The Journal of Neuroscience, February 20, 2008, 28(8):1871-1881; doi:10.1523/JNEUROSCI.3948-07.2008
Previous Article | Next Article 
Behavioral/Systems/Cognitive
Recurrent Synaptic Input and the Timing of Gamma-Frequency-Modulated Firing of Pyramidal Cells during Neocortical "UP" States
Kenji Morita,1
Rita Kalra,2
Kazuyuki Aihara,3,4 and
Hugh P. C. Robinson2
1RIKEN Brain Science Institute, Wako 351-0198, Japan, 2Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3EG, United Kingdom, 3Institute of Industrial Science, University of Tokyo, Meguro, Tokyo 153-8505, Japan, and 4Aihara Complexity Modelling Project, Exploratory Research for Advanced Technology, Japan Science and Technology Corporation, Shibuya, Tokyo 151-0064, Japan
Correspondence should be addressed to Dr. Hugh P. C. Robinson, Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK. Email: hpcr{at}cam.ac.uk
Gamma (
) oscillation, a hallmark of cortical activity during sensory processing and cognition, occurs during persistent, self-sustained activity or "UP" states, which are thought to be maintained by recurrent synaptic inputs to pyramidal cells. During neocortical "UP" states, excitatory regular spiking (RS) (pyramidal) cells and inhibitory fast spiking (FS) (basket) cells fire with distinct phase distributions relative to the
oscillation in the local field potential. Evidence suggests that
-modulated RS
FS input serves to synchronize the interneurons and hence to generate
-modulated FS
RS drive. How RS
RS recurrent input shapes both self-sustained activity and
-modulated phasic firing, although, is unclear. Here, we investigate this by reconstructing
-modulated synaptic input to RS cells using the conductance injection (dynamic clamp) technique in cortical slices. We find that, to show lifelike
-modulated firing, RS cells require strongly
-modulated, low-latency inhibitory inputs from FS cells but little or no
-modulation from recurrent RS
RS connections. We suggest that this demodulation of recurrent excitation, compared with inhibition, reflects several possible effects, including distributed propagation delays and integration of excitation over wider areas of cortex, and maximizes the capacity for representing information by the timing of recurrent excitation.
Key words: conductance injection; dynamic clamp; local field potential; regular-spiking; fast-spiking; synchronization
Received June 22, 2007;
revised Nov. 30, 2007;
accepted Dec. 23, 2007.
Correspondence should be addressed to Dr. Hugh P. C. Robinson, Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK. Email: hpcr{at}cam.ac.uk
This article has been cited by other articles:

|
 |

|
 |
 
T. Tateno and H.P.C. Robinson
Integration of Broadband Conductance Input in Rat Somatosensory Cortical Inhibitory Interneurons: An Inhibition-Controlled Switch Between Intrinsic and Input-Driven Spiking in Fast-Spiking Cells
J Neurophysiol,
February 1, 2009;
101(2):
1056 - 1072.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
M. A. Smith and A. Kohn
Spatial and Temporal Scales of Neuronal Correlation in Primary Visual Cortex
J. Neurosci.,
November 26, 2008;
28(48):
12591 - 12603.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. Borgers, S. Epstein, and N. J. Kopell
Gamma oscillations mediate stimulus competition and attentional selection in a cortical network model
PNAS,
November 18, 2008;
105(46):
18023 - 18028.
[Abstract]
[Full Text]
[PDF]
|
 |
|