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Fromm, A.

Publications and source records attributed to Fromm, A..

3 recordsLinked to original sources
bioRxiv2026

Brain Regions Involved in Object-Location Memory Across the Human Lifespan: A Systematic Review and Activation Likelihood Estimation Meta-Analysis of Task-Based fMRI

BackgroundThe ability to remember object locations in real life is a fundamental cognitive process that supports goal-directed behavior and is particularly vulnerable to aging and neurodegenerative disease. Despite a growing body of functional magnetic resonance imaging (fMRI) research on object-location memory (OLM), the neural substrates of establishing and retrieving location information are largely unknown. ObjectiveThis systematic review and coordinate-based meta-analysis aimed to identify brain regions consistently activated during OLM in healthy adults, primarily for encoding and - on an exploratory basis - for retrieval, and to characterize age-related differences in OLM-related neural activity. MethodsA systematic search was conducted across three databases (PubMed, PsycInfo, Cochrane Library) up to February 2026. Studies employing task-based fMRI during the encoding and retrieval of object-location associations in healthy adults were eligible. Age-related differences in OLM-related brain activity were examined via narrative synthesis. An activation likelihood estimation (ALE) meta-analysis was performed on studies reporting stereotactic peak coordinates. The review was pre-registered on PROSPERO (CRD420251023695). ResultsTwenty-one studies comprising 637 participants were included in the systematic review, with 12 studies being eligible for the encoding ALE meta-analysis. The retrieval ALE meta-analysis was not possible due to the limited number of included studies and reported foci. The systematic review indicated that OLM encoding consistently recruited bilateral fusiform gyri and parahippocampal cortices, with additional engagement of parietal and prefrontal regions across individual studies, whereas OLM retrieval recruited mainly the hippocampus and precuneus. The coordinate-based ALE meta-analysis revealed two significant clusters of activation during OLM encoding: a left-lateralized cluster encompassing the fusiform gyrus, parahippocampal gyrus, and inferior temporal gyrus (peak MNI: -28, -38, -16), and a right-hemisphere cluster spanning the parahippocampal gyrus and fusiform gyrus (peak MNI: 30, -46, -16). Age-related differences, based on a small number of studies with direct age comparison, pointed toward reduced activity in posterior cortical regions coupled with increased activity in prefrontal and midline regions. Additionally, younger adults showed greater hippocampal activation for successful than unsuccessful spatial retrieval, whereas older adults showed the opposite pattern. ConclusionThe systematic review and meta-analysis identify the fusiform gyri and parahippocampal cortices as the most reliably activated regions during OLM encoding, locating OLM formation primarily within the ventral visual-to-medial-temporal processing stream. Retrieval additionally engaged the hippocampus and precuneus, consistent with their established roles in episodic memory. Age-related differences included reduced posterior cortical encoding activity in older adults, a reversal of the hippocampal activation pattern during retrieval, and weaker suppression of midline regions during task performance. The identified encoding pathway may inform targeted network-level interventions such as non-invasive brain stimulation to counteract cognitive decline in aging and neurodegenerative disease. Highlights- First systematic review and coordinate-based meta-analysis of task-based fMRI during encoding and retrieval of object-location memories (OLMs). - Activation likelihood estimation (ALE) identified bilateral fusiform gyrus and parahippocampus as the most consistent encoding regions, supporting a ventral-dominant input pathway. - Hippocampus and precuneus were the most consistent OLM retrieval regions, suggesting an encoding-retrieval dissociation. - Age-related encoding differences centered on reduced fusiform and parahippocampal subsequent-memory effects, with an altered anterior-hippocampal response in older adults.

neuroscience↗
bioRxiv2025

Mapping the transcriptional landscape of algal resistance to viral infection reveals a core expression program

O_LIAlgal blooms and their demise by viruses drive global-scale ecological processes in the ocean. These blooms form the foundation of marine food webs, regulate microbial communities, and shape biogeochemical cycles. Although algal populations are constantly infected by viruses, resistant subpopulations frequently emerge after the infection. Yet, antiviral molecular mechanisms of marine microalgae are underexplored. C_LIO_LIWe used a model system of the ubiquitous microalga Emiliania huxleyi and its giant virus, E. huxleyi virus (EhV), to study how resistant populations evolve and to identify their transcriptional programs. We generated a detailed temporal transcriptomic dataset during a viral infection, covering the stages of lysis and the recovery of a resistant subpopulation. C_LIO_LIViral infection triggered prominent transcriptome changes to support viral propagation, followed by a unique transcriptional response in resistant cells. Both infected and resistant cells highly expressed innate immune response genes, notably those with Toll/interleukin-1 receptor (TIR) domain. Additionally, resistant cells expressed genes involved in membrane-bound glycan remodeling, sphingolipid metabolism, and nutrient uptake. C_LIO_LIUsing comparative transcriptomics across diverse resistant E. huxleyi strains, we identified a core group of resistance-related genes, providing a set of gene markers to detect this rare phenotype during the host-virus arms race in algal blooms. C_LI

microbiology↗
bioRxiv2023

Homing in on the rare virosphere reveals the native host of giant viruses

Giant viruses (phylum Nucleocytoviricota) are globally distributed in aquatic ecosystems1,2. They play major roles as evolutionary drivers of eukaryotic plankton3 and regulators of global biogeochemical cycles4. Recent metagenomic studies have significantly expanded the known diversity of marine giant viruses1,5-7, but we still lack fundamental knowledge about their native hosts, thereby hindering our understanding of their lifecycle and ecological importance. Here, we aim to discover the native hosts of giant viruses using a novel, sensitive single-cell metatranscriptomic approach. By applying this approach to natural plankton communities, we unraveled an active viral infection of several giant viruses, from multiple lineages, and identified their native hosts. We identify a rare lineage of giant virus (Imitervirales-07) infecting a minute population of protists (class Katablepharidaceae) and revealed the prevalence of highly expressed viral-encoded cell-fate regulation genes in infected cells. Further examination of this host-virus dynamics in a temporal resolution suggested this giant virus controls its host population demise. Our results demonstrate how single-cell metatranscriptomics is a sensitive approach for pairing viruses with their authentic hosts and studying their ecological significance in a culture-independent manner in the marine environment.

microbiology↗