Prefrontal Inter-brain Synchronization Reflects Convergence and Divergence of Flow Dynamics in Collaborative Learning: A Pilot Study.

Flow is a highly motivated and affectively positive state in which a person is deeply engaged in an activity and feeling enjoyment from it. In collaborative activities, it would be optimal if all participants were in a state of flow. However, flow states fluctuate amongst individuals due to differences in the dynamics of motivation and cognition. To explore the possibility that inter-brain synchronization can provide a quantitative measure of the convergence and divergence of collective motivational dynamics, we conducted a pilot study to investigate the relationship between inter-brain synchronization and the interpersonal similarity of flow state dynamics during the collaborative learning process. In two English as a Foreign Language (EFL) classes, students were divided into groups of three-four and seated at desks facing each other while conducting a 60-min group work. In both classes, two groups with four members were randomly selected, and their medial prefrontal neural activities were measured simultaneously using wireless functional near-infrared spectroscopy (fNIRS) devices. Later the participants observed their own activities on recorded videos and retrospectively rated their subjective degree of flow state on a seven-point scale for each 2-min period. For the pairs of students whose neural activities were measured, the similarity of their flow experience dynamics was evaluated by the temporal correlation between their flow ratings. Prefrontal inter-brain synchronization of the same student pairs during group work was evaluated using wavelet transform coherence. Statistical analyses revealed that: (1) flow dynamics were significantly more similar for the student pairs within the same group compared to the pairs of students assigned across different groups; (2) prefrontal inter-brain synchronization in the relatively short time scale (9.3-13.9 s) was significantly higher for the within-group pairs than for the cross-group pairs; and (3) the prefrontal inter-brain synchronization at the same short time scale was significantly and positively correlated with the similarity of flow dynamics, even after controlling for the effects of within- vs. cross-group pair types from the two variables. These suggest that inter-brain synchronization can indeed provide a quantitative measure for converging and diverging collective motivational dynamics during collaborative learning, with higher inter-brain synchronization corresponding to a more convergent flow experience.

Preferential detection of pro-carboxypeptidase R by enzyme-linked immunosorbent assay.

We generated two monoclonal antibodies (mAbs), 2A16 and 10G1, against pro-carboxypeptidase R (proCPR), also known as thrombin activatable fibrinolysis inhibitor (TAFI). By use of these mAbs, we developed a sandwich enzyme-linked immunosorbent assay (ELISA) system to detect proCPR. Since the amount of the antigen detectable by the ELISA was essentially the same in fresh plasma and serum incubated at 37 C for 1 hr, we concluded that the ELISA system detected not only proCPR, but also inactivated CPR generated from proCPR. However, an appreciable amount of proCPR remained unactivated in serum. For extensive activation of proCPR in plasma, thrombin and thrombomodulin complexes (TTM) can be used together with CaCl2. Following extensive conversion of proCPR to CPR by T-TM and CaCl2, converting plasma to serum (T-TM serum), antigenicity became undetectable by ELISA. Further analysis revealed that 2A16 reacts only with proCPR although 10G1 reacts with proCPR, active CPR and inactivated CPR. Therefore, we concluded that the ELISA system preferentially detects proCPR and not CPR. Our sandwich ELISA system utilizing 2A16 and 10G1 provides a suitable method for detecting proCPR and can be used to determine levels of proCPR in plasma samples from patients.

Subtype analysis of neuropathologically diagnosed patients in a Japanese geriatric hospital.

Dementia is a social problem in Japan, as it is in other countries. Recently, there has been an increase in the number of patients with Alzheimer-type dementia (ATD) in the population. We analyzed 239 cases of patients autopsied at Fukushimura Hospital over a 10-year period. Clinicopathologically, 66% of these cases (158 cases) presented with dementia symptoms. The predominant form of illness was ATD. We found dementia with Lewy bodies (DLB) to be as frequent as vascular dementia (VD). Although the numbers were small, limbic neurofibrillary tangle dementia (LNTD) and Pick's disease (PiD) followed a clinical course typical of these diseases. On the other hand, senile dementia of the Alzheimer's type (SDAT) and the common form of neocortical type DLB (diffuse Lewy body disease; DLBD) were difficult to distinguish from each other. We attempted to uncover differences between these dementias in terms of how they affect male and female patients. The clinical course of the male patients with the common form of neocortical type DLB was more or less typical, while that of the female patients was not.

CD59 blocks not only the insertion of C9 into MAC but inhibits ion channel formation by homologous C5b-8 as well as C5b-9.

Activation of the complement system on the cell surface results in the insertion of pore forming membrane attack complexes (MAC, C5b-9). In order to protect themselves from the complement attack, the cells express several regulatory molecules, including the terminal complex regulator CD59 that inhibits assembly of the large MACs by inhibiting the insertion of additional C9 molecules into the C5b-9 complex. Using the whole cell patch clamp method, we were able to measure accumulation of homologous MACs in the membrane of CD59(-) human B-cells, which formed non-selective ion channels with a total conductance of 360 +/- 24 pS as measured at the beginning of the steady-state phase of the inward currents. C5b-8 and small-size MAC (MAC containing only a single C9) can also form ion channels. Nevertheless, in CD59(+) human B-cells in spite of small-size MAC formation, an ion current could not be detected. In addition, restoring CD59 to the membrane of the CD59(-) cells inhibited the serum-evoked inward current. The ion channels formed by the small-size MAC were therefore sealed, indicating that CD59 directly interfered with the pore formation of C5b-8 as well as that of small-size C5b-9. These results offer an explanation as to why CD59-expressing cells are not leaky in spite of a buildup of homologous C5b-8 and small-size MAC. Our experiments also confirmed that ion channel inhibition by CD59 is subject to homologous restriction and that CD59 cannot block the conductivity of MAC when generated by xenogenic (rabbit) serum.