Project: Anschutz (112 OPM sensors) minus bad channels
Subject ID: AS24
Date: December 14, 2021
Paradigm: Auditory Monaural Left Ear (no sound in RE)

NOTE: there is a 34 ms delay between the trigger and the tone delivered to the earpiece. Thus for example, if the N100 is at 100 ms, it will appear at 134 ms.
Stimulus software: E-pPrime

AUDITORY Paradigm / Tonotopy
Template: TONOTOPY
frequencies: 250, 1000, 4000 Hz in separate files
Tested hearing threshold at each frequency to compensate for both human hearing differences and (more importantly) variable frequency response of the delivery system 

The duration of the tones was 100 ms with a 5 ms rise and fall time.
Left ear
ISI: 2 sec (random 500 ms component, so it can be a low as 1.75 sec or as high as 2.25 seconds)
5 minutes per frequency

Hearing threshold 1000 Hz: 38 dB
Hearing threshold 250 Hz: 38 dB
Hearing threshold 4000 Hz: 48 dB
Sound levels: 250 Hz 102 db SPL, for 1 kHz 92 db SPL, and for 4 kHz 83 db SPL

Triggers

250 Hz data, Stimulus Chan = Input3, value = 3 
1000 Hz data, Stimulus Chan = Input4, value = 3
4000 Hz data, Stimulus Chan = Input 5, value =3 

Coregistration
Coregistration is based on Two Polhemus measurements. 5 points on the helmet is co-registered to the participant’s head coordinate frame, which is sufficient to define a rotation and translation matrix between head frame and device frame

Sensor layout:
¬
Sample plots
4 tsp projectors were added, 0.5 to 30 Hz, and notches at 60 and 3 harmonics.

250 Hz data
¬¬
 1000 Hz data
¬¬
 4000 Hz data

¬¬