Publications by authors named "R J Clem"

Article Synopsis
  • Contextual memories are important for survival but need to fade when they're no longer useful; extinction creates a competing memory.
  • Recent research shows that specific interneurons (SST-INs) in the ventral hippocampus are activated during the extinction of fear-based memories.
  • Manipulating these SST-INs affects behavior related to freezing responses, indicating their crucial role in memory extinction across different types of conditioning, not just related to fear.
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Oral infection of mosquitoes by arboviruses often results in a large degree of variation in the amount of infectious virus between individual mosquitoes, even when the mosquitoes are from inbred laboratory strains. This variability in arbovirus load has been shown to affect virus transmissibility. Previously, our group described population genetic and specific infectivity differences between the virus populations found in high and low titer mosquitoes that had been orally infected with Sindbis virus (SINV).

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Basolateral amygdala (BLA) is a key hub for affect in the brain, and dysfunction within this area contributes to a host of psychiatric disorders. BLA is extensively and reciprocally interconnected with frontal cortex, and some aspects of its function are evolutionarily conserved across rodents, anthropoid primates, and humans. Neuron density in BLA is substantially lower in primates compared to murine rodents, and frontal cortex (FC) is dramatically expanded in primates, particularly the more anterior granular and dysgranular areas.

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The rodent medial prefrontal cortex (mPFC) is functionally organized across the dorsoventral axis, where dorsal and ventral subregions promote and suppress fear, respectively. As the ventral-most subregion, the dorsal peduncular cortex (DP) is hypothesized to function in fear suppression. However, this role has not been explicitly tested.

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Variability in how individuals respond to pathogens is a hallmark of infectious disease, yet the basis for individual variation in host response is often poorly understood. The titer of infectious virus among individual mosquitoes infected with arboviruses is frequently observed to vary by several orders of magnitude in a single experiment, even when the mosquitoes are highly inbred. To better understand the basis for this titer variation, we sequenced populations of Sindbis virus (SINV) obtained from individual infected Aedes aegypti mosquitoes that, despite being from a highly inbred laboratory colony, differed in their titers of infectious virus by approximately 10,000-fold.

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