Material damage to multielectrode arrays after electrolytic lesioning is insignificant
- Electrical Engineering Department, Stanford University, United States
- Bioengineering Department, Stanford University, United States
- Neurosurgery Department, Stanford University, United States
- Wu Tsai Neurosciences Institute, Stanford University, United States
Figures
Figure 1 with 1 supplement
Heatmaps of damage scores (0–3) across the five identified types of damage and across the four imaged lesioning arrays.
Electrodes are displayed using the orientation in Video 1 (electrode tips facing viewer, wire bundle on the right). Second-to-rightmost column displays summed damage scores for each array across the five types of damage. Electrodes used for electrolytic lesioning are denoted with blue dots. Median summed scores for each radial section of the array are plotted in the bar charts to the right of the heatmaps. Ring layout and numbering information are available in Video 1—source data 2. Unwired electrodes (electrodes not wire bonded at time of manufacture) and electrodes with shank fractures are ignored and displayed in black, as they are not scored.
Figure 1—figure supplement 1
Heatmaps of damage scores (0–3) across the five identified types of damage and across all eight intact, imaged non-human primate (NHP) arrays.
Electrodes are displayed using the orientation in Video 1 (electrode tips facing viewer, wire bundle on the right). Second-to-rightmost column displays summed damage scores for each array across the five types of damage. Electrodes used for electrolytic lesioning are denoted with blue dots. Median summed scores for each radial section of the array are plotted in the bar charts to the right of the heatmaps. Ring layout and numbering information is available in Video 1—source data 2. Unwired electrodes (electrodes not wire bonded at time of manufacture) and electrodes with shank fractures are ignored and displayed in black, as they are not scored.
Figure 2 with 1 supplement
Stacked histograms of damage scores (0–3) across the five identified types of damage and across the four imaged lesioning arrays.
Gray indicates normal electrodes, and black indicates lesioning electrodes. The rightmost column displays the average distribution of damage scores across the five types of damage. Electrodes with shank fractures (SF) are ignored, as they are not scored.
Figure 2—figure supplement 1
Stacked histograms of damage scores (0–3) across the five identified types of damage and across all eight intact, non-human primate (NHP) imaged arrays.
Gray indicates normal electrodes, and black indicates lesioning electrodes. Rightmost column displays the average distribution of damage scores across the five types of damage. Electrodes with shank fractures (SF) are ignored, as they are not scored.
Figure 3 with 4 supplements
Correlation plot (Pearson’s R) across the five different damage types.
AD = abnormal debris, TB = tip breakages, CC = metal coating cracks, PC = parylene C cracks, PD = parylene C delamination. Results demonstrate overall low correlation (magnitude < 0.25) across different damage types, with the exception of coating cracks and tip breakage, with a correlation coefficient of 0.47. Test values with Bonferroni-corrected p < 0.05 are displayed with asterisks. Raw p-values are separately available in Supplementary file 2. Electrodes with shank fractures are ignored, as they are not scored.
Figure 3—figure supplement 1
Correlation plots (Pearson’s R) for each of the five rings across all four imaged lesioning arrays.
(Row 1, right to left: R1 and R2; row 2: R3 and R4; bottom row: R5). Test values with Bonferroni-corrected p < 0.05 are displayed with asterisks. Raw and p-values are separately available in Supplementary file 5.
Figure 3—figure supplement 2
Scatterplots of the lesion electrodes’ damage scores over the target current for each lesion.
A best-fit line is also plotted along with regression results. In cases where only one target current was used (ie. subjects with only one lesion), linear regression was not performed. No best-fit lines were statistically significant at p = 0.05.
Figure 3—figure supplement 3
Scatterplots of the lesion electrodes’ damage scores over the target lesioning procedure duration for each lesion.
A best-fit line is also plotted along with regression results. In cases where only one duration was used (ie. subjects with only one lesion, subjects with the same duration across all lesions), linear regression was not performed. Scatterplots with statistically significant lines of best fit are starred in yellow.
Figure 3—figure supplement 4
Histograms of the lesion electrodes’ damage scores, separated by array material.
Blue bars are IrOx arrays and orange bars are Pt arrays. The first row shows scores across all eight scored non-human primate (NHP) arrays (n = 384 IrOx electrodes, n = 384 Pt electrodes). The second row shows scores for only the four NHP arrays used for lesioning (n = 192 IrOx electrodes, n = 192 Pt electrodes). The third row shows scores for only the subset of electrodes used for NHP lesioning (n = 10 IrOx electrodes, n = 20 Pt electrodes). Notably, it appears that platinum arrays imaged in this work generally appear to report less damage than iridium oxide arrays when considering all arrays. Additionally, the imaged platinum arrays appear to always report less parylene C damage. However, platinum arrays generally appear to report more other types of damage (abnormal debris, tip breakage, coating cracks) when used for lesioning. This supports previous literature that indicates IrOx may be more resistant to stimulation-related damage than Pt (Cogan et al., 2004; Negi et al., 2010; Chen et al., 2023; Bjånes et al., 2024). It is important to note that many other factors, such as time in tissue, explant surgery, and immune response of the specific implant subject, all impact the conclusions of this analysis.
Videos
Video 1
Interactive display: Video demonstrates how to use the interactive display of all captured scanning electron microscopy (SEM) array images, available through the provided link.
Once an array has been selected, a diagram of each array’s anatomical position (derived from surgical drawings and notes) appears, along with an SEM image of the array. All array images are displayed with the wire bundle to the right side and with electrode tips facing the viewer. Specific electrodes may be selected from the array image; SEM images of each electrode and their scores in each of the five damage categories will appear along with any additional notes. Furthermore, examples of specific scores for each damage type are selectable through an additional drop-down menu for each array. Similarly, electrodes used for electrolytic lesioning are also selectable through an additional drop-down menu for each array.
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Video 1—source data 1
Tutorial video for interactive display.
- https://cdn.elifesciences.org/articles/106452/elife-106452-video1-data1-v1.zip
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Video 1—source data 2
Numbering layout of the electrodes as imaged (pins facing outwards, towards the reader).
Wire bundle is arranged to the right. Each radial section of the array is also color-coded and labeled. R1 refers to the innermost core electrodes of the array, R2 refers to the next outer ring of the array, and so on.
- https://cdn.elifesciences.org/articles/106452/elife-106452-video1-data2-v1.pdf
Additional files
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MDAR checklist
- https://cdn.elifesciences.org/articles/106452/elife-106452-mdarchecklist1-v1.pdf
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Supplementary file 1
Details and characteristics for all imaged and analyzed devices in this work.
- https://cdn.elifesciences.org/articles/106452/elife-106452-supp1-v1.pdf
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Supplementary file 2
Shapiro-Wilk p-values.
- https://cdn.elifesciences.org/articles/106452/elife-106452-supp2-v1.csv
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Supplementary file 3
Mann-Whitney U and Levene p-values when comparing damage scores given to lesioning/non-lesioning electrodes.
- https://cdn.elifesciences.org/articles/106452/elife-106452-supp3-v1.csv
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Supplementary file 4
Mann-Whitney U and Levene p-values when comparing total damage scores given to arrays used for lesioning/non-lesioning.
- https://cdn.elifesciences.org/articles/106452/elife-106452-supp4-v1.csv
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Supplementary file 5
Correlation r and p-values.
- https://cdn.elifesciences.org/articles/106452/elife-106452-supp5-v1.pdf
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Supplementary file 6
Details for electrolytic lesions referenced in this manuscript.
- https://cdn.elifesciences.org/articles/106452/elife-106452-supp6-v1.csv
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Material damage to multielectrode arrays after electrolytic lesioning is insignificant
eLife 14:RP106452.
https://doi.org/10.7554/eLife.106452.3
