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Nat Neurosci. 2014 Mar;17(3):383-90. doi: 10.1038/nn.3646. Epub 2014 Feb 2.

NMDA spikes enhance action potential generation during sensory input.

Author information

1
1] Florey Institute, University of Melbourne, Melbourne, Victoria, Australia. [2] Physiologisches Institut, Universit├Ąt Bern, Bern, Switzerland. [3] NeuroCure Cluster of Excellence, Humboldt University, Berlin, Germany.
2
Bioengineering Department, California Institute of Technology, Pasadena, California, USA.
3
Department of Chemistry, University of Oxford, Oxford, UK.
4
Department of Physiology, Development and Neuroscience, Physiological Laboratory, University of Cambridge, Cambridge, UK.
5
1] Physiologisches Institut, Universit├Ąt Bern, Bern, Switzerland. [2] NeuroCure Cluster of Excellence, Humboldt University, Berlin, Germany.

Abstract

Recent evidence in vitro suggests that the tuft dendrites of pyramidal neurons are capable of evoking local NMDA receptor-dependent electrogenesis, so-called NMDA spikes. However, it has so far proved difficult to demonstrate their existence in vivo. Moreover, it is not clear whether NMDA spikes are relevant to the output of pyramidal neurons. We found that local NMDA spikes occurred in tuft dendrites of layer 2/3 pyramidal neurons both spontaneously and following sensory input, and had a large influence on the number of output action potentials. Using two-photon activation of an intracellular caged NMDA receptor antagonist (tc-MK801), we found that isolated NMDA spikes typically occurred in multiple branches simultaneously and that sensory stimulation substantially increased their probability. Our results demonstrate that NMDA receptors have a vital role in coupling the tuft region of the layer 2/3 pyramidal neuron to the cell body, enhancing the effectiveness of layer 1 input.

PMID:
24487231
DOI:
10.1038/nn.3646
[Indexed for MEDLINE]

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