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Two-photon Calcium Imaging in Neuronal Dendrites in Brain Slices
Published on: March 15, 2018
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Dendritic calcium spikes are clearly detectable at the cortical surface
Mototaka Suzuki1, Matthew E Larkum2
1NeuroCure Cluster of Excellence, Department of Biology, Humboldt University, Charitéplatz 1, 10117, Berlin, Germany. mototaka@gmail.com.
Nature Communications
|August 19, 2017
Summary
Dendritic calcium spikes, previously linked to cognition, are detectable in surface brain recordings like EEG. This study reveals their unexpected waveform and significant contribution to surface potentials.
Area of Science:
- Neuroscience
- Electrophysiology
Background:
- Cortical surface recordings (EEG, ECoG) primarily assume detection of synaptic activity.
- Non-synaptic events' contribution to surface potentials is less understood.
Purpose of the Study:
- To investigate the detectability of dendritic calcium spikes in cortical surface potentials.
- To elucidate the contribution of dendritic calcium spikes to EEG signals.
Main Methods:
- Developed an optogenetic, non-synaptic method to evoke dendritic calcium spikes in vivo in rat somatosensory cortex.
- Recorded cortical surface potentials during optogenetically and sensory-evoked dendritic calcium spikes.
Main Results:
- Optogenetically evoked dendritic calcium spikes were clearly detectable with a distinct waveform near the cortical surface.
- Sensory-evoked dendritic calcium spikes were also detectable, with amplitudes comparable to synaptic contributions.
- Dendritic calcium spikes significantly impact surface potentials.
Conclusions:
- Dendritic calcium spikes are a significant component of surface EEG recordings.
- Existing surface recording data may contain information about cognitively relevant dendritic activity.
- Revises the understanding of what surface recordings measure in brain activity.
