Limits...
Sub-Millisecond Firing Synchrony of Closely Neighboring Pyramidal Neurons in Hippocampal CA1 of Rats During Delayed Non-Matching to Sample Task.

Takahashi S, Sakurai Y - Front Neural Circuits (2009)

Bottom Line: The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison) and external (stimulus input and motor output) events during the task.However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently.We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information - as represented by the firing rate modulations - to downstream neurons.

View Article: PubMed Central - PubMed

Affiliation: Khoyama Center for Neuroscience, Faculty of Computer Science and Engineering, Kyoto Sangyo University Kyoto, Japan.

ABSTRACT
Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes), we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison) and external (stimulus input and motor output) events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information - as represented by the firing rate modulations - to downstream neurons.

No MeSH data available.


Related in: MedlinePlus

(A) Example of manipulation of spike trains generated from two neurons. Herein, S2 represents the number of windows in which two neurons fire simultaneously. A2 signifies the number of windows in which only one neuron fires. S(2-2) denotes the number of windows in which two neurons simultaneously fire. P2 is the occurrence probability of SSS between those two spike trains. (B) Example of manipulation of spike trains generated from three neurons. Here, S3 signifies the number of windows in which all three neurons simultaneously fire. A3 stands for the number of windows in which only one neuron fires. S(2-3) denotes the number of windows in which two or three neurons fire simultaneously. P3 represents the occurrence probability of SSS among those three spike trains. Each bar is one spike. Windows are partitioned by dashed lines. (C) The firing rate of SSSs between two Poisson spike trains is plotted as a function of the product of firing rate of those Poisson spike trains. The correlation coefficient, R, is 0.97. The solid line depicts a linear regression line. The regression coefficient is 1.0.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2742662&req=5

Figure 2: (A) Example of manipulation of spike trains generated from two neurons. Herein, S2 represents the number of windows in which two neurons fire simultaneously. A2 signifies the number of windows in which only one neuron fires. S(2-2) denotes the number of windows in which two neurons simultaneously fire. P2 is the occurrence probability of SSS between those two spike trains. (B) Example of manipulation of spike trains generated from three neurons. Here, S3 signifies the number of windows in which all three neurons simultaneously fire. A3 stands for the number of windows in which only one neuron fires. S(2-3) denotes the number of windows in which two or three neurons fire simultaneously. P3 represents the occurrence probability of SSS among those three spike trains. Each bar is one spike. Windows are partitioned by dashed lines. (C) The firing rate of SSSs between two Poisson spike trains is plotted as a function of the product of firing rate of those Poisson spike trains. The correlation coefficient, R, is 0.97. The solid line depicts a linear regression line. The regression coefficient is 1.0.

Mentions: In that equation, SN denotes the number of SSSs among N neurons. In other words, SN means the number of spikes generated simultaneously from all N neurons in a 1 ms window (see Figures 2A,B). AN denotes the number of asynchronous spikes with 1 ms precision. Asynchronous spikes are defined as spikes generated from only one of N neurons in a 1 ms window (see Figures 2A,B). S2-N represents the number of SSSs among two or more of N neurons.


Sub-Millisecond Firing Synchrony of Closely Neighboring Pyramidal Neurons in Hippocampal CA1 of Rats During Delayed Non-Matching to Sample Task.

Takahashi S, Sakurai Y - Front Neural Circuits (2009)

(A) Example of manipulation of spike trains generated from two neurons. Herein, S2 represents the number of windows in which two neurons fire simultaneously. A2 signifies the number of windows in which only one neuron fires. S(2-2) denotes the number of windows in which two neurons simultaneously fire. P2 is the occurrence probability of SSS between those two spike trains. (B) Example of manipulation of spike trains generated from three neurons. Here, S3 signifies the number of windows in which all three neurons simultaneously fire. A3 stands for the number of windows in which only one neuron fires. S(2-3) denotes the number of windows in which two or three neurons fire simultaneously. P3 represents the occurrence probability of SSS among those three spike trains. Each bar is one spike. Windows are partitioned by dashed lines. (C) The firing rate of SSSs between two Poisson spike trains is plotted as a function of the product of firing rate of those Poisson spike trains. The correlation coefficient, R, is 0.97. The solid line depicts a linear regression line. The regression coefficient is 1.0.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2742662&req=5

Figure 2: (A) Example of manipulation of spike trains generated from two neurons. Herein, S2 represents the number of windows in which two neurons fire simultaneously. A2 signifies the number of windows in which only one neuron fires. S(2-2) denotes the number of windows in which two neurons simultaneously fire. P2 is the occurrence probability of SSS between those two spike trains. (B) Example of manipulation of spike trains generated from three neurons. Here, S3 signifies the number of windows in which all three neurons simultaneously fire. A3 stands for the number of windows in which only one neuron fires. S(2-3) denotes the number of windows in which two or three neurons fire simultaneously. P3 represents the occurrence probability of SSS among those three spike trains. Each bar is one spike. Windows are partitioned by dashed lines. (C) The firing rate of SSSs between two Poisson spike trains is plotted as a function of the product of firing rate of those Poisson spike trains. The correlation coefficient, R, is 0.97. The solid line depicts a linear regression line. The regression coefficient is 1.0.
Mentions: In that equation, SN denotes the number of SSSs among N neurons. In other words, SN means the number of spikes generated simultaneously from all N neurons in a 1 ms window (see Figures 2A,B). AN denotes the number of asynchronous spikes with 1 ms precision. Asynchronous spikes are defined as spikes generated from only one of N neurons in a 1 ms window (see Figures 2A,B). S2-N represents the number of SSSs among two or more of N neurons.

Bottom Line: The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison) and external (stimulus input and motor output) events during the task.However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently.We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information - as represented by the firing rate modulations - to downstream neurons.

View Article: PubMed Central - PubMed

Affiliation: Khoyama Center for Neuroscience, Faculty of Computer Science and Engineering, Kyoto Sangyo University Kyoto, Japan.

ABSTRACT
Firing synchrony among neurons is thought to play functional roles in several brain regions. In theoretical analyses, firing synchrony among neurons within sub-millisecond precision is feasible to convey information. However, little is known about the occurrence and the functional significance of the sub-millisecond synchrony among closely neighboring neurons in the brain of behaving animals because of a technical issue: spikes simultaneously generated from closely neighboring neurons are overlapped in the extracellular space and are not easily separated. As described herein, using a unique spike sorting technique based on independent component analysis together with extracellular 12-channel multi-electrodes (dodecatrodes), we separated such overlapping spikes and investigated the firing synchrony among closely neighboring pyramidal neurons in the hippocampal CA1 of rats during a delayed non-matching to sample task. Results showed that closely neighboring pyramidal neurons in the hippocampal CA1 can co-fire with sub-millisecond precision. The synchrony generally co-occurred with the firing rate modulation in relation to both internal (retention and comparison) and external (stimulus input and motor output) events during the task. However, the synchrony occasionally occurred in relation to stimulus inputs even when rate modulation was clearly absent, suggesting that the synchrony is not simply accompanied with firing rate modulation and that the synchrony and the rate modulation might code similar information independently. We therefore conclude that the sub-millisecond firing synchrony in the hippocampus is an effective carrier for propagating information - as represented by the firing rate modulations - to downstream neurons.

No MeSH data available.


Related in: MedlinePlus