Project: Anschutz (112 OPM sensors)
Subject: JH
Subject ID: AS27
Date: December 16, 2021
Paradigm: Visual Gamma

Visual Gamma Paradigm
Use Presentation software and file from Lauri
Template: not sure
Concentric rings start shrinking
Fixation cross in the center
Speed of contraction changes at random point in time (2.5 sec/ trial)
If speed changes, subject has to press the button
Trigger signal comes from parallel port of the presentation computer
10 min recordings

Triggers
Channel 00:00        HPI
Channel 01:00        response button
Channel 03:00        BNC 1 (bit 2)
Channel 04:00        BNC 2 (bit 4)
Channel 05:00        Sensor localization (Tyler’s box)
Channel 06:00        BNC 3 (bit 8)

Sensor positions
If a location is 00 for x, y, and z, it is a bad channel

Coregistration
Before and after measurement day
HPI coils 1-5, one measurement per file 
43 Hz sine wave
100  Ohm resistor
10 sec measured at two amplitudes: 0.05 V and 0.5V

Two Polhemus files:
Polhemus head shape measurement outside the helmet and inside the helmet
Five point Polhemus file has fiducially, HPI coils, and 5 points on the OPM helmet
	LPA, RPA, Nasion are the fiducials
	Cz, Inion are the coil positions taped to the eyebrow/temple region
	Coil1=LPA coil
	Coil2=RPA coil
	Coil3=Nasion coil
	Coil4=Cz coil around left eyebrow
	Coil5=Inion around right eyebrow
	OPM1-5 are the following reference points on the helmet
	OPM1=Point 1
	OPM2=Point 4
	OPM3=Point 2
	OPM4=Point 3
	OPM5=Point 5
The coordinates in the sensor frame are:

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