Advanced multiplexing: Multi-level illumination and extended frequency encoding for high-density fNIRS

Alexander von Lühmann, David Boas, Meryem Yücel, Yuanyuan Gao

Duration: 90 min

Capacity: 30

Level: Introductory

Demo Tech.

Requirements: none

Synopsis: Excellent signal quality and a good sampling rate are basic requirements for fNIRS research. A suite of strategies can be applied to maintain high performance in demanding applications with a large channel count or multi-distance measurements (high density). The course will introduce attendees to basic multiplexing concepts, trade-offs, and approaches to achieve a high dynamic range, signal quality, and sampling rate in applications with high channel density. The knowledge will then be applied in a demo showing new features of the NIRx NIRSport2 with Aurora and NIRSite software.

1. Motivation

2. Introduction to temporal, spatial, and frequency multiplexing in fNIRS

3. Implications for high-density fNIRS measurements

4. New features: Extended frequency encoding and multi-timestep and -level illumination

5. Demo: how to use the new features in NIRSite and Aurora

Learning objectives: After the course, you will have learned:

  • the theoretical considerations behind temporal, spatial, and frequency multiplexing in fNIRS
  • the practical implications of multi-level illumination and frequency encoding for high-density fNIRS
  • how both are applied in fNIRS measurements with NIRx’ NIRSite and Aurora software

Software download (Optional): To download the Aurora and NIRSite software at, you will need to request access to NIRx’ support center under