American Society of Hirudotherapy

An optically stabilized fast-switching light emitting diode as a light source for functional neuroimaging

Methodology study published in PLoS ONE (2012)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: In vitro / laboratorySalivary PharmacologyWagenaar DA · PloS one, 2012

Abstract

Neuroscience research increasingly relies on optical methods for evoking neuronal activity as well as for measuring it, making bright and stable light sources critical building blocks of modern experimental setups. This paper presents a method to control the brightness of a high-power light emitting diode (LED) light source to an unprecedented level of stability. By continuously monitoring the actual light output of the LED with a photodiode and feeding the result back to the LED's driver by way of a proportional-integral controller, drift was reduced to as little as 0.007% per hour over a 12-h period, and short-term fluctuations to 0.005% root-mean-square over 10 seconds. The LED can be switched on and off completely within 100 μs, a feature that is crucial when visual stimuli and light for optical recording need to be interleaved to obtain artifact-free recordings. The utility of the system is demonstrated by recording visual responses in the central nervous system of the medicinal leech Hirudo verbana using voltage-sensitive dyes.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal ArticleResearch Support, Non-U.S. Gov't
Indexed MeSH termsAnimalsCells, CulturedDiagnostic Techniques, NeurologicalFunctional NeuroimagingLeechesLightLightingModels, BiologicalOptics and PhotonicsVision, OcularVisual Pathways

Summary

Stable LED light source for functional neuroimaging demonstrated by recording visual responses in medicinal leech Hirudo verbana CNS — methodology valuable for leech neurobiology research.

Why This Matters for Hirudotherapy

This paper presents an engineering method for stabilizing high-power LED brightness using photodiode feedback and proportional-integral control, achieving drift of 0.007% per hour over 12 hours and 100-microsecond switching, and demonstrates the system by recording visual responses in the central nervous system of the medicinal leech Hirudo verbana using voltage-sensitive dyes. For ASH's domain, the medicinal leech serves only as a model organism for demonstrating the optical system's capability in neuroscience experiments; the study is fundamentally about light source engineering, not hirudotherapy or leech biology. There is no defensible relevance to therapeutic leech application, the leech secretome, or ASH's domain.

Citation

An optically stabilized fast-switching light emitting diode as a light source for functional neuroimaging.

Wagenaar DA · PloS one, 2012

DOI

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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