Biology subjects

Gunnink, H.

Publications and source records attributed to Gunnink, H..

3 recordsLinked to original sources

bioRxiv2025

Cholinergic disruption of state-dependent retrosplenial layer 1 activity causes temporal associative memory deficit under stress

Memory functions rely on discrete patterns of neuronal activity emerging from individual neurons, their interconnected circuits, and their alignment with global brain states. We show that such patterns are generated by layer 1 inhibitory neurons in the ventral retrosplenial cortex (vRSPL1), whose activity correlated with immobility and specifically contributed to the formation of temporal associative memories. This state-dependent activity was subject to stress-induced cholinergic modulation through muscarinic 1 receptor (M1R) signaling, leading to selective impairments in temporal but not contextual associative memory. Slice studies showed that these effects were likely due to M1R-mediated inhibition of vRSPL1 neurons, transiently disrupting their local connectivity as well as responsiveness to afferent input. Together, we demonstrate a mechanism by which vRSPL1 activity aligned to immobility coordinate the formation of temporal associations. Through its sensitivity to stress-related cholinergic modulation, this mechanism presents vulnerability to traumatic amnesia, especially for temporal details of episodic memories.

neuroscience↗

bioRxiv2023

The genetic legacy of the expansion of Bantu-speaking peoples in Africa

With the largest genomic dataset to date of Bantu-speaking populations, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we shed fresh light on the expansion of peoples speaking Bantu languages that started [~]4000 years ago in western Africa. We have genotyped 1,740 participants, including 1,487 Bantu speakers from 143 populations across 14 African countries, and generated whole-genome sequences from 12 Late Iron Age individuals. Our results show that Bantu speakers received significant gene-flow from local groups in regions they expanded into. We show for the first time that genetic diversity amongst Bantu-speaking populations declines with distance from western Africa, with current-day Zambia and the DRC as possible crossroads of interaction. Using spatially explicit methods and correlating genetic, linguistic and geographical data, we provide cross-disciplinary support for a serial founder migration model. Finally, we discuss the utility of our dataset as an exhaustive modern-day African comparative dataset for ancient DNA studies. These new findings and data will be important to a wide range of disciplines from science and humanities as well as to the medical sector studying human genetic variation and health in African and African-descendant populations. One-sentence summaryA comprehensive genetic analysis of the expansion of people speaking Bantu languages reveals a complex history of serial founder events, variable levels of contact with local groups, and spread-over-spread events.

evolutionary biology↗

bioRxiv2020

Genetic-substructure and complex demographic history of South African Bantu speakers

South Eastern Bantu-speaking (SEB) groups constitute more than 80% of the population in South Africa. Despite clear linguistic and geographic diversity, the genetic differences between these groups have not been systematically investigated. Based on genome-wide data of over 5000 individuals, representing eight major SEB groups, we provide strong evidence for fine-scale population structure that broadly aligns with geographic distribution and is also congruent with linguistic phylogeny (separation of Nguni, Sotho-Tswana and Tsonga speakers). Although differential Khoe-San admixture plays a key role, the structure persists after Khoe-San ancestry-masking. The timing of admixture, levels of sex-biased gene flow and population size dynamics also highlight differences in the demographic histories of individual groups. The comparisons with five Iron Age farmer genomes further support genetic continuity over [~]400 years in certain regions of the country. Simulated trait genome-wide association studies further show that the observed population structure could have major implications for biomedical genomics research in South Africa.

genomics↗