Figure 1. Laminar multielectrode recordings from border ownership-selective units in area V4.

(A) Top row shows set of border ownership stimuli. Black dotted outline represents the classical receptive field (cRF). Bottom row shows that the stimulus information in the cRF is identical for stimuli 1 and 2, and for stimuli 3 and 4. (B) Dot rasters showing responses to the stimuli in A from a border ownership-selective well-isolated unit. The symbol on the left indicates the preferred side of border ownership for the unit. Average spike rates in the stimulus window are indicated above the panels. (C, D) Similar to A and B, for a multiunit cluster recorded during a different penetration. (E) Cartoon showing the recording setup. A laminar multielectrode probe with 32 channels was lowered through a transparent artificial dura (AD), orthogonal relative to the cortical surface. (F) Laminar compartments (superficial; granular [input]; deep layers) were estimated using current source density (CSD) analysis. See text for definitions of the compartments and explanation of symbols. Distance from center of granular layer is shown along ordinate on the left, and the number of electrode contact on the right (higher numbers correspond to more superficial contacts). Black solid triangle indicates position of most superficial electrode contact on which multiunit activity was recorded. Data are from the same penetration during which the unit in B was recorded. The position of the green symbol indicates that this unit was positioned in the deep layers. See also Figure 1—figure supplements 1–3. (G). Similar to F, for the penetration during which the unit shown in D was recorded. (H) Receptive field contours for multiunit activity recorded on different electrode contacts from the penetration shown in F. Contours are drawn at z = 3. Orthogonality of the penetration was evaluated by fitting a line through the centers of the receptive field contours and computing D, the distance between pairs of azimuth and elevation coordinates of receptive field centers per mm depth (Methods). (I) Similar to H, for the penetration shown in G.

Figure 1—figure supplement 1. Construction of current source density (CSD) map.

Data shown from an example penetration. (A) Average local field potential (LFP) from each electrode contact in response to small rings positioned in the classical receptive field (cRF). (B) CSD is computed as the second spatial derivative of the LFP. Left panel: CSD traces. Negative values correspond to current sinks, positive values to current sources. Middle panel: CSD traces plotted on a color scale. Right panel: smoothed CSD map (Methods). Symbols and lines between compartments drawn as in Figure 1F and G. Black solid triangle indicates position of most superficial electrode contact on which multiunit activity was recorded. (C) cRF contours for different electrodes from this penetration (contours drawn at z = 3). (D) is an estimate of the orthogonality as the distance between the receptive field centers per mm depth (as in Figure 1H and I; Methods).

Figure 1—figure supplement 2. Additional examples of current source density (CSD) maps.

Each panel shows a CSD map from a different penetration. Distance from center of granular layer is shown along ordinate on the left, and the number of electrode contact on the right (higher numbers correspond to more superficial contacts). Reddish colors are current sinks, blueish colors are current sources. Symbols as in Figure 1F and G. Black solid triangles indicate position of most superficial electrode contact on which multiunit activity was recorded (in cases where this could be determined, that is for which the most superficial contact did not record multiunit activity). Sink–source patterns are strikingly similar to those reported in the behaving macaque in V4 by other laboratories (Pettine et al., 2019, their Figure 1C Lu et al., 2018, their Figure S4B), and in another downstream cortical area (area 36: Takeuchi et al., 2011, their Figure S1). Top row panels are from penetrations from animal D, bottom panels are from penetrations from animal Z.

Figure 1—figure supplement 3. Consistency of current source density (CSD) maps between studies and cortical areas.

(A) Population average of CSD maps. Individual CSD maps were aligned relative to the border between granular layer and deep layers. The average of these aligned maps was computed for the 81 penetrations that were used in the laminar analyses (interpretable CSD maps). Black solid triangle indicates the average position of most superficial electrode contact on which multiunit activity was recorded for these penetrations. (B) Two examples of CSD maps from another study in V4 in the awake macaque (Pettine et al., 2019, their Figure 1C). Reddish colors are current sinks, blueish colors are current sources. Current sink/source pattern (symbols) is consistent with the population average in our study (panel A) as well as with individual penetrations (Figure 1; Figure 1—figure supplements 1 and 2). Dotted line drawn by Pettine et al., 2019 below the prominent current sink with short latency (star). Modified from Laminar segregation of sensory coding and behavioral readout in macaque V4. Pettine WW, Steinmetz NA, Moore T. Proc Natl Acad Sci U S A. 2019 Jul 16;116(29):14749–14754. doi:10.1073/pnas.1819398116. Reprinted with permission from PNAS. Further reproduction of this panel would need permission from the copyright holder. (C) Population average of CSD from a study in medial temporal cortex in the awake macaque (Takeuchi et al., 2011, their Figure S1A). Current sink–source pattern (symbols) is consistent with the population average in our study (panel A). Takeuchi et al., 2011 applied electrolytic lesion marks on electrode contacts in six penetrations, and were able to verify histologically that the earliest current sink (indicated by white star) corresponds to the granular layer. Reprinted from Reversal of interlaminar signal between sensory and memory processing in monkey temporal cortex. Takeuchi D, Hirabayashi T, Tamura K, Miyashita Y. Science. 2011 Mar 18;331(6023):1443–1447. doi:10.1126/science.1199967. Reprinted with permission from AAAS. This panel is not covered by the CC-BY 4.0 licence and further reproduction of it would need permission from the copyright holder.

© 2019, National Academy of Sciences permissions

Modified from Laminar segregation of sensory coding and behavioral readout in macaque V4. Pettine WW, Steinmetz NA, Moore T. Proc Natl Acad Sci U S A. This panel is not covered by the CC-BY 4.0 licence and further reproduction of it would need permission from the copyright holder.

© 2011, American Association for the Advancement of Science permissions

Reprinted with permission from AAAS: Takeuchi D, Hirabayashi T, Tamura K, Miyashita Y. Science. 2011 Mar 18;331(6023):1443-7. This panel is not covered by the CC-BY 4.0 licence and further reproduction of it would need permission from the copyright holder.