NeuroLab Ephys Exam

bioelectric signaling requirements

semipermeable membranes with channels and pumps that allow the internal enviroment of the cell to interact with the external environment

types of charged ions

potassium, sodium, chloride, and organic ions

electrical noise

when current is able to leak away from its source and make its way to the amplifier

sources of electrical noise

fluorescent lights, cell phones, radios, computers (and components)

what is being observed with ephys

voltage fluctuations

what kind of amplifiers are needed

high resistance amplifiers

Ohm’s law

voltage = current * resistance

what is the current through the amplifier

1 nanoAmp

most common ways of preventing noise

insulating wires, grounding

what is grounding

providing a low-resistance pathway for stray current to pass through

electrode

electrical conductor used to pick up electrical signal

amplifier

increase the voltage of the input signal for visualization and quantitative analysis

why use different amplifiers

biological signals differ not only in voltage amplitude but also their temporal pattern

low-pass filter

allows low-frequency voltage fluctuations through while attentuating high-frequency voltage fluctuations

high-pass filter

allows high-frequency voltage fluctuations through while attentuating low-frequency voltage fluctuations

band-pass filter

using both high- and low- pass filters

A/D converter

iWorx RA 834, changes continuous biological signal to discrete digital signal for analysis

what is the gel comprised of

electrolyte containing chloride ions (AgCl)

why use gel

increases the concudtivity of the skin/electrode interface

ion exchange at the skin surface

ions from the skin exchange with ions in the electrolyte gel, and the flow is picked up by the electrode

first amplifier that we use

C-ISO-256, 400x, high-pass: 0.05 Hz, low-pass: 25 or 2.5 kHz

second amplifer that we use

ETH-256 amplifier, x5

what is eeg used for

characterize sleep disorders, monitor anesthesia, assess levels of arousal and brain death

advantages of eeg over fmri

less expensive, no confinement of patients, high temporal resolution, measures neural activity directly

current sink

site where the EPSP is generated (where positive ions enter the cell)

current source

the flow of ions out of the cell, can be measured

eeg recording electrode senses

the mass activity of thousands of neurons

beta waves

eyes open, focused (13-40 Hz), desynchronized

alpha waves

eyes closed, relaxed (8-13 Hz), more synchronous

alpha block

transition from a synchronized to a desynchronized brain state

delta waves

high amplitude, synchronized waves in late non-REM sleep (1-3 Hz)

purpose of spectral analysis

quantify the composition of complex waveforms

fourier transformation

decomposes a complex waveform into its constituent sine waves and calculates how much each sine wave contributes to the overall waveform

power

the higher the amplitude of a particular sine wave, the more power it contributes to the shape of the overal signal

anterior tentacle and oral veil

posterior tentacle (rhinophore)

function of rhinophores

smelling/olfaction

seminal groove

genital aperture

function of seminal groove

sperm and egg transport

parapodium

function of parapodia

swimming

opaline gland

function of opaline gland

makes mucus to make ink more viscous and sticky

gill

purple gland

anus

foot

siphon

function of siphon

water jet

mantle shelf aperture

function of mantle shell aperture

covers gills

mantle and shell

buccal mass

function of buccal mass

where the aplysia determines if the food is edible

esophagus

crop

function of crop

stores food until food that has already been eaten is completely processed

anterior gizzard

function of anterior gizzard

where teeth are, grind up the food

hepatopancreas

intestines

ovotestes

function of ovotestes

where sperm and eggs are made

small hermaphroditic duct

accessory genital mass

components of accessory genital mass

winding gland, albumen gland, mucous gland

large hermaphroditic duct

spermatheca

if animal is sexually active, the spermatheca will be

dark, opaque

penis

gill

how much ink is released at each inking event

50% of remaining vesicles (similar to half-life)

opaline gland

green

buccal ganglia

blue

cerebral ganglia

orange

pleural ganglia

red

pedal ganglia

green

abdominal ganglia

pink top

branchial ganglion

pink bottom

genital ganglion

cerebral ganglia innervates

(tactile, sensory) mouth, anterior tentacles, eyes, rhinophores, penis

buccal ganglia innervates

(digestion) odontophore, buccal mass, pharynx, esophagus, crop, salivary gland, anterior gizzard

pedal ganglia innervates

(motion) parapodia, head, penis, foot

abdominal ganglia innervates

mantle shell, gill, siphon, heart, kidney, intestine, posterior gozzard, large and small hermaphroditic ducts, hepatopancreas, AGM, spermatheca, ovotestis

silent cell

no spontaneous spike rate

beating cell

rhythmic spontaneous spike rate

bursting cell

non-rhythmic spontaneous spike rate

main predator of aplysia

spiny lobster

passive defensive behaviors

bad taste, camouflage

active, involuntary defensive behaviors

gill withdrawal reflex

active, voluntary defensive behaviors

ink secretion (purple gland), opaline secretion (mucus secretion)

probe test should produce what voltage

20 mV

resistance of probe resistor

20 MOhm

dorsal surface

left connective

right connective

branchial nerve

genital-perichardial nerve

siphon nerve