Biology subjects

Bauernfeind, A. L.

Publications and source records attributed to Bauernfeind, A. L..

3 recordsLinked to original sources

bioRxiv2025

Transcriptomic changes across subregions of the primate cerebellum support the evolution of uniquely human behaviors

BackgroundCompared to other primates, humans display unique behaviors including language and complex tool use. These abilities are made possible in part by the cerebellum. This region of the hindbrain, comprising the flocculus, vermis, and lateral hemispheres, has expanded throughout primate evolution, particularly in great apes. Given the cerebellums architecture--differing in connectivity, neuron content, and functions across subregions--examining subregional differences is crucial to understanding its evolutionary trajectory. ResultsWe performed bulk RNA-seq across samples from six primate species, representing 40-50 million years of evolutionary history, across four subregions of the cerebellum (vermis, flocculus, right lateral hemisphere, left lateral hemisphere). We analyzed changes in gene expression with respect to evolutionary relationships via the Ornstein-Uhlenbeck model and found that, on average, 8.5% of orthologous genes are differentially expressed in humans relative to other non-human primates. Subregion-specific gene expression patterns reveal that the primate lateral hemispheres exhibit significant differences in synaptic activity and glucose metabolism, which in turn are highly implicated in neural processing. ConclusionsThis study provides a novel perspective on gene expression divergences across cerebellar subregions in multiple primate species, offering valuable insights into the evolution of this brain structure. Our findings reveal distinct subregional transcriptomic patterns, with the lateral hemispheres emerging as key sites of divergence across the six primate species. The enrichment of genes related to synaptic activity, glucose metabolism, locomotion, and vocalization highlights the cerebellums crucial role in supporting the neural complexity underlying uniquely human and other species-specific primate behaviors.

genomics↗

bioRxiv2021

Tempo and mode of gene expression evolution in the brain across Primates

Primate evolution has led to a remarkable diversity of behavioral specializations and pronounced brain size variation among species 1,2. Gene expression provides a promising opportunity for studying the molecular basis of brain evolution, but it has been explored in very few primate species to date e.g. 3,4. To understand the landscape of gene expression evolution across the primate lineage, we generated and analyzed RNA-Seq data from four brain regions in an unprecedented eighteen species. Here we show a remarkable level of variation in gene expression among hominid species, including humans and chimpanzees, despite their relatively recent divergence time from other primates. We found that individual genes display a wide range of expression dynamics across evolutionary time reflective of the diverse selection pressures acting on genes within primate brain tissue. Using our sample that represents an unprecedented 190-fold difference in primate brain size, we identified genes with variation in expression most correlated with brain size and found several with signals of positive selection in their regulatory regions. Our study extensively broadens the context of what is known about the molecular evolution of the brain across primates and identifies novel candidate genes for study of genetic regulation of brain development and evolution.

evolutionary biology↗

bioRxiv2017

Maternal SSRI treatment during offspring development results in long-term behavioral, cellular, and neuroimaging disruptions

Serotonergic dysregulation is implicated in psychiatric disorders, including autism spectrum disorders (ASD). Epidemiological studies suggest selective serotonin reuptake inhibitor (SSRI) treatment during pregnancy may increase ASD risk in offspring, however it is unclear from these studies whether ASD susceptibility is related to the maternal diagnosis or if treatment poses additional risk. Here, we exposed mouse dams to fluoxetine and characterized the offspring to isolate possible effects of SSRI exposure on ASD-relevant behaviors. We demonstrate social communication and interaction deficits and repetitive behaviors, with corresponding dendritic morphology changes in pertinent brain regions. Also, using a novel application of optical intrinsic signal imaging, we show altered stimulus-evoked cortical response and region-specific decreases in functional connectivity. These findings indicate drug exposure alone is sufficient to induce long-term behavioral, cellular, and hemodynamic-response disruptions in offspring, thus contributing to our understanding of ASD pathogenesis, risk and mechanism, as well as the developmental role of serotonin.

neuroscience↗