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bionicvisionlab.org
Bionic Vision Lab
@bionicvisionlab.org
470 followers 170 following 130 posts
👁️🧠🖥️🧪🤖 What would the world look like with a bionic eye? Interdisciplinary research group at UC Santa Barbara. PI: @mbeyeler.bsky.social‬
#BionicVision #Blindness #NeuroTech #VisionScience #CompNeuro #NeuroAI
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bionicvisionlab.org
Our final poster at #SfN2025 explores human-in-the-loop optimization for intracortical microstimulation, presented by @lozaneuro.bsky.social, in collaboration with @umh.es:

PSTR450.20
Nov 19 at 1:00 PM
www.abstractsonline.com/pp8/#!/21171...

#SfN25 #VisionScience #NeuroTechnology
Schematic labeled human-in-the-loop optimization (HILO). It shows two stimuli on the left: pulse trains with varying stimulus amplitude over time. A participant has to choose which stimulus appears brighter. This feedback is used to inform a Gaussian process model that chooses the next stimulus pair, with the goal of finding the stimulus with the lowest overall charge to elicit perception
November 16, 2025 at 6:58 PM
bionicvisionlab.org
Lily Turkstra is presenting new findings on stimulus-selective spiking activity recorded during a working memory experiment in a unique intracortical dataset.

PSTR341.13
Nov 18 at 1:00 PM
www.abstractsonline.com/pp8/#!/21171...

#SfN25 #VisionScience #Neuroscience
left: experimental setup showing an implantee with an introcortical prosthesis and example phosphenes described as a large filled circle, a half-moon, and a tiny dot. right: schematic showing cross-temporal decoding of delay period activity. Over 406 trials, working memory content could be decoded during the delay period in 88.5% of delay period windows.
November 16, 2025 at 6:58 PM
bionicvisionlab.org
Our second poster at #SfN2025 dives into biologically plausible networks for efficient image encoding, presented by Hasith Basnayake:

PSTR154.08
Nov 17 at 8:00 AM
www.abstractsonline.com/pp8/#!/21171...

#SfN25 #VisionScience #NeuroTechnology
Table showing different network diagrams under test, trained either on MNIST or Fashion-MNIST, with either soft or hard winner-take-all (WTA) wiring. Synaptic weights showed either holistic or parts-based representations of images
November 16, 2025 at 6:58 PM
bionicvisionlab.org
🧠 Building on Roksana Sadeghi’s work: Calibrating retinal implants is slow and tedious. Can Gaussian Process Regression (GPR) guide smarter sampling?

✅ GPR + spatial sampling = fewer trials, same accuracy
🔁 Toward faster, personalized calibration

🔗 bionicvisionlab.org/publications...

#EMBC2025
Efficient spatial estimation of perceptual thresholds for retinal implants via Gaussian process regression | Bionic Vision Lab
We propose a Gaussian Process Regression (GPR) framework to predict perceptual thresholds at unsampled locations while leveraging uncertainty estimates to guide adaptive sampling.
bionicvisionlab.org
July 13, 2025 at 5:24 PM
bionicvisionlab.org
🎓 Proud of our undergrad(!) Eirini Schoinas for leading this:
bionicvisionlab.org/publications...

🧠 Human-in-the-loop optimization (HILO) works in silico—but does it hold up with real people?
✅ HILO outperformed naïve and deep encoders
🔁 A step toward personalized #BionicVision

#EMBC2025
Evaluating deep human-in-the-loop optimization for retinal implants using sighted participants | Bionic Vision Lab
We evaluate HILO using sighted participants viewing simulated prosthetic vision to assess its ability to optimize stimulation strategies under realistic conditions.
bionicvisionlab.org
July 13, 2025 at 5:24 PM
bionicvisionlab.org
This matters. Checkerboard rastering:

✔️ works across tasks
✔️ requires no fancy calibration
✔️ is hardware-agnostic

A low-cost, high-impact tweak that could make future visual prostheses more usable and more intuitive.

#BionicVision #BCI #NeuroTech
July 9, 2025 at 4:55 PM
bionicvisionlab.org
✅ Checkerboard consistently outperformed the other patterns—higher accuracy, lower difficulty, fewer motion artifacts.

💡 Why? More spatial separation between activations = less perceptual interference.

It even matched performance of the ideal “no raster” condition, without breaking safety rules.
Boxplots showing task accuracy for two experimental tasks—Letter Recognition and Motion Discrimination—grouped by five raster patterns: No Raster (blue), Checkerboard (orange), Vertical (green), Horizontal (brown), and Random (pink). Each colored boxplot shows the median, interquartile range, and individual participant data points. In both tasks, Checkerboard and No Raster yield the highest median accuracy. Horizontal and Random patterns perform the worst, with more variability and lower scores. Significant pairwise differences (p < .05) are indicated by horizontal bars above the plots, showing that Checkerboard significantly outperforms Random and Horizontal in both tasks. A dashed line at 0.125 marks chance-level performance (1 out of 8). These results suggest Checkerboard rastering improves perceptual performance compared to conventional or unstructured patterns.
July 9, 2025 at 4:55 PM
bionicvisionlab.org
We ran a simulated prosthetic vision study in immersive VR using gaze-contingent, psychophysically grounded models of epiretinal implants.

🧪 Powered by BionicVisionXR.
📐 Modeled 100-electrode Argus-like array.
👀 Realistic phosphene appearance, eye/head tracking.
Diagram showing the four-step pipeline for simulating prosthetic vision in VR. Step 1: A virtual camera captures the user’s view, guided by eye gaze. The image is converted to grayscale and blurred for preprocessing. Step 2: The preprocessed image is mapped onto a simulated retinal implant with 100 electrodes. Electrodes are activated based on local image intensity and grouped into raster groups. Raster Group 1 is highlighted. Step 3: Simulated perception is shown with and without rastering. Without rastering (top), all electrodes are active, producing a more complete but unrealistic percept. With rastering (bottom), only 20 electrodes are active per frame, resulting in a temporally fragmented percept. Phosphene shape depends on parameters for spatial spread (ρ) and elongation (λ). Step 4: The rendered percept is updated with temporal effects and presented through a virtual reality headset.
July 9, 2025 at 4:55 PM
bionicvisionlab.org
Checkerboard rastering has been used in #BCI and #NeuroTech applications, often based on intuition.

But is it actually better, or just tradition?

No one had rigorously tested how these patterns impact perception in visual prostheses.

So we did.
Raster pattern configurations used in the study, shown as 10×10 electrode grids labeled with numbers 1 through 5, representing five sequentially activated timing groups. 1. Horizontal: Each row of electrodes belongs to one group, with activation proceeding top to bottom. 2. Vertical: Each column is a group, activated left to right. 3. Checkerboard: Electrode groups are arranged to maximize spatial separation, forming a checkerboard-like layout. 4. Random: Group assignments are randomly distributed across the grid, with no spatial structure. This pattern was re-randomized every five frames to test unstructured activation. Each group is represented with different shades of gray and labeled numerically to indicate activation order.
July 9, 2025 at 4:55 PM
Reposted by Bionic Vision Lab
mbeyeler.bsky.social
Last but not least is Lily Turkstra, whose poster is assessing the efficacy of visual augmentations for high-stress navigation:

Tue, 2:45 - 6:45pm, Pavilion: Poster #56.472
www.visionsciences.org/presentation...

👁️🧪 #XR #VirtualReality #Unity3D #VSS2025
VSS PresentationPresentation – Vision Sciences Society
www.visionsciences.org
May 20, 2025 at 2:10 PM
Reposted by Bionic Vision Lab
mbeyeler.bsky.social
Coming up: Jacob Granley on whether V1 maintains working memory via spiking activity. Prior evidence from fMRI and LFPs - now, rare intracortical recordings in a blind human offer a chance to test it directly. 👁️ #VSS2025

🕥 Sun 10:45pm · Talk Room 1
🧠 www.visionsciences.org/presentation...
Schematic illustrating the phosphenes elicited by an intracortical prosthesis. A 96-channel Utah array is shown, stimulated with biphasic pulse trains. An arrow points to drawings of visual percepts elicited by electrical stimulation Jacob Granley headshot
May 18, 2025 at 12:26 PM