Doner, S. | Search bioRxiv

bioRxiv2025

Newly trained navigation and verbal memory skills elicit changes in task-related networks but not brain structure

Training cognitive skills, such as remembering a list of words or navigating a new city, has important implications for everyday life. Yet, understanding what brain changes underlie the acquisition of complex cognitive skills remains unresolved. Here, we developed and validated intensive multiweek interventions in which participants were randomly assigned training in either navigation or verbal memory. Healthy young participants (N=75) underwent structural and functional imaging prior to and following the training. Based on pre-registered and exploratory analyses, we did not find any evidence for changes to gross hippocampal or hippocampal subfield volume, cortical brain volume, or white matter connectivity due to the training. In contrast, network-based analyses suggested changes in task-related informational connectivity, which occurred primarily between cortical areas and mostly involved putative cognitive control networks. These results suggest that cognitive interventions target more transient configurations in network connectivity rather than more durable structural changes.

neuroscience↗

bioRxiv2023

Age-related spatial memory differences are correlated with neural remapping in CA1 of the human hippocampus

Older adults show declines in spatial memory, although the extent of these alterations is not uniform across the healthy older population. Here, we investigate the stability of neural representations for the same and different spatial environments in a sample of younger and older adults using high-resolution functional magnetic resonance imaging (fMRI) of the medial temporal lobe. Older adults showed, on average, lower neural pattern similarity for retrieving the same environment and more variable neural patterns compared to young adults. We also found a positive association between spatial distance discrimination and the distinctiveness of neural patterns between environments. Our analyses suggested that one source for this association was the extent of informational connectivity to CA1 from other subfields, which was dependent on age, while another source was the fidelity of signals within CA1 itself, which was independent of age. Together, our findings suggest both age-dependent and independent neural contributions to spatial memory performance. Significance StatementSpatial memory declines with age, although some older adults show little cognitive decline, even into their 80s. One important lead for age-related changes comes from electrophysiological studies of older rats, who have less stable neural representations for a spatial environment, termed "place cells." Using high-resolution fMRI targeting the human hippocampus, we demonstrate that older adults also have less stable neural representations within the same environment. Our results reveal, however, that there are both age and performance dependent differences driving these effects. While older adults, on average, showed alterations in information flow within the hippocampal circuit, better performing individuals showed more differentiated neural representations regardless of age. Together, these findings provide novel insight into the impact of age on spatial memory.

neuroscience↗