Brain-to-brain (B2B) communication system overview.

<p>On the left, the BCI subsystem is shown schematically, including electrodes over the motor cortex and the EEG amplifier/transmitter wireless box in the cap. Motor imagery of the feet codes the bit value 0, of the hands codes bit value 1. On the right, the CBI system is illustrated, highlighting the role of coil orientation for encoding the two bit values. Communication between the BCI and CBI components is mediated by the internet.</p

View of emitter and receiver subjects with non-invasive devices supporting, respectively, the BCI based on EEG changes driven by motor imagery (left) and the CBI based on the reception of phosphenes elicited by a neuronavigated TMS (right) components of the B2B transmission system.

<p>The successfully transmitted code in the particular scenario shown is a ‘0’: the target and ball are at the bottom of the screen (correctly encoding a 0 through motor imagery of the feet) and the TMS coil is in the orientation not producing phosphenes for this particular participant (subject 2, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105225#pone-0105225-g003" target="_blank">Figure 3</a>), with the handle pointing upwards.</p

Location and orientation of hot spot for phospene production overlaid on MRI image of the head of subject 2 (see Figure 2).

<p>The active direction producing phospenes is highlighted in orange (in red, the orthogonal direction not producing phosphenes).</p

Summary of the kinematic parameter for the patients' group (PG) and control group (CG).

<p>Bars represent the mean of frequency (FREQ), number of inversions of velocity (NIV) and the average maximum velocity (Max Vel) for finger tapping (FT), hand tapping (HT) and forearm pronation-supination (PS). Error bars represent the standard deviation of the mean (SEM). Significant differences after training in the MG are indicated (* p<.05, ** p<.01).</p

Demographic data of each individual of the group of patients.

<p>For each participant, the following data was obtained at the time the patient began the study: The age (years), months since the stroke, the Medical Research Council (MRC) score, the location of the lesion and the Barthel Index.</p

Correlation between changes on the position of the CoG in the mediolateral edge and changes on the number of inversion of velocity (NIV) for hand tapping (HT) from subjects in PG.

<p>Rounded points were considered outlier values after corresponding test and were excluded from the sample.</p

Summary of the plastic changes observed with the cortical maps.

<p>(A) Displacement of the center of gravity (CoG) across time for the affected and unaffected hemisphere in PG. The origin of each arrow represents the baseline coordinates of the CoG. Arrowheads represent the position of the CoG at evaluation 2. Each arrow is colored differently, corresponding to each subject from PG. (B) Displacement of the medial coordinate of the center of gravity (CoGx) of motor mapping representation through time. In the affected hemisphere (left), almost all patients showed a displacement on the mediolateral edge of the CoG to more temporal regions.</p

Example of performance of fast diadochokinetic finger.

<p>Detail of the signal recorded from one marker with the 3D movement-analyzer during finger and hand tapping movements of the affected hand of one representative patient (A) and one control subject (B). The marker was attached on the index finger (finger tapping) and from methacarpophalangeal joint (hand tapping). Time courses of the displacement in cm measured in both evaluations are displayed.</p

Results of ANOVA analysis of each dependent variable concerning diadochokinetic movements performed with the contralateral hand.

<p>Units of each dependent variable are also shown. Notes: FREQ = frequency; VMAX = maximal velocity; NIV = number of inversion of velocity; FT = finger tapping; HT = hand tapping; PS = pronation-supination; deg = degree; s = second.</p

Results of ANOVA analysis of each dependent variable concerning electrophysiological measurements obtained after the stimulation of each hemisphere (affected and unaffected) (* <i>p</i><.05; ⁺.05<<i>p</i><.1; n.s. not significant).

<p>Notes: MEP = peak-to-peak amplitude of the motor evoked potential; RMT = resting motor threshold; AMT = active motor threshold; CoG_x = mediolateral coordinate of the center of gravity; CoG_y = anteroposterior coordinate of the center of gravity; CSP = cortical silent period; µV = microvolts; ms = milliseconds; cm² = squared centimeters.</p