Biology subjects

Murayama, K.

Publications and source records attributed to Murayama, K..

3 recordsLinked to original sources

bioRxiv2018

Cross-Lagged Panel Model in Medical Research: A Cautionary Note

Longitudinal designs provide a strong inferential basis for uncovering reciprocal effects or causality between variables. For this analytic purpose, a cross-lagged panel model (CLPM) has been widely used in medical research, but the use of the CLPM has recently been criticized in methodological literature because parameter estimates in the CLPM conflate between-person and within-person processes. The aim of this study is to present some alternative models of the CLPM that can be used to examine reciprocal effects, and to illustrate potential consequences of ignoring the issue. A literature search, case studies, and simulation studies are used for this. We examined more than 300 medical papers published since 2009 that applied cross-lagged longitudinal models, finding that in all studies only a single model (typically, the CLPM) was performed and potential alternative models were not considered to test reciprocal effects. In 49% of the studies, only two time points were used, which makes it impossible to test such alternative models. Case studies and simulation studies showed that the CLPM often has worse model fit and markedly different estimates of cross-lagged parameters than alternative models, suggesting that research that relies on the CLPM only may draw erroneous conclusions regarding the presence, predominance, and sign of reciprocal effects as well as about causality.

scientific communication and education↗

bioRxiv2018

Hunger for Knowledge: How the Irresistible Lure of Curiosity is Generated in the Brain

Curiosity is often portrayed as a desirable feature of human faculty. However, curiosity may come at a cost that sometimes puts people in a harmful situation. Here, with a set of behavioural and neuroimaging experiments using stimuli that strongly trigger curiosity (e.g., magic tricks), we examined the psychological and neural mechanisms underlying the motivational effect of curiosity. We consistently demonstrated that across different samples, people were indeed willing to gamble, subjecting themselves to physical risks (i.e. electric shocks) in order to satisfy their curiosity for trivial knowledge that carries no apparent instrumental value. Also, this influence of curiosity shares common neural mechanisms with that of extrinsic incentives (i.e. hunger for food). In particular, we showed that acceptance (compared to rejection) of curiosity/incentive-driven gambles was accompanied by enhanced activity in the ventral striatum (when curiosity was elicited), which extended into the dorsal striatum (when participants made a decision).

neuroscience↗

bioRxiv2018

Inter-slice leakage and intra-slice aliasing in simultaneous multi-slice echo-planar images

Simultaneous multi-slice (SMS) imaging is a popular technique for increasing acquisition speed in echo-planar imaging (EPI) fMRI. However, SMS data are prone to motion sensitivity and slice leakage artefacts, which spread signal between simultaneously acquired slices. Relevant to motion sensitivity, artefacts from moving anatomic structures propagate along the phase-encoding (PE) direction. This is particularly relevant for eye movement. As signal from the eye is acquired along with signal from simultaneously excited slices during SMS, there is potential for signal to spread in-plane and between spatially remote slices. After identifying an artefact temporally coinciding with signal fluctuations in the eye and spatially distributed in correspondence with multiband slice acceleration and parallel imaging factors, we conducted a series of small experiments to investigate eye movement artefacts in SMS data and the contribution of PE direction to the invasiveness of these artefacts. Five healthy adult volunteers were scanned during a blinking task using a standard SMS-EPI protocol with posterior-to-anterior (P>>A), anterior-to-posterior (A>>P) or right-to-left (R>>L) PE direction. The intensity of signal fluctuations (artefact severity) was measured at expected artefact positions and control positions. We demonstrated a direct relationship between eye movements and artefact severity across expected artefact regions. Within-brain artefacts were apparent in P>>A- and A>>P-acquired data but not in R>>L data due to the shift in artefact positions. Further research into eye motion artefacts in SMS data is warranted but researchers should exercise caution with SMS protocols. We recommend rigorous piloting of SMS protocols and switching to R>>L/L>>R PE where feasible.

neuroscience↗