Neuroscience Techniques Flashcards
A problem with single cell preparations is…?
There are no synaptic connections intact
Tissue preparations include…?
Single cell, brain, spinal cord, invertebrate, in vivo and implanted electrode
Preparations including the brainstem and spinal cord are advantageous because…?
Synaptic connections can be stimulated and recorded
Gathering a brain slice involves 3 main steps, what are they?
Brain is removed quickly, kept oxygenated, and sliced using a vibroslice
How long can brain tissue remain alive for once removed and sliced?
5-10 hours
Intacellular recordings uses what type of electrode?
A sharp glass electrode (30-150 MOhms)
With regards to intracellular recordings, what is a ground?
The internal voltage is compared with the ground, which is outside
What preparations can use intracellular recording?
Single cell, brain slices and in vivo
What can be added via intracellular electrodes?
Dyes, including biocytin and neurobiotin
What is the advantage of applying dye to the preparations?
The tissue can be processed and visualised using light microscopy to determine electrophysiology and neuroanatomy
What type of electrode is used for extra cellular recordings?
An external low resistance electrode (<20 MOhms)
What is intracellular recordings used to measure?
Resting membrane potentials, action potentials, firing rate and synaptic potentials
What is extra cellular recordings used to measure?
Action potential firing rates, synaptic potentials of large neurone populations
What preparations can use extra cellular recordings?
Brain slices, in vivo and intact nerve
What type of electrode is used to apply drugs to the preparation? And what is this process called?
A multi-barrelled electrode via microiontophoresis
What are the clinical implications of microiontophoresis?
Identifying the best treatments for epilepsy
What recording technique uses a low resistance patch electrode (5 MOhms)?
Patch clamp recording
Regarding patch clamp recording, what must for in order for recordings to be made?
A high resistance Gigaohm seal
How is a Gigaohm seal formed?
The electrode is placed against the membrane and gentle suction is applied
Patch clamp recordings can be done on which tissue preparations?
Single cell and brain slices
What is a microscopic current?
The current flowing through the single isolated channel in a patch clamp recording
Voltage clamp recordings allows for two processes, these are…?
Measuring the current through the ion channel, and controlling the membrane potential
What electrodes are used in voltage clamp recordings?
Two sharp electrodes
What preparations allow voltage clamp recordings?
Single cells, but these must be large, such as xenopus oocytes
What is the advantage of applying mRNA sequences to oocytes via voltage clamp recordings?
mRNA sequences of ion channels allow the channel expression within the cell; used to understand channel function in disease, eg epilepsy
