Biology subjects

Dolen, G.

Publications and source records attributed to Dolen, G..

6 recordsLinked to original sources

bioRxiv2023

Amygdala AVPR1A mediates susceptibility to chronic social isolation in females

Females are more sensitive to social exclusion, which could contribute to their heightened susceptibility to anxiety disorders. Chronic social isolation stress (CSIS) for at least 7 weeks after puberty induces anxiety-related behavioral adaptations in female mice. Here, we show that Arginine vasopressin receptor 1a (Avpr1a)-expressing neurons in the central nucleus of the amygdala (CeA) mediate these sex-specific effects, in part, via projections to the caudate putamen. Loss of function studies demonstrate that AVPR1A signaling in the CeA is required for effects of CSIS on anxiety-related behaviors in females but has no effect in males or group housed females. This sex-specificity is mediated by AVP produced by a subpopulation of neurons in the posterodorsal medial nucleus of the amygdala that project to the CeA. Estrogen receptor alpha signaling in these neurons also contributes to preferential sensitivity of females to CSIS. These data support new therapeutic applications for AVPR1A antagonists in women.

neuroscience↗

bioRxiv2021

Prenatal immune stress induces a prolonged blunting of microglia activation that impacts striatal connectivity

Recent studies suggested that microglia, the primary brain immune cells, can affect circuit connectivity and neuronal function1-3. Microglia infiltrate the neuroepithelium early in embryonic development and are maintained in the brain throughout adulthood4,5. Several maternal environmental factors, such as aberrant microbiome, immune activation, and poor nutrition, can influence prenatal brain development6-8. Nevertheless, it is unknown how changes in the prenatal environment instruct the developmental trajectory of infiltrating microglia, which in turn affect brain development and function. Here we show that after maternal immune activation (MIA) microglia from the offspring have a long-lived decrease in immune reactivity (blunting) across the developmental trajectory. The blunted immune response was concomitant with changes in the chromatin accessibility and reduced transcription factor occupancy of the open chromatin. Single cell RNA sequencing revealed that MIA does not induce a distinct subpopulation but rather decreases the contribution to inflammatory microglia states. Prenatal replacement of MIA microglia with physiological infiltration of naive microglia ameliorated the immune blunting and restored a decrease in presynaptic vesicle release probability onto dopamine receptor type-two medium spiny neurons, indicating that aberrantly formed microglia due to an adverse prenatal environment impacts the long-term microglia reactivity and proper striatal circuit development.

neuroscience↗

bioRxiv2021

The lesser Pacific striped octopus, Octopus chierchiae: an emerging laboratory model for the study of octopuses

Cephalopods have the potential to become useful experimental models in various fields of science, particularly in neuroscience, physiology, and behavior. Their complex nervous systems, intricate color- and texture-changing body patterns, and problem-solving abilities have attracted the attention of the biological research community, while the high growth rates and short life cycles of some species render them suitable for laboratory culture. Octopus chierchiae is a small octopus native to the central Pacific coast of North America whose predictable reproduction, short time to maturity, small adult size, and ability to lay multiple egg clutches (iteroparity) make this species ideally suited to laboratory culture. Here we describe novel methods for culture of O. chierchiae, with emphasis on enclosure designs, feeding regimes, and breeding management. Our results demonstrate the feasibility of multigenerational culture of O. chierchiae. Specifically, O. chierchiae bred in the laboratory grows from a 3.5-millimeter mantle length at hatching to an adult mantle length of approximately 20-30 millimeters in 250-300 days, with 14-15% survivorship to over 400 days of age in first and second generations. O. chierchiae sexually matures at around an estimated six months of age and, unlike most octopus species, can lay multiple clutches of eggs, approximately every 30-90 days. Eggs are large and hatchlings emerge as direct developing octopuses. Based on these results, we propose that O. chierchiae possesses both the practical and biological features needed for a model octopus that can be cultured repeatedly to address a wide range of fundamental biological questions.

animal behavior and cognition↗

bioRxiv2020

Parallel social information processing circuits are differentially impacted in autism

Parallel processing circuits are thought to dramatically expand the network capabilities of the nervous system. Magnocellular and parvocellular oxytocin neurons have been proposed to subserve two parallel streams of social information processing, which allow a single molecule to encode a diverse array of ethologically distinct behaviors, although to date direct evidence to support this hypothesis is lacking. Here we provide the first comprehensive characterization of magnocellular and parvocellular oxytocin neurons, validated across anatomical, projection target, electrophysiological, and transcriptional criteria. We next used novel multiple feature selection tools in Fmr1 KO mice to provide direct evidence that normal functioning of the parvocellular but not magnocellular oxytocin pathway is required for autism-relevant social reward behavior. Finally, we demonstrate that autism risk genes are uniquely enriched in parvocellular oxytocin neurons. Taken together these results provide the first evidence that oxytocin pathway specific pathogenic mechanisms account for social impairments across a broad range of autism etiologies. One Sentence SummaryPathoclisis of parvocellular oxytocin neurons plays an important role in the pathogenesis of social impairments in autism.

neuroscience↗

bioRxiv2019

Neuronal histone methyltransferase EZH2 regulates neuronal morphogenesis, synaptic plasticity, and cognitive behavior of mice

Recent studies showed that in the nervous system histone methyltransferase EZH2-mediated trimethylation of histone H3 lysine 27 (H3K27me3) acts to regulate neural stem cell proliferation and fate specificity through silencing different gene sets. Here we explored the function of EZH2 in early post-mitotic excitatory neurons by generating a neuronal specific Ezh2 conditional knockout mouse line. The results showed that lack of neuronal EZH2 led to delayed neuronal migration, more complex dendritic arborization, and significantly increased dendritic spine density. RNA-sequencing (RNA-seq) experiments comparing control and Ezh2 knockout neurons revealed that neuronal EZH2 regulated genes related to neuronal morphogenesis. In particular, Pak3 was identified as a target gene suppressed by EZH2 and H3K27me3, and expression of dominant negative PAK3 reversed Ezh2 knockout-induced higher dendritic spine density. Lastly, lack of neuronal EZH2 resulted in impaired memory behaviors in adult mice. Our results demonstrated that neuronal EZH2 played important roles in controlling multiple steps of neuronal morphogenesis during development, which had long-lasting effects on cognitive function in adult mice.

neuroscience↗

bioRxiv2018

SLC6A4 binding site and acute prosocial effects of (+/-)-3,4-methylendioxymethamphetamine (MDMA) are evolutionarily conserved in Octopus bimaculoides.

ABSTRACTHuman and octopus lineages are separated by over 500 million years of evolution, and show divergent anatomical patterns of brain organization. Moreover, while humans exhibit highly complex social behaviors, octopuses are thought to be largely asocial and solitary. Despite these differences, growing evidence suggests that ancient neurotransmitter systems are shared across vertebrate and invertebrate species, and in many cases enable overlapping functions. Here we provide evidence that, as in humans, the atypical amphetamine derivative (+/-)-3,4-methylendioxymethamphetamine (MDMA) enhances acute prosocial behaviors in Octopus bimaculoides. This finding is paralleled by the evolutionary conservation of the serotonin transporter (SERT, encoded by the Slc6A4 gene) binding site of MDMA in the O. bimaculoides genome. Taken together, these data provide evidence that the neural mechanisms subserving social behaviors exist in O. bimaculoides, and indicate that the role of serotonergic neurotransmission in regulating social behaviors is evolutionarily conserved.\n\nONE SENTENCE SUMMARYHere we provide evidence that the atypical amphetamine derivative (+/-)-3,4-methylendioxymethamphetamine (MDMA) increases acute social approach behaviors in Octopus bimaculoides, a finding that is paralleled by the evolutionary conservation of the SLC6A4 binding site of MDMA.

evolutionary biology↗