Fig 1.
LOC localizer and location of arrays.
Top: site of Utah array implantation (black) projected onto 3D rendering of the brain in patient 1 (left) and patient 2 (right), overlayed with the fMRI LOC localizer activation (contrast [shapes + outlines] − [scrambled shapes + scrambled outlines]; p < 0.05, FWE-corrected for multiple comparisons). Center: LOC localizer stimuli (shapes, scrambled shapes, outlines, scrambled outlines), see [17]. Bottom: axial, coronal, and sagittal view. T-values plotted on T1-weighted image. Crosshair indicates the position of the Utah array in relation to the fMRI activation for both patients. The underlying data can be found at doi:10.5061/dryad.qd4vd71. 3D, three-dimensional; fMRI, functional magnetic resonance imaging; FWE, family-wise error; LOC, lateral occipital complex.
Table 1.
Position of the micro-electrode array in relation to the centroid of fMRI activations in the literature [18,19]. Coordinates are shown in MNI space for the LH and RH.
Fig 2.
Single- and multi-unit normalized net response.
Net spike rate divided by the average spike rate for the best condition (50–300 ms after stimulus onset) to images of objects and scrambled controls. (A) Example neuron. Average response to intact (red) and scrambled (blue) shapes (left) and line stimuli (right). The inset illustrates the spike waveform. (B) Average single-unit responses across all visually responsive channels in patient 1. (C, D) Average multi-unit responses to intact and scrambled stimuli in patient 1 and 2, respectively, across all visually responsive channels. The underlying data can be found at doi:10.5061/dryad.qd4vd71. Pt1, patient 1; Pt2, patient 2; scr, scrambled.
Fig 3.
Time-frequency plots of the average LFPs.
Indicating that the high-gamma (80–120 Hz) power is significantly stronger for intact shapes and outlines than for their scrambled controls. The underlying data can be found at doi:10.5061/dryad.qd4vd71. LFP, local field potential; scr, scrambled.
Fig 4.
(A, C) This neuron responded more to intact shapes and lines than to their scrambled versions as shown in these spike raster plots. (B, D) Response to the 5 best and 5 worst stimuli, indicating that this neuron discriminated reliably between different shapes. scr, scrambled.
Fig 5.
Ranking analyses of shapes and lines for SUA in patient 1. The same ranking is applied for the corresponding scrambled control stimuli. The underlying data can be found at doi:10.5061/dryad.qd4vd71. SUA, single-unit activity.
Fig 6.
Ranking of shapes for MUA and high-gamma LFP for each patient. The same ranking is applied for the neighboring channels and the corresponding scrambled control stimuli. An overview of the array is shown as inset; each square represents an electrode, illustrating that electrodes with high d′ values (response nonscrambled versus scrambled) are neighbored by electrodes with low d′ values. The underlying data can be found at doi:10.5061/dryad.qd4vd71. LFP, local field potential; MUA, multi-unit activity.
Table 2.
Slope of regression lines with 95% confidence interval for shapes and lines.
The same ranking was applied for the scrambled versions of the stimuli and for their neighboring channels, respectively.
Fig 7.
(A) Single-unit data. The first 4 panels show the RFs of 4 example neurons. All responses are normalized to the maximum visual response. Black dots indicate responses higher than 50% of the maximum response (per channel). Rightmost panel: average RF for all visually responsive channels. (B) Average RF for high-gamma responses for patient 1 (left) and patient 2 (right). The underlying data can be found at doi:10.5061/dryad.qd4vd71. RF, receptive field; SUA, single-unit activity.
Fig 8.
(A) Stimuli. (B) T-values for main effects of stereo, contrast [curved stereo + flat stereo]–[curved control + flat control], plotted on T1-weighted image. p < 0.05, FWE-corrected for multiple comparisons. Crosshair indicates the position of the Utah array. The overlap of the LOC localizer and stereo fMRI is shown in S4 Fig. (C) Example single neuron (left column), average single-unit responses (middle column), and average multi-unit responses (right column) to preferred (red) and nonpreferred (blue) curved surfaces at 3 positions in depth (upper row: near; middle row: center; and bottom row: far). (D) Time-frequency power spectra of an example channel in patient 2 for convex and concave stimulus presentations at 3 positions in depth. This site is selective for convex shapes across different positions in depth. The underlying data can be found at doi:10.5061/dryad.qd4vd71. fMRI, functional magnetic resonance imaging; FWE, family-wise error; LFP, local field potential; LOC, lateral occipital complex; MUA, multi-unit activity; nonpref, nonpreferred stimulus; Pt1, patient 1; Pt2, patient 2; pref, preferred stimulus; SUA, single-unit activity.
Fig 9.
Clustering of the 3D-structure preference.
d′ values (convex versus concave) of high-gamma responses across both arrays. High-gamma 3D-structure preference was highly localized on individual electrodes, since recording sites with a high d′ (convex versus concave) were frequently located next to recording sites with a low d′. The underlying data can be found at doi:10.5061/dryad.qd4vd71. 3D, three-dimensional; Pt1, patient 1; Pt2, patient 2.