Temporal resolution of CW fNIRS devices

1 min read

This is a guest post by Ning Liu from Stanford University.

Temporal resolution provides information on the distance of time between the acquisitions of two images (data) of the same area. It is the reciprocal of sampling rate (or acquisition rate) of an fNIRS device. For some devices, sampling rate is a fixed number; for some other ones, sampling rate may depend on number of sources or detectors to use. Why is that? It is because they have different instrumental design. For those with unfixed sampling rate, multiple sources time-share an optical detector by means of a multiplexing circuit that turns the sources on and off in sequence, so that only one source within the detector range is on at any given time. The NIRx system, for instance, are using this type of design. For those with fixed sampling rate, they usually use low frequency modulated light source to provide the excitation light, thus one detector can ‘see’ only one source.

For instance, Hitachi ETG4000 system has sampling rate of 10Hz (from http://www.hitachi.com/businesses/healthcare/products-support/opt/etg4000/contents2.html), thus its temporal resolution is 100ms. Some other device, such as NIRScout, has sampling rate from 2.5 – 62.5 Hz (from https://nirx.net/nirscout/), thus its temporal resolution is 16 – 400ms. Why the sampling rate is changing from 2.5 – 62.5 Hz? That’s because users can choose different number of sources and detectors in their configuration. The more number of sources and detectors to use, the smaller the sampling rate. The following table is from a review article (Scholkmann, et al., 2014) on NeuroImaging volume 85 (2104), a special issue of functional near-infrared spectroscopy. It summarizes the specifications of some popular commercially available fNIRS devices, mainly focused on continuous wave devices.

Time resolution of NIRS devices
Time resolution of NIRS devices (click to enlarge, F. Scholkmann et al. / NeuroImage 85 (2014) 6–27)

本文作者为斯坦福大学刘宁。她提供NIRS培训服务。



写作助手,把中式英语变成专业英文


Want to receive new post notification? 有新文章通知我

第六十期fNIRS Journal Club通知2025/3/8, 10am 邹立业教授团队

长时间久坐行为往往会引起脑血流供应不足,进而导致注意力下降及执行功能表现减弱,并影响人脑学习的信息加工过程。以往研究表明体育活动对执行功能表现具有积极作用。然而,关于在久坐期间进行短时有氧运动干预是否
Wanling Zhu
14 sec read

第五十九期fNIRS Journal Club视频 赵斐博士

Youtube: https://youtu.be/dIlSEsJvHm8 优酷:https://v.youku.com/v_show/id_XNjQ1MDE3OTY2MA==.html?spm=a2
Wanling Zhu
17 sec read

第五十九期fNIRS Journal Club通知2025/1/11, 10am 赵斐博士

糖尿病患者持续的高血糖水平会导致全身蛋白质的结构和功能变化,以及大脑中蛋白质聚集体的积累,影响认知功能。来自美国Wayne State University的赵斐博士将分享一项使用功能性近红外光谱(f
Wanling Zhu
12 sec read

One Reply to “Temporal resolution of CW fNIRS devices”

  1. Hello Ning and Xu,

    Great read, thanks for this!

    Just wanted to let you know that the NIRScout has been extended to 100hz max sampling rate with the newest version of NIRStar 15-2, so the typical range for sampling with that system would then be roughly ~4-100hz, depending on the source illumination multiplexing sequence.

    Keep up the great work!

    Sincerely,

    Thomas Johannsen
    NIRx Medical Technologies

Leave a Reply

Your email address will not be published. Required fields are marked *