Sketches of Ganzfeld phenomena.

<p>Above: drawn by <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030830#pone.0030830-Purkinje1" target="_blank">[1]</a> these depict (right to left) “primary patterns”, “snail-rectangle” and “eight-beam”. Below: sketches from participants tested by Becker and Elliott (unpublished) of, (right to left) “hexagons”, “spirals” and “points”. The photograph shows goggles made from Ping-Pong balls (Reprinted from Consciousness and Cognition, Carsten Allefeld, Peter Pütz, Kristina Kastner, Jiří Wackermann, Flicker-light induced visual phenomena: Frequency dependence and specificity of whole percepts and percept features, in press/corrected proof, (2011), with permission from Elsevier).</p

Frequency components derived from discrete Fourier analysis of the averaged component time series.

<p>The left y-axis gives normalized power while the right y-axis gives actual power. The dotted lines indicate standard errors. In (a) analysis of circles and points reveals peaks at theta (6 Hz) and mid gamma-band (46 and 48 Hz) frequencies. Subjectively, both points and circles appear at a set of independent loci that are apparently randomly distributed across the visual field. They are characterized by particularly high power in both theta and gamma bands which may index an as yet unresolved process of pattern completion. In (b), and by contrast, spirals refer to a spatially contiguous and so relatively well defined visual pattern. Fourier analysis reveals these reports to be accompanied by very low power distributed across multiple peak frequencies; including a major peak at 4 Hz. Fourier analysis carried out on the component time series for reports “spirals” for each participant separately reveals power spectra with multiple peaks tabled in (c). All peaks bar one are multiples (harmonics) of a fundamental frequency of 4 Hz, indicating subjective experience of spirals to be accompanied by a lattice of harmonic activity in the EEG.</p

Percentage of ‘simultaneous’ responses across SOA.

<p>Bias-corrected means (SD) of ‘simultaneous’ responses (%) across stimulus onset asynchronies (SOA) of ASD and TD participants.</p

Correlation of thresholds with symptoms.

<p>ADI-B scores (left) and non-verbal ADI-B sub-score only (right) in the ASD group over perceptual simultaneity thresholds. The data point corresponding to the threshold derived from a curve fit with a goodness of fit <i>R²</i>>90 is depicted in grey. Note that there are two overlapping data points (31, 10).</p

Demographic data.

<p>Means, standard deviations, and ranges of age (years:months), verbal IQ (VIQ), performance IQ (PIQ), and full IQ (FIQ) of participants with an autism spectrum disorder (ASD) and typically-developing (TD) participants. ADI-R Social Interaction Domain (ADI-A), ADI-R Communication Domain (ADI-B), ADI-R Repetitive Behaviours Domain (ADI-C), ADOS-G Communication Domain (ADOS-A), ADOS-G Reciprocal Social Interaction Domain (ADOS-B), and ADOS-G Stereotyped Behaviours and Restricted Interests Domain (ADOS-C) of participants with ASD.</p

T2* approximation of the SE SVS data acquired at 3 T and at 7 T.

<p>The linear regression fits (red) are shown for single PMC ln|FID|’s (blue) for representative participants at 3 T (A) and at 7 T (B). Optimal linearization lengths are 0.18 s at 3 T (t = 41.6, p<0.001), and 0.052 s at 7 T (t = 16.7, p<0.001).</p

Illustration of the GE EPI and SE SVS ROIs.

<p>A GE EPI activation map and a single-voxel PMC ROI (blue) of a representative participant are shown on sagittal, transverse, and coronal planes of this participant’s structural scan. The PMC SE SVS ROI (size approximately 1×1×1 cm³) was defined to cover the voxels that exhibited a significant positive BOLD response to the left hand finger tapping. The GE EPI ROI was restricted to the SE SVS ROI.</p

Percent signal change (Δ%), CNR, t-statistics for the GE EPI and for the SE SVS acquisitions at 3 T and at 7 T.

<p>Percent signal change (Δ%), CNR, t-statistics for the GE EPI and for the SE SVS acquisitions at 3 T and at 7 T.</p

Sequence of data acquisition.

<p>GE – gradient-echo, EPI – echo-planar imaging, SE – spin-echo, SVS – single voxel spectroscopy, PMC – primary motor cortex, VC – visual cortex, NF – neurofeedback, loc – localizer.</p

Performance comparison between GE EPI and SE SVS time courses at 3

<p>We compared the time course quality of the PMC (1^st column), the PMC NF (2^nd column), and the VC (3^rd column) in terms of their percent signal change (Δ%; panel A), contrast-to-noise ratio (CNR, panel B), and t-statistics (t-value, panel C). This was done separately for data acquired with GE EPI (blue bars) and SE SVS (red bars), and separately for 3 T and 7 T acquisitions. At 3 T, the higher SE SVS CNR and t-value were indicated with red arrows. At 7 T, the higher GE EPI Δ% was indicated with green arrows. Error bars represent the standard error of the mean; asterisks denote statistical significance (p<0.05).</p