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Cortical Membrane Potential Dynamics and Laminar Firing during Object Motion.

Harvey MA, Valentiniene S, Roland PE - Front Syst Neurosci (2009)

Bottom Line: Complex dynamics evolved including feedback from areas 19/21, the computation of a spatially restricted pre-depolarization (SRP), and firing in the direction of cortical motion prior to the mapping of the bar.After 350 ms, the representations of the bar (peak firing and peak VSD signal) in areas 19/21 and 17/18 moved over the cortex in phase.The dynamics comprise putative mechanisms for automatic saliency of novel moving objects, coherent mapping of moving objects across layers and areas, and planning of catch-up saccades.

View Article: PubMed Central - PubMed

Affiliation: Brain Research, Department of Neuroscience, Karolinska Institute Stockholm, Sweden.

ABSTRACT
When an object is introduced moving in the visual field of view, the object maps with different delays in each of the six cortical layers in many visual areas by mechanisms that are poorly understood. We combined voltage sensitive dye (VSD) recordings with laminar recordings of action potentials in visual areas 17, 18, 19 and 21 in ferrets exposed to stationary and moving bars. At the area 17/18 border a moving bar first elicited an ON response in layer 4 and then ON responses in supragranular and infragranular layers, identical to a stationary bar. Shortly after, the moving bar mapped as moving synchronous peak firing across layers. Complex dynamics evolved including feedback from areas 19/21, the computation of a spatially restricted pre-depolarization (SRP), and firing in the direction of cortical motion prior to the mapping of the bar. After 350 ms, the representations of the bar (peak firing and peak VSD signal) in areas 19/21 and 17/18 moved over the cortex in phase. The dynamics comprise putative mechanisms for automatic saliency of novel moving objects, coherent mapping of moving objects across layers and areas, and planning of catch-up saccades.

No MeSH data available.


Statistically significant laminar onsets of MUA at three cortical sites. At each site along the 17/18 border, the statistically defined onset of firing for the five leads corresponding the supragranular (S) layers, the three leads corresponding to the granular (G) layers and the five leads corresponding to the infragranular (G) layers were pooled to give a mean S, G, and I onset for each animal. The mean and SEM for all 11 animals are shown. Note that these values were taken from both upward and downward movement conditions, i.e. the data points at 540 μm are taken from recordings 540 μm lateral to the center for upward bar motion and 540 μm medial to the center for downward bar motion.
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Figure 3: Statistically significant laminar onsets of MUA at three cortical sites. At each site along the 17/18 border, the statistically defined onset of firing for the five leads corresponding the supragranular (S) layers, the three leads corresponding to the granular (G) layers and the five leads corresponding to the infragranular (G) layers were pooled to give a mean S, G, and I onset for each animal. The mean and SEM for all 11 animals are shown. Note that these values were taken from both upward and downward movement conditions, i.e. the data points at 540 μm are taken from recordings 540 μm lateral to the center for upward bar motion and 540 μm medial to the center for downward bar motion.

Mentions: In the motion conditions, the luminance bar moved with constant velocity of 25° s−1 up or down the vertical meridian of the FOV. Just like the stationary bar, the bar introduced moving from the CFOV elicited an ON response at the cortical site representing the CFOV (Figure 2D). This initial ON response was indistinguishable from the ON response evoked by the stationary bar (Figure 2C). As for the stationary bar, the onset of significant firing occurred first in the G layer (mean = 31 ms, SEM = 2 ms, N = 11). This was significantly, p = 0.002, earlier than the onset of significant firing in the S layers (mean = 50 ms, SEM = 7 ms, N = 11) as well as significantly, p = 0.00015, earlier than the onset of firing in the I layers (mean = 55 ms, SEM = 6 ms, N = 11) (Figure 3 Top). The MUA had only two peaks, an ON response peaking at 46.5 ms, SEM = 1.5 ms, N = 11 in the S layers, at 49.2 ms, SEM = 1.5 ms, N = 11, in the G layer and at 52.8 ms, SEM = 1.2 ms, N = 11 in the I layers. The second peak occurred at 141 ms, SEM = 6.6 ms, N = 11 in the I layers at 135 ms, SEM = 6.7 ms, N = 11 in the G layer and at 142 ms, SEM = 7.6 ms, N = 11 in the I layers. For the ON response peaks there were no statistical differences in their timing between layers (p > 0.1 for comparison of S and I layers versus the G layer). Neither were there any differences between ON peaks for the stationary bar and the bar moving from the CFOV (p > 0.2 in each case). So from the laminar MUA, the ON response to the moving bar was not different from the ON response to the stationary bar at the CFOV. (Figures 2C,D).


Cortical Membrane Potential Dynamics and Laminar Firing during Object Motion.

Harvey MA, Valentiniene S, Roland PE - Front Syst Neurosci (2009)

Statistically significant laminar onsets of MUA at three cortical sites. At each site along the 17/18 border, the statistically defined onset of firing for the five leads corresponding the supragranular (S) layers, the three leads corresponding to the granular (G) layers and the five leads corresponding to the infragranular (G) layers were pooled to give a mean S, G, and I onset for each animal. The mean and SEM for all 11 animals are shown. Note that these values were taken from both upward and downward movement conditions, i.e. the data points at 540 μm are taken from recordings 540 μm lateral to the center for upward bar motion and 540 μm medial to the center for downward bar motion.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2742661&req=5

Figure 3: Statistically significant laminar onsets of MUA at three cortical sites. At each site along the 17/18 border, the statistically defined onset of firing for the five leads corresponding the supragranular (S) layers, the three leads corresponding to the granular (G) layers and the five leads corresponding to the infragranular (G) layers were pooled to give a mean S, G, and I onset for each animal. The mean and SEM for all 11 animals are shown. Note that these values were taken from both upward and downward movement conditions, i.e. the data points at 540 μm are taken from recordings 540 μm lateral to the center for upward bar motion and 540 μm medial to the center for downward bar motion.
Mentions: In the motion conditions, the luminance bar moved with constant velocity of 25° s−1 up or down the vertical meridian of the FOV. Just like the stationary bar, the bar introduced moving from the CFOV elicited an ON response at the cortical site representing the CFOV (Figure 2D). This initial ON response was indistinguishable from the ON response evoked by the stationary bar (Figure 2C). As for the stationary bar, the onset of significant firing occurred first in the G layer (mean = 31 ms, SEM = 2 ms, N = 11). This was significantly, p = 0.002, earlier than the onset of significant firing in the S layers (mean = 50 ms, SEM = 7 ms, N = 11) as well as significantly, p = 0.00015, earlier than the onset of firing in the I layers (mean = 55 ms, SEM = 6 ms, N = 11) (Figure 3 Top). The MUA had only two peaks, an ON response peaking at 46.5 ms, SEM = 1.5 ms, N = 11 in the S layers, at 49.2 ms, SEM = 1.5 ms, N = 11, in the G layer and at 52.8 ms, SEM = 1.2 ms, N = 11 in the I layers. The second peak occurred at 141 ms, SEM = 6.6 ms, N = 11 in the I layers at 135 ms, SEM = 6.7 ms, N = 11 in the G layer and at 142 ms, SEM = 7.6 ms, N = 11 in the I layers. For the ON response peaks there were no statistical differences in their timing between layers (p > 0.1 for comparison of S and I layers versus the G layer). Neither were there any differences between ON peaks for the stationary bar and the bar moving from the CFOV (p > 0.2 in each case). So from the laminar MUA, the ON response to the moving bar was not different from the ON response to the stationary bar at the CFOV. (Figures 2C,D).

Bottom Line: Complex dynamics evolved including feedback from areas 19/21, the computation of a spatially restricted pre-depolarization (SRP), and firing in the direction of cortical motion prior to the mapping of the bar.After 350 ms, the representations of the bar (peak firing and peak VSD signal) in areas 19/21 and 17/18 moved over the cortex in phase.The dynamics comprise putative mechanisms for automatic saliency of novel moving objects, coherent mapping of moving objects across layers and areas, and planning of catch-up saccades.

View Article: PubMed Central - PubMed

Affiliation: Brain Research, Department of Neuroscience, Karolinska Institute Stockholm, Sweden.

ABSTRACT
When an object is introduced moving in the visual field of view, the object maps with different delays in each of the six cortical layers in many visual areas by mechanisms that are poorly understood. We combined voltage sensitive dye (VSD) recordings with laminar recordings of action potentials in visual areas 17, 18, 19 and 21 in ferrets exposed to stationary and moving bars. At the area 17/18 border a moving bar first elicited an ON response in layer 4 and then ON responses in supragranular and infragranular layers, identical to a stationary bar. Shortly after, the moving bar mapped as moving synchronous peak firing across layers. Complex dynamics evolved including feedback from areas 19/21, the computation of a spatially restricted pre-depolarization (SRP), and firing in the direction of cortical motion prior to the mapping of the bar. After 350 ms, the representations of the bar (peak firing and peak VSD signal) in areas 19/21 and 17/18 moved over the cortex in phase. The dynamics comprise putative mechanisms for automatic saliency of novel moving objects, coherent mapping of moving objects across layers and areas, and planning of catch-up saccades.

No MeSH data available.