3,216 research outputs found
Using the maternal immune stimulation model of schizophrenia to investigate the therapeutic efficacy of neuromodulation techniques
The present work used a neurodevelopmental rodent model of schizophrenia, namely the maternal immune stimulation (MIS) model, to study the potency of electrical neuromodulation techniques to ameliorate and even prevent schizophrenia-relevant behavioral and neurobiological abnormalities. Acute and focal deep brain stimulation (DBS) to the medial prefrontal cortex (mPFC) was found to be therapeutically relevant as it successfully normalized deficits in sensorimotor gating and attention selectivity apparent in the adult MIS animals. Using a longitudinal approach the development of sensorimotor gating deficits in the MIS model was traced and was found to exhibit a maturational delay, in accordance with the clinical situation. Further, this approach revealed aberrant neurochemistry profile in the mPFC during the pre-symptomatic period of adolescence, prior to the outbreak of the behavioral deficits. Thus, chronic DBS to the mPFC of adolescent MIS animals was tested and revealed that this approach could prevent the development of deficits in sensorimotor gating, attentional selectivity and reversal learning. Along with these effects, DBS was able to prevent increased lateral ventricles volume and neurochemical alterations as well as the prevention of altered microglia in this model. Finally, a non-invasive neuromodulation technique in the form of transcranial direct current stimulation (tDCS) was chronically applied during adolescence to the prefrontal cortex and revealed that tDCS prevented behavioral deficits belonging to the positive-symptomatology of schizophrenia, along with abnormal lateral ventricles volume. Taken together, this pre-clinical, translational-directed work points to the plausible efficacy of early, non-invasive, neuromodulation approach as a preventive measure for the development of schizophrenia
Near-extremal black holes at late times, backreacted
Black holes display universal behavior near extremality. One such feature is
the late-time blowup of derivatives of linearized perturbations across the
horizon. For generic initial data, this instability is regulated by
backreaction, and the final state is a near-extremal black hole. The aim of
this paper is to study the late time behavior of such black holes analytically
using the weakly broken conformal symmetry of their near-horizon region. In
particular, gravitational backreaction is accounted for within the
Jackiw-Teitelboim model for near-horizon, near-extremal dynamics coupled to
bulk matter.Comment: v2: published versio
The `Second Parameter': A Memory from the Globular Cluster Formation Epoch
We study the correlations between the distribution of stars on the horizontal
branch (HB), the HB morphology, with some other properties of globular clusters
(GCs) in a large sample of GCs. We strengthen previous results that a general
correlation exists only between HB morphology and metallicity. Correlations
with other properties, e.g., central density and core radius, exist only for
GCs within a narrow metallicity range. We conjecture that the lack of
correlations with present properties of GCs (besides metallicity), is because
the variation of the HB morphologies between GCs having similar metallicities
is caused by a process, or processes, whose effect was determined at the
formation time of GCs. This process (or processes) is historically termed the
`second parameter', metallicity being the `first parameter'. We then argue that
the `planet second parameter' model, where the presence of planets and to a
lesser degree brown dwarfs and low mass main sequence stars is the `second
parameter', fits this conjecture.Comment: 11 pages, 4 figures, submitted to MNRA
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