Single Unit recording and Action Flashcards
what is single unit recording
recording from single neurons using one of more microelectrodes
can you accurately tell if you measuring from one cell or not?
no (hard to tell)
how is single unit recording highly invasive?
- requires direct access to the brain
- trauma to scalp and skull
- risk of infection
- insertion of electrodes ay damage brain tissue
(usually done on animals)
when would SUR may be used on humans (it has a high threshold for use)
- already entering the brain for medical reasons (ex, epilepsy relief)
- potential to address severe disability (ex, quadraplegia)
animal experiments are acceptable if: (2) (opinion)
- suffering is minimized in all experiments
- human benefits are gained which could not be obtained using other methods
animal experiments are not acceptable because: (3) (opinion)
- it causes suffering to animals
- the benefits to human being are not proven
- any benefits to human being that animals testing does provide could be produced in other ways
how does the brain machine interface work?
- what is its purpose?
- 2 microelectrode arrays are implanted into the left motor cortex of the patients brain where their hair thin electrodes detect neuron signals
- neuron signals pass to connectors, attached to the skull
- amplified signals are fed to a brain machine interface which interprets them and passes them on to the arm
- interface operates robotic arm in real time
- to bi pass the damage in the brain stem or spinal cord and get the signals out in an effective way (they read out signals from motor cortex)
4 types of recording
- intracellular: voltage clamp/current clamp, patch clamp
- extracellular: single unit recording, multicellular recording, field potentials
- in vitro versus in vivo (vivo = animals)
- anaesthetized vs awake
recorded from inside a cell
- done in animals
- manipulated the single cell
intra cellular
this is recording electromagnetic fields near those neurons to get an idea of inhibitory
post synaptic potentials (but we will focus on action potentials)
field potentials
what does single unit and multi unit recordings record?
action potentials of individual cells
what are the challenges of recording AP fro single cells
- how to find the ‘right’ neurons
2. how does this neuron relate to the other 100 billion
you can use a ____ electrode or an _____
single, array (2mm apart with 100)
reading from each electrode, neurons will be closer
to some and further form others, but in general
each electrode will recieve signals from multiple neurons and
there will be alot of overlap
- array of electrodes
ex, implanted tetrode
in multi unit recording, 6 electrodes are sunk down into brain tissue, each electrode has ____ recording sites on it, so you are getting ___ recording simultaneously from the brain
–> when you see a spike what does this mean?
- 8, 64
- could be one neurons firing but it will show up in multiple electrode readings so you have sort the data - clustering