A neuronal signature for monogamous reunion, bioRxiv, 2019-06-19
AbstractPair bond formation depends vitally on neuromodulatory signaling within the nucleus accumbens, but the neuronal dynamics underlying this behavior remain unclear. Using in vivo Ca2+ imaging in monogamous prairie voles, we found that pair bonding does not elicit differences in overall nucleus accumbens Ca2+ activity. Instead, we identified distinct neuronal ensembles in this region recruited during approach to either a partner or novel vole. The partner-approach neuronal ensemble increased in size following bond formation, representing a substrate linked to bond formation and maturation.
biorxiv neuroscience 100-200-users 2019Immune, Autonomic, and Endocrine Dysregulation in Autism and Ehlers-Danlos SyndromeHypermobility Spectrum Disorders Versus Unaffected Controls, bioRxiv, 2019-06-14
ABSTRACTBackgroundA growing body of literature suggests etiological overlap between Ehlers-Danlos syndrome (EDS)hypermobility spectrum disorders (HSD) and some cases of autism, although this relationship is poorly delineated. In addition, immune, autonomic, and endocrine dysregulation are reported in both conditions and may be relevant to their respective etiologies.AimsTo study symptom overlap in these two comorbid spectrum conditions.Methods and ProceduresWe surveyed 702 adults aged 25+ years on a variety of EDSHSD-related health topics, comparing individuals with EDSHSD, autism, and unaffected controls.Outcomes and ResultsThe autism group reported similar though less severe symptomology as the EDSHSD group, especially in areas of immuneautonomicendocrine dysregulation, connective tissue abnormalities (i.e., skin, bruisingbleeding), and chronic pain. EDSHSD mothers with autistic children reported more immune symptoms than EDSHSD mothers without, suggesting the maternal immune system could play a heritable role in these conditions (p = 0.0119).Conclusions and ImplicationsThese data suggest that EDSHSD and autism share aspects of immuneautonomicendocrine dysregulation, pain, and some tissue fragility, which is typically more severe in the former. This overlap, as well as documented comorbidity, suggests some forms of autism may be hereditary connective tissue disorders (HCTD).
biorxiv neuroscience 100-200-users 2019Two distinct feedback codes in V1 for ‘real’ and ‘imaginary’ internal experiences, bioRxiv, 2019-06-14
AbstractVisual illusions and visual imagery are conscious sensory events that lack a corresponding physical input. But while everyday mental imagery feels distinct from incoming stimulus input, visual illusions, like hallucinations, are under limited volitional control and appear indistinguishable from physical reality. Illusions are thought to arise from lower-level processes within sensory cortices. In contrast, imagery involves a wide network of brain areas that recruit early visual cortices for the sensory representation of the imagined stimulus. Here, we combine laminar fMRI brain imaging with psychophysical methods and multivariate pattern analysis to investigate in human participants how seemingly ‘real’ and imaginary non-physical experiences are processed in primary visual cortex (V1). We find that the content of mental imagery is only decodable in deep layers, whereas illusory content is only decodable at superficial depths. This suggests that feedback to the different layers may serve distinct functions low-level feedback to superficial layers might be responsible for shaping perception-like experiences, while deep-layer feedback might serve the formation of a more malleable ‘inner’ world, separate from ongoing perception.
biorxiv neuroscience 0-100-users 2019Independent population coding of the present and the past in prefrontal cortex during learning, bioRxiv, 2019-06-13
AbstractMedial prefrontal cortex (mPfC) plays a role in both immediate behaviour and short-term memory. Unknown is whether the present and past are represented simultaneously or separately in mPfC populations. To address this, we analysed mPfC population activity of rats learning rules in a Y-maze, with self-initiated choice trials followed by a self-paced return during the inter-trial interval. Joint mPfC population activity encoded solely present events and actions during the trial, with decoding of the past at chance; conversely, population encoding of the same features in the immediately following inter-trial interval was solely of the past. Despite being contiguous in time, each population orthogonally encoded the present and past of the same events and actions. Consequently, only the population code of the present during the trials, and not the past coding of the inter-trials intervals, was re-activated in subsequent sleep. Our results suggest that representations of the past and present in the mPfC independently contribute to the learning of a new rule.
biorxiv neuroscience 0-100-users 2019Brain-wide mapping of contextual fear memory engram ensembles supports the dispersed engram complex hypothesis, bioRxiv, 2019-06-12
Neuronal ensembles that hold specific memory (memory engrams) have been identified in the hippocampus, amygdala, and cortex. It has been hypothesized that engrams for a specific memory are distributed among multiple brain regions that are functionally connected. Here, we report the hitherto most extensive engram map for contextual fear memory by characterizing activity-tagged neurons in 409 regions using SHIELD-based tissue phenotyping. The mapping was aided by a novel engram index, which identified cFos+ brain regions holding engrams with a high probability. Optogenetic manipulations confirmed previously known engrams and revealed new engrams. Many of these engram holding-regions were functionally connected to the CA1 or amygdala engrams. Simultaneous chemogenetic reactivation of multiple engrams, which mimics natural memory recall, conferred a greater level of memory recall than reactivation of a single engram ensemble. Overall, our study supports the hypothesis that a memory is stored in functionally connected engrams distributed across multiple brain regions.
biorxiv neuroscience 100-200-users 20197 Tesla MRI of the ex vivo human brain at 100 micron resolution, bioRxiv, 2019-05-31
AbstractWe present an ultra-high resolution MRI dataset of an ex vivo human brain specimen. The brain specimen was donated by a 58-year-old woman who had no history of neurological disease and died of non-neurological causes. After fixation in 10% formalin, the specimen was imaged on a 7 Tesla MRI scanner at 100 μm isotropic resolution using a custom-built 31-channel receive array coil. Single-echo multi-flip Fast Low-Angle SHot (FLASH) data were acquired over 100 hours of scan time (25 hours per flip angle), allowing derivation of a T1 parameter map and synthesized FLASH volumes. This dataset provides an unprecedented view of the three-dimensional neuroanatomy of the human brain. To optimize the utility of this resource, we warped the dataset into standard stereotactic space. We now distribute the dataset in both native space and stereotactic space to the academic community via multiple platforms. We envision that this dataset will have a broad range of investigational, educational, and clinical applications that will advance understanding of human brain anatomy in health and disease.<jatstable-wrap id=utbl1 orientation=portrait position=float><jatsgraphic xmlnsxlink=httpwww.w3.org1999xlink xlinkhref=649822v2_utbl1 position=float orientation=portrait ><jatstable-wrap>
biorxiv neuroscience 500+-users 2019