ABSTRACT: A novel analytical brain block tool to enable functional annotation of discriminatory transcript biomarkers among discrete regions of the fronto-limbic circuit in primate brain
Project description:We describe a novel method for obtaining discrete regions from the fronto-limbic circuits of a 4 year old and a 5 year old, male, intact, frozen non-human primate (NHP) brain, from which we use transcriptional profiling and a new algorithm to identify region-exclusive RNA signatures for Area 25 (NFκB and dopamine receptor signaling), the anterior cingulate cortex (LXR/RXR signaling), the amygdala (semaphorin signaling), and the hippocampus (Caþþ and retinoic acid signaling). Profiling of 4 discrete brain regions in 2 individual non-human primate subjects.
Project description:We describe a novel method for obtaining discrete regions from the fronto-limbic circuits of a 4 year old and a 5 year old, male, intact, frozen non-human primate (NHP) brain, from which we use transcriptional profiling and a new algorithm to identify region-exclusive RNA signatures for Area 25 (NFκB and dopamine receptor signaling), the anterior cingulate cortex (LXR/RXR signaling), the amygdala (semaphorin signaling), and the hippocampus (Caþþ and retinoic acid signaling).
Project description:At the core of addiction, drug experiences induce circuit-specific transcriptional adaptations to hijack the native mechanisms of neuroplasticity and promote maladaptive behaviors. In the present study, we utilized 3’-RNA-sequencing to define the transcriptional landscapes of five brain nuclei within the reward circuit following distinct cocaine experiences. We exposed mice to cocaine (20 mg/kg, IP), acutely (single exposure), repeatedly (5 daily exposures) as well as to a challenge cocaine (acute exposure after 21 days of abstinence following repeated cocaine). We then profiled transcription (applying 3’-RNAseq) within key brain structures of the reward circuitry: limbic cortex- medial prefrontal and cingulate together (LCtx), nucleus accumbens (NAc), dorsal striatum (DS), amygdala (Amy), and lateral hypothalamus (LH) at 0, 1, 2, 4 hrs following cocaine exposure.
Project description:Individual differences in human temperament can increase the risk of psychiatric disorders like depression and anxiety. Our laboratory utilized a rat model of temperamental differences to assess neurodevelopmental factors underlying emotional behavior differences. Rats selectively bred for low novelty exploration (Low Responders, LR) display high levels of anxiety- and depression-like behavior compared to High Novelty Responder (HR) rats. Using transcriptome profiling, the present study uncovered vast gene expression differences in the early postnatal HR versus LR limbic brain, including changes in genes involved in cellular metabolism. These data led us to hypothesize that rats prone to high (versus low) anxiety/depression-like behavior exhibit distinct patterns of brain metabolism during the first weeks of life, which may reflect disparate patterns of synaptogenesis and brain circuit development. All samples were generated from Sprague-Dawley male rats selectively bred for high novelty response (HRs) or low novelty response (LRs).
Project description:Circuit formation in the central nervous system has been historically studied during development, after which cell-autonomous and nonautonomous wiring factors inactivate. In principle, balanced reactivation of such factors could enable further wiring in adults, but their relative contributions may be circuit dependent and are largely unknown. Here, we investigated hippocampal mossy fiber sprouting to gain insight into wiring mechanisms in mature circuits. We found that sole ectopic expression of Id2 in granule cells is capable of driving mossy fiber sprouting in healthy adult mouse and rat. Mice with the new mossy fiber circuit solved spatial problems equally well as controls but appeared to rely on local rather than global spatial cues. Our results demonstrate reprogrammed connectivity in mature neurons by one defined factor and an assembly of a new synaptic circuit in adult brain.
Project description:This SuperSeries is composed of the following subset Series: GSE22521: Gene expression in primate postnatal brain through lifespan - prefrontal cortex GSE22569: Gene expression in primate postnatal brain through lifespan - cerebellar cortex Refer to individual Series
Project description:Domoic acid (DA), a potent glutamate agonist, is produced by marine algae and can bioconcentrate in finfish and shellfish. Current regulatory limits constrain environmental exposures to this toxin to 20 ppm in shellfish tissue (~0.075-0.1 mg/kg), but changing environmental conditions are leading to more frequent and longer lasting DA algal blooms. Further, recent studies suggest that chronic DA exposure, at levels below this limit, is associated with deficits in memory in adults. To understand how low-level, chronic exposure to this toxin impacts the limbic system of the brain, the present study used magnetic resonance imaging (MRI) and histopathology to assess changes in the hippocampus, thalamus, fornix, fimbria, and internal capsule in a nonhuman primate model. Twenty-eight adult, female Macaca fascicularis were orally exposed to 0.075 and 0.15 mg/kg/day for up to two years. A subset of these females (n=12) underwent a single, sedated MRI scan in vivo, to assess volumetric and tractography changes in the hippocampus, thalamus, and connecting white matter tracts, and all animals were necropsied to evaluate the cellularity and morphology of the neurons, astrocytes, and microglia in these regions. MRI and histopathology evaluations did not suggest signs of overt neuropathology, but revealed that some animals, especially in the 0.15 mg/kg/day DA exposure group, expressed focal microglia reactions within both white and gray matter structures of the limbic system. These results suggest that chronic exposure to levels of DA near the human regulatory limit does not lead to acute neuropathic effects but may induce microglial responses and promote neuroinflammatory pathways in a nonhuman primate model of contemporary human exposure to DA.
Project description:Although continual expansion of the brain during primate evolution accounts for our enhanced cognitive capabilities, the drivers of brain evolution have scarcely been explored. Tree shrews are closely related to primates that comparing their brains to primate brains at the single-cell level will provide new insights into the evolution of the primate brain.
