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The functional asymmetry of auditory cortex is reflected in the organization of local cortical circuits.

Oviedo HV, Bureau I, Svoboda K, Zador AM - Nat. Neurosci. (2010)

Bottom Line: By contrast, we found that local connections along the tonotopic axis differed from those along the isofrequency axis: some input pathways to L3 (but not L2) arose predominantly out-of-column.In vivo cell-attached recordings revealed differences between the sound-responsiveness of neurons in L2 and L3.Our results are consistent with the hypothesis that auditory cortical microcircuitry is specialized to the one-dimensional representation of frequency in the auditory cortex.

View Article: PubMed Central - PubMed

Affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA.

ABSTRACT
The primary auditory cortex (A1) is organized tonotopically, with neurons sensitive to high and low frequencies arranged in a rostro-caudal gradient. We used laser scanning photostimulation in acute slices to study the organization of local excitatory connections onto layers 2 and 3 (L2/3) of the mouse A1. Consistent with the organization of other cortical regions, synaptic inputs along the isofrequency axis (orthogonal to the tonotopic axis) arose predominantly within a column. By contrast, we found that local connections along the tonotopic axis differed from those along the isofrequency axis: some input pathways to L3 (but not L2) arose predominantly out-of-column. In vivo cell-attached recordings revealed differences between the sound-responsiveness of neurons in L2 and L3. Our results are consistent with the hypothesis that auditory cortical microcircuitry is specialized to the one-dimensional representation of frequency in the auditory cortex.

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Synaptic input correlation between pairs of auditory cortical neuronsPlot shows the relationship between the correlations of input maps in pairs of cells in the same slice as a function of their intersomatic horizontal distance. We compared population correlation along the tonotopic and isofrequency axes. The gray line is the exponential fit (0.37 * exp(−x/159)). Square points showing the correlation of maps obtained for the same cell represent the theoretical upper limit of correlation given the experimental variability.
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Figure 5: Synaptic input correlation between pairs of auditory cortical neuronsPlot shows the relationship between the correlations of input maps in pairs of cells in the same slice as a function of their intersomatic horizontal distance. We compared population correlation along the tonotopic and isofrequency axes. The gray line is the exponential fit (0.37 * exp(−x/159)). Square points showing the correlation of maps obtained for the same cell represent the theoretical upper limit of correlation given the experimental variability.

Mentions: The pairwise map correlation as a function of intersomatic distance is shown in Fig 5. For both tonotopic and isofrequency slices, the correlation was largest for neurons closest together and declined with distance. The mean correlation between the nearest (< 100 µm) pairs was 0.30±0.02 and 0.34±0.04 for the tonotopic and isofrequency slices (respectively), and was lower than that between more distant (>100 µm) pairs (0.2±0.04 and 0.18±0.04 for the tonotopic and isofrequency slices.) To quantify the decrease in correlation with distance, we fitted the data with a simple exponential c = 0.37 * exp(−x/159), where x is the intersomatic distance (in micrometers). Thus nearby neurons are not very correlated, and the correlation falls off rapidly, with a decay of about 159 µm.


The functional asymmetry of auditory cortex is reflected in the organization of local cortical circuits.

Oviedo HV, Bureau I, Svoboda K, Zador AM - Nat. Neurosci. (2010)

Synaptic input correlation between pairs of auditory cortical neuronsPlot shows the relationship between the correlations of input maps in pairs of cells in the same slice as a function of their intersomatic horizontal distance. We compared population correlation along the tonotopic and isofrequency axes. The gray line is the exponential fit (0.37 * exp(−x/159)). Square points showing the correlation of maps obtained for the same cell represent the theoretical upper limit of correlation given the experimental variability.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3140463&req=5

Figure 5: Synaptic input correlation between pairs of auditory cortical neuronsPlot shows the relationship between the correlations of input maps in pairs of cells in the same slice as a function of their intersomatic horizontal distance. We compared population correlation along the tonotopic and isofrequency axes. The gray line is the exponential fit (0.37 * exp(−x/159)). Square points showing the correlation of maps obtained for the same cell represent the theoretical upper limit of correlation given the experimental variability.
Mentions: The pairwise map correlation as a function of intersomatic distance is shown in Fig 5. For both tonotopic and isofrequency slices, the correlation was largest for neurons closest together and declined with distance. The mean correlation between the nearest (< 100 µm) pairs was 0.30±0.02 and 0.34±0.04 for the tonotopic and isofrequency slices (respectively), and was lower than that between more distant (>100 µm) pairs (0.2±0.04 and 0.18±0.04 for the tonotopic and isofrequency slices.) To quantify the decrease in correlation with distance, we fitted the data with a simple exponential c = 0.37 * exp(−x/159), where x is the intersomatic distance (in micrometers). Thus nearby neurons are not very correlated, and the correlation falls off rapidly, with a decay of about 159 µm.

Bottom Line: By contrast, we found that local connections along the tonotopic axis differed from those along the isofrequency axis: some input pathways to L3 (but not L2) arose predominantly out-of-column.In vivo cell-attached recordings revealed differences between the sound-responsiveness of neurons in L2 and L3.Our results are consistent with the hypothesis that auditory cortical microcircuitry is specialized to the one-dimensional representation of frequency in the auditory cortex.

View Article: PubMed Central - PubMed

Affiliation: Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA.

ABSTRACT
The primary auditory cortex (A1) is organized tonotopically, with neurons sensitive to high and low frequencies arranged in a rostro-caudal gradient. We used laser scanning photostimulation in acute slices to study the organization of local excitatory connections onto layers 2 and 3 (L2/3) of the mouse A1. Consistent with the organization of other cortical regions, synaptic inputs along the isofrequency axis (orthogonal to the tonotopic axis) arose predominantly within a column. By contrast, we found that local connections along the tonotopic axis differed from those along the isofrequency axis: some input pathways to L3 (but not L2) arose predominantly out-of-column. In vivo cell-attached recordings revealed differences between the sound-responsiveness of neurons in L2 and L3. Our results are consistent with the hypothesis that auditory cortical microcircuitry is specialized to the one-dimensional representation of frequency in the auditory cortex.

Show MeSH