[Eeglablist] [EXTERNAL] 16 Hz artifact with lower harmonics in data

[Brian Harvey]

The FFT has an unusual 1/f characteristic. Question(s)


  1.  Awake or anesthetized (if so what anesthesia)
  2.  Did you perform any filtering, referencing, or resampling?
  3.  Have you looked at the raw data, plot the raw traces outside of EEGlab

Brian

From: eeglablist <eeglablist-bounces at sccn.ucsd.edu> On Behalf Of Malte Anders
Sent: Thursday, March 31, 2022 6:21 AM
To: EEGLAB List <eeglablist at sccn.ucsd.edu>
Subject: [EXTERNAL] [Eeglablist] 16 Hz artifact with lower harmonics in data

Dear all, We are currently trying to record EEGs on the open brain of certain animals - so no "standard" human recordings. The gold electrodes are placed directly on the brain, without any conductive gel applied. We are encountering a strange ZjQcmQRYFpfptBannerStart
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Dear all,



We are currently trying to record EEGs on the open brain of certain animals

- so no "standard" human recordings. The gold electrodes are placed

directly on the brain, without any conductive gel applied.



We are encountering a strange ~16 Hz artifact, with harmonics around ~10.x

Hz and ~5.x Hz, see these images:

https://urldefense.proofpoint.com/v2/url?u=https-3A__ibb.co_NKMcrf0&d=DwIBaQ&c=-35OiAkTchMrZOngvJPOeA&r=kB5f6DjXkuOQpM1bq5OFA9kKiQyNm1p6x6e36h3EglE&m=c88_VOjmnuVwvN-A41WN_LrcUXdxqhHwgozv6g_vBGXNTPB1AS0LrJkqDp8M8B44&s=E8I2mkOB0AmaOPUEUXwPZvKu-BkYWuzhow82gl11YCg&e=

https://urldefense.proofpoint.com/v2/url?u=https-3A__ibb.co_Z8zkCpp&d=DwIBaQ&c=-35OiAkTchMrZOngvJPOeA&r=kB5f6DjXkuOQpM1bq5OFA9kKiQyNm1p6x6e36h3EglE&m=c88_VOjmnuVwvN-A41WN_LrcUXdxqhHwgozv6g_vBGXNTPB1AS0LrJkqDp8M8B44&s=haiZvyK3aT-jVpA4wpHVfjQQrPRs1O0cx88EnN9NitE&e=



Anybody ever saw artifacts in these frequency ranges? I am trying to narrow

down if those artifacts stem from our recording setup itself (maybe bad

impedance between the brain and the measuring electrode?), or from any

other external hardware in our recording setup.



Any help is much appreciated!

Malte

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