head eeg sensor system  (Welcony)

Journal:

Article Title: Cue-Invariant Networks for Figure and Background Processing in Human Visual Cortex

doi: 10.1523/JNEUROSCI.2741-06.2006

Figure Lengend Snippet: Steady-state responses for three stimulus conditions. Amplitude spectra of one observer are depicted for a representative EEG sensor located over the response maxima [sensors 85 (A, C) and 75 (B) of the Geodesics HydroCell Sensor Net] for three stimulus conditions: figure-only (A), full field (B), and the orientation-defined form (C). Each amplitude spectrumis located over two frames of the stimulus from which it was obtained. SSVEP responses were present at integer multiples of the stimulus frequencies for each stimulus condition. Responses at harmonics of the stimulus frequencies are shown as darkened lines, with corresponding labels (nF1, figure-related; nF2, background-related). The figure-only stimulus condition (A) produced responses at integermultiplesofthe figure frequency tag (3.0, 6.0, 9.0 Hz…). Responses to the full field stimulus condition (B) were present at the harmonics of the full field frequency tag (3.0, 6.0, 9.0 Hz…). The amplitude spectrum resulting from the orientation-defined form stimulus (C) contained responses at harmonics of both the figure (3.0, 6.0, 9.0 Hz…) and the background (3.6, 7.2, 10.8 Hz…) tags as well as at low-order sums and the difference of these two frequencies (0.6, 6.6 Hz…).

Article Snippet: EEG signal acquisition The EEG was collected with a whole-head, 128-channel geodesic EEG system with HydroCell Sensor Nets (Electrical Geodesics, Eugene, OR).

Techniques: Produced

Journal:

Article Title: Cue-Invariant Networks for Figure and Background Processing in Human Visual Cortex

doi: 10.1523/JNEUROSCI.2741-06.2006

Figure Lengend Snippet: Group-averaged responses for the figure (2f1) and background (2f2) are shown for each of the four cue types (A–D) and two attention conditions (E, F). Topographies and current density estimates are shown as 13 subject grand averages for the second harmonic of the figure on the left and the background on the right. Figure responses are lateralized over the occipital cortex for all cues and attention conditions. Background responses are focused on the midline pole and are similar for all cue types and attention conditions. A schematic illustration of each stimulus, the number of observers included in the average, and the response maximum are included for each response distribution. The seven channel locations (Electrical Geodesics HydroCell Sensor Net, channels 59, 65, 71, 72, 75, 76, 90, 91) used to test sensor map differences are superimposed on the two-dimensional maps for the figure-only and full field. They are coded blue for the medial channels (Oz) and green for the lateral channels (P7 and P8).

Article Snippet: EEG signal acquisition The EEG was collected with a whole-head, 128-channel geodesic EEG system with HydroCell Sensor Nets (Electrical Geodesics, Eugene, OR).

Techniques: