Tweak Your Technique
Electrophysiology 101
August 19, 2011
Kevin Lee
What can be studied with
electrophysiology?
• Single channel behaviour
– in expression systems: HEK293, CHO’s, X. Laevis
oocytes
• Intrinsic properties of excitable cells
– neurons, myocytes
• Synaptic transmission
– neuromuscular junction, neuronal synapses
The hippocampus
Field recordings
LTP/LTD
Whole-cell Recordings
Patch-Recording Methods
Whole-cell recordings
Current-clamp vs Voltage-clamp
“EPSP”
“EPSC”
Whole-cell recordings
Current-clamp vs Voltage-clamp
Voltage-clamp
mEPSCs (minis)
mEPSC amplitude reflects synaptic AMPAR content
Beique et al. (PNAS, 2006)
mEPSCs (minis)
mEPSC frequency can reflect:
- total number of synapses
- presynaptic function
Beique et al. (PNAS, 2006)
Release probability (Pr) of glutamate
Changes in frequency of mEPSCs is generally
believed to reflect changes in Pr.
“Paired-Pulse” electrical stimulation can also
provide information about Pr.
Beique et al. (PNAS, 2006)
What about Molecular interventions?
Biolistic transfection of cortical neurons in
organotypic slices
Beique & Andrade (J. Physiol, 2002; cover photo)
Biolistic transfection of cortical neurons in
organotypic slices
Biolistic transfection of cortical neurons in
organotypic slices
Cull-Candy et al. (Science STKE, 2004)
Barria & Malinow (Neuron, 2002)
Drawbacks to electrical stimulation:
- Difficult to isolate individual synaptic events
- Spatial Parameters left unknown
2P-Uncaging of MNI-Glutamate
2P-Uncaging of MNI-Glutamate
Uncaging of MNI-Glu
activates both AMPA and
NMDA receptors
High spatial resolution of
glutamate uncaging
Béïque et al., PNAS 2006
Simultaneous Glutamate Uncaging and Calcium Imaging
Single Synapse Ca2+ Imaging
Uncage
1
2
Time 
1
2
Fundamental dendritic properties probed by glutamate
uncaging and calcium imaging
Losonczy & Magee (Neuron, 2006)
Fundamental dendritic properties probed by glutamate
uncaging and calcium imaging
Losonczy & Magee (Neuron, 2006)
Experimental Wizardry to Envy
Kravitz et al. (Nature, 2009)
Experimental Wizardry to Envy
Kravitz et al. (Nature, 2009)
Multiple Simultaneous Recordings in Slices
Olah et al. (Nature, 2009)
The
End