Abstract accepted - Learning and Plasticity Meeting

We are pleased to announce that our abstracts were accepted for the poster presentation at the Learning and Plasticity Meeting, taking place on April 6-9 2025 at the Äkäslompolo village.

Abstract 1: “State-of-the-Art in Human Rapid Plasticity Research: A Scoping Review”

Toms Voits, Gaia Olivo & Martin Lövdén

Background: Acquisition of novel skills has been shown to drive morphological changes in the human brain. While the initial findings seemed to suggest neuroplastic changes to occur over a relatively longer period of time (i.e., weeks/months), accumulating evidence now points toward a much shorter timeframe for neuroplastic changes to manifest. Studies have shown that morphological changes can be detected on the scale of days, or even minutes. Yet, a knowledge gap remains in terms of consolidating this emerging literature into a unified framework. With the present contribution, we aim to provide a broad, state-of-the-art scoping review on rapid plasticity research, providing a comprehensive summary of current knowledge, trends and gaps in the field.  Methods: We conducted a search across three relevant research databases (PubMed, APA PsycInfo, Scopus) using a combination of plasticity-related, imaging-related, and time-related search terms and restricting it to papers published within the last 10 years. This search yielded a total of 2847 entries to be screened following duplicate removal. We will screen these entries to only include peer-reviewed articles in English that report primary research on human subjects. Results: This contribution is a work in progress. Preliminary results will be presented during the LaP meeting. Conclusions: We anticipate only a relatively small subset of papers will survive the screening process as we expect only the minority of included entries to conform to our inclusion criteria. If we are on the right track, however, we expect to show a critical mass of longitudinal research reinforcing the notion of plasticity as a rapidly occurring phenomenon in the human brain, detectable even after brief periods of training and/or learning. 

Abstract 2: “Divergence between estimates of short-term grey matter volume changes over time in images acquired with MPRAGE vs. MP2RAGE”

Sean Arthur Cully, Benjamín Garzón, Gunther Helms, Martin Lövdén & Gaia Olivo

Background: Different magnetic resonance imaging (MRI) sequences can produce divergent estimates of brain morphology, resulting in variable measurements of e.g. grey matter volume (GMV). For example, MP2RAGE sequences compared to MPRAGE may reduce noise, minimise artefacts, and improve contrast resulting in cleaner, more consistent brain images with enhanced tissue differentiation. However, many standard neuroimaging preprocessing pipelines are not optimised for MP2RAGE sequences, potentially resulting in reduced accuracy. Here, we examined the differences in estimates of GMV changes between repeated MPRAGE and MP2RAGE sequences acquired from the same 7T MRI scanner and a standard preprocessing pipeline. Methods: This study utilised data from a longitudinal randomised motor skill learning MRI. 63 participants were scanned up to seven times weekly using a structural MP2RAGE sequence while performing simultaneous finger presses with their nondominant (left) hand. Participants were randomised into an experimental group instructed to practise the motor task at home between sessions and a control group, but no meaningful volumetric differences were identified between groups. MPRAGE sequences were reconstructed from the MP2RAGE data. In the current analysis, data from both MRI sequences were preprocessed using the CAT12 longitudinal pipeline optimised for detecting short-term changes. We used a multivariate Bayesian regression model to simultaneously estimate the Sequence x Time interaction effect on GMV estimates in 5 regions of interest (ROI) in the right primary and supplementary motor cortices and bilateral caudate and putamen. Results: The 95% highest density credible intervals (HDCI) of the Sequence x Time interactions were entirely negative for the right pre- and postcentral gyri and the medial segment of the right precentral gyrus. The 95% HDCIs were mostly negative for the medial segment of the postcentral gyrus and the supplementary motor cortex. This indicates that GMV estimates in these cortical ROIs increased over time when they were extracted from MP2RAGE images and decreased over time when they were extracted from MPRAGE images. The 95% HDCIs for the subcortical ROIs were smaller in magnitude and centred closer to zero, indicating that very small or essentially null effects were among the most likely. Conclusion: Our results indicate that the choice of MRI acquisition sequence may affect estimates of adaptive changes in GMV over relatively short time frames, potentially even changing the sign of the estimates of short-term plastic changes. More work is needed to determine to what extent this depends on the choice of preprocessing pipeline.