality
2. intensity/strength
3. Timing/duration
4. Location

Front 3

Modaility defines

Back 3

a general class of stimulation
vision, hearing, touch, smell, taste
receptors respond to a specific type of energy from the physical world

Front 4

Sumodalities of vision, taste

Back 4

vision- color, form, depth
taste- salty, sweet, sour, bitter, umami

Front 5

Labled Line Code

Back 5

has to do w/ Modality
certain nerves carry specific types of sensory information

Muller-1826

Front 6

Intensity/Strength is signaled by

Population Code

Back 6

the freqency code (rate law)or number of APs
-more APs=higher intensity
more receptors stimulated w/ a higher intensity of a stimulus

Front 7

Timing or Duration

Back 7

defined as when the receptor starts and stops to respond

all receptors adapt. only differece is how quickly

Front 8

slowly adapting rec

rapidly adapting rec

Back 8

continues to fire APs

stops firing APs even w/ stim still there

Front 9

Location (5)

Back 9

receptor fields in dfft areas

especially important for vision and touch
less impt for taste/smell

Front 10

Receptor Fields form

Back 10

Topographic maps
-touch-somatotopic, vision-visuotopic
orderly 1-to-1 representation of rec in skin and location of RF in brain

Front 11

fine tactile descrimination have

Back 11

a higher density of receptors

Front 12

how are receptors classified?

fxn?

Back 12

by the type of stimulus to which they are most sensitive
transduction of phys stimulus into a neural stimulus
1. gen APs or
2. gen receptor potentials

Front 13

5 Types of Receptors

Back 13

1. photoreceptors
2. chemoreceptors
3. mechanoreceptors
4. thermoreceptors
5. Nociceptors-pain

Front 14

2 kinds of projections

Back 14

1. serial/heirarchal processing
2. parallel processing

Front 15

Serial or heirarchial processing produces what?

Back 15

complexity
neurons synapse in order, in series

Front 16

Parallel Processing

Back 16

2 pathways in series
used OFTEN in CNS b/c its FASTER
much more efficient than series

can be crossed or uncrossed

Front 17

convergence w/ receptor fields

Back 17

individually small RFs converge/synapse on a neuron that has a larger RF

Front 18

4 Perceptual Modalities

Back 18

1. Tactile
2. Proprioception
3. Thermal
4. Pain

Front 19

Tactile

Proprioception

Back 19

cutaneous, fine discrimination touch, fine detai
in muscles and joints. used to plan and make mvmts

Front 20

Mechanoreceptors

key distinction b/w rapidly and slowly adapting rec

Back 20

respond to mechanical deformation of skin

"where its located"

Front 21

4 Types of Cutaneous rec
capsulated

unencap

Back 21

Pacinian, Meis, Ruff, Merkel
pacinian, meisner, Ruffini

merkel-free nerve ending

Front 22

higher 2pt descrim accomplished by

Back 22

having a high density of rec in a small area
small RFs

large RF have a harder time w/ 2pt descrim

Front 23

most sensitive areas of your body have

Back 23

the greatest density of rec, smallest RFs

hands/face

Front 24

what breaks the 1-rec/1-type of touch rule?

Back 24

free nerve endings

Cornea only has free endings but can detect several dfft stimuli

Front 25

Superficial mechanorec

Deep mechanorec

Back 25

Meissner, Merkel

Pacinian, Ruffini

Front 26

Rapidly Adapting rec

Back 26

respond to just the onset

1. Superficial Meisner
2. deep Pacinian

Front 27

Slowly Adapting rec

Back 27

respond to sustained input

1. superficial Merkel
2. Deeper Rufini

Front 28

2Ms=superficial
P/R=deep

2corpuscles=rapidly adapting
2endings=slowly adapting

Back 28

meisner, merkel
pacinian, ruffini

meisner, pacinian
merkel, ruffini

Front 29

which receptors have small RF



fine tactile stimulation

Back 29

merkel, meisner

pacinian do NOT

detected by superficial receptors

Front 30

Proprioception


2 kinds of receptors

Back 30

detects stationary body position, mvmt of jts/musc, and can evaluate shape of objects
1. Muscle Spindles
2. Golgi Tendon Organs

Front 31

Muscle Spindles

Back 31

proprioception
long,thin, stretch rec in voluntary muscle
Parallel to muscle
synapse on excit MN in ventral horn

Front 32

what is a safety feature for overextension of muscle?

Back 32

muscle spindles synapse on excit MN in ventral horn

Front 33

Golgi Tendon Organ

Back 33

in series w/ muscle
in tendon, at end of extrafusal muscle fiber
sensitive to contraction

Front 34

Henry Head's theory

Back 34

dfft axons carry dfft aspects of touch

regrow at dfft times

Front 35

Erlanger and Gasser

light/descriminatory touch

pain/temp carried by

Back 35

first oscilloscopes

thicker axons-faster
A->C, I->IV
thinner axons-slower

Front 36

Parallel Processing in CNS

Back 36

fine touch and prop carried along same pathway
pain and temp carried along dfft pathway

Front 37

Dermatomes

Back 37

length-wise down the extremities and horizontally around the trunk

Front 38

DC/ML


2nd order neurons in..

Back 38

fine touch, prop
ascnd ipsilaterally
FC-lat, FG-med
nuc cuneatus, and nuc gracillus

Front 39

3rd order neurons in DCML pathway

ascend to....

Back 39

from VPM/VPL of thalmus
input from body-lateral
input from head-medial
via IC to Parietal Lobe

Front 40

Medial Lemniscus

Lateral Lemniscus

Back 40

deals w/ SS

Auditory information

Front 41

Facial input to DC/ML

Back 41

goes into principal nuc in the pons
from pons on, it travels w/ the ML

Front 42

Pain and Temperature Pathway

Back 42

Spinothalamic Tract STT

ascending in AL portion of lateral column
3rd order neuron projections go to many different places

Front 43

part of the AL pathway that goes to the thalmus

and..

Back 43

Spinothalamic Tract


spinoreticular formation
-impt in arousal
spinomesencephalic- midbrain
-may block relay of pain

Front 44

why is it difficult to interfere w/ pain pathways in the brain?

Back 44

more diffuse
3rd order neurons from thalmus go to not only SS cortex, but the parietal lobe, ant cingulate gyrus, and insular cortex

Front 45

damage to 1 side of the SC

damage to 1 side of the Medulla

Back 45

pain-contralat, touch/prop-ipsi

pain and touch/prop contralat

Front 46

Ventroposterior complex of thalmus

receives input from

Back 46

relay nucleus for touch
VPM-VPL really just one

ML and STT

Front 47

STT synapse on, CNV

ML synapses on

Back 47

VPM

VPL

Front 48

Criteria for defining areas of the Cortex

Back 48

1. staining-cytoarchitecture
2. representation of periphery
3. unique nerual properties
4. unique pattern of connections
5. unique deficits w/ damage

Front 49

Brodman's Areas in Parietal cortex for SS


from meial-->lateral

Back 49

3a, 3b, 1, and 2

4cytoarchitectural areas

feet-->head

Front 50

original consensus on SS cortex

Current View

Back 50

there were just 2 areas
SI and SII
8-10 SS cortex on each side
each brodman area has its own map

*1-to-1 result in cytoarchitecture to mapping

Front 51

why do we have multiple areas in the SS cortex?

Back 51

probably b/c of specialization
8-10dfft areas

Front 52

cutaneous input goes to areas?

Propioceptive input goes to areas?

Back 52

areas 3b and 1

areas 2 and 3a

Front 53

cortical areas consist of columns

Back 53

vertical collections of neurons that do the same thing

all correspond to same RF and probably same submodality

Front 54

Plasticity


immediate changes suggest
delayed changes suggest

Back 54

some parts of the brain maintain plasticity

unmasking of latent inputs, disinhibition
sprouting of connections