Goals

  The experiment aims to record and analyze the EEG of Parkinson
  patients who have received Deep Brain Stimulation (DBS) implants,
  while presented with certain moving or stationary visual stimuli,
  with the DBS on and off.
  
  The visual stimuli and the experimental protocol are designed to
  drive the patient into executing certain visual analysis and
  recognition tasks and/or to elicit involuntary "pseudo-motor"
  responses in his cortex.
  
  The analysis aims to detect and model possible changes in the
  patient's brain activity related to those tasks and elicited
  responses that are correlated with the DBS on/off status.
  
Equipment and parameters

  During the active part of the experiment, the subject sits on a
  padded chair with torso upright??, head upright and unsupported,
  with both arms on chair armrests.

  The EEG signals are collected by 19 electrodes glued directly to the
  scalp, without a support net or cap. The signals are digitized and
  recorded by a Model ??? EEG unit made by ???. The potential
  reference is provided by ???. The sampling frequency is 500 Hz, the
  maximum allowed by the recorder.
  
  A flat computer monitor screen, ?? cm x ?? cm, is placed ?? cm away,
  with the center on the same level as the patient's eyes. The screen
  is controlled by a laptop (Model ?? by ???) via an HDMI? cable.
  
  A simple photodiode circuit, the screen brightness sensor (SBS), is
  affixed onto a corner of the display screen and monitors the
  brigtness of a rectangular color patch displayed at that position by
  the stimulus presentation software. Its output, that varies between
  0.00 and -0.25 V, is recoded in a separate file, synchronized with the
  EEG recording.
  
  For most of the time, the experimenters and the computer are located
  in a "control" room, separated from the "experiment" room where the
  patient and the rest of the equipment reside. The patient is not
  enclosed in a Faraday cage, but the 60 Hz noise from the power line
  is filtered out by the EEG recorder.
  
Visual stimuli

  In the whole experiment, three visual stimuli are used. All consist
  of white dots on a black background.
  
  The "SD" (single dot) stimulus is one stationary dot at the center
  of the screen.
  
  The "HM" (human, moving) stimulus is a cloud of dots marking the
  articulations, head, and extremities or an (invisible) human figure.
  The dots are moving as if the human was walking on a treadmill, left
  to right.
  
  The "HS" (human, stationary) stimulus is a single stationary frame
  of the "HM" movie.

Experiment and data colection protocol
 
  By SESSION we mean one instance of the experiment, executed with one
  patient.

  The 19 EEG electrodes are installed on the patient scalp at the
  beginning of the SESSION. Then a continuous EEG recording of those
  19 electrodes is made, until the SESSION ends. Then the EEG
  electrodes are removed.

  A SESSION contains two PHASES, "DBS off" and "DBS on". The PHASES
  alternate with three SETUP intervals, when miscellaneous activities
  happen, such as experimenters entering the room to turn the DBS on
  or off.

  Each SETUP interval takes about 120-150 seconds. During each SETUP,
  the screen shows the "SD" (single dot) stimulus.  The
  the SBS signal blinks between 0.00 and -0.26 V, with each full period
  lasting about 3.6 s. Lights may be on during part of
  each SETUP.

  During each PHASE, the room lights are off and the experimenters are
  in the "control" room.

  Each PHASE consists of three BLOCKS, intercalated with two REST
  periods.

  Each REST lasts about 30 seconds. During a REST, the screen shows
  the "SD" (single dot) stimulus. The SBS signal is steady at about
  -0.10 V ("medium" value).

  Each BLOCK consists of 10 PROBES intercalated with 9 GAPS.

  Each GAP is just like a REST, except that it lasts only about 3 s.

  Each PROBE lasts about 30 s. During each PROBE, the screen shows
  either the "HS" (human, stationary) or the "HM" (human, moving)
  stimulus. The SBS signal is 0.00 V and -0.26 V, respectively.
  
Manual cleanup

  Before further proecssing, the SBS channel was cleaned up
  by setting it to 0.5 during the SETUP intervals, and 
  otherwise mapping values 0.00 V, -0.10 V, and -0.26 V (or
  close to them) to 0.0, 0.5, and 1.0, respectively.

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Explicando sobre o canal do marcador,

O link dele é https://1drv.ms/u/s!Anv9nV6BNVjvgbl9xWu3hjyfnK20Ew?e=XEjHbC

Quando ele pisca em alta frequencia é um intervalo de repouso inicial ou final, não
sendo parte do experimento propriamente, mas indicando quando ele começa. A duração
esperada é de 2min-2:30min

intervalos de 30s com a tensão alta indicam o estímulo homem andando e com a tensão
baixa indicam homem parado.

entre esses estímulos há intervalos de 3s de tensão média, que são momentos de
fixação (repouso curto)
após 10 estímulos há um intervalo de 30s também com tensão média, que são os
momentos de repouso entre os blocos.

pode-se notar que o experimento começa e termina uma vez (extremidades marcadas
pelos pulsos de alta frequencia) (1o run) e então existe um período (alguns minutos,
não sei precisar) no qual o dbs está sendo ligado antes de refazer o experimento (2o
run).