Morphine modulation of thrombospondin levels in astrocytes and its implications for neurite outgrowth and synapse formation.

Opioid receptor signaling via EGF receptor (EGFR) transactivation and ERK/MAPK phosphorylation initiates diverse cellular responses that are cell type-dependent. In astrocytes, multiple μ opioid receptor-mediated mechanisms of ERK activation exist that are temporally distinctive and feature different outcomes. Upon discovering that chronic opiate treatment of rats down-regulates thrombospondin 1 (TSP1) expression in the nucleus accumbens and cortex, we investigated the mechanism of action of this modulation in astrocytes.

Genetic influences on hippocampal structure and function in recombinant inbred mice.

Previously, we identified separate genetic influences on ventral versus dorsal hippocampal volume in BXD recombinant inbred mice [Martin MV, Dong HX, Vallera D, Lu L, Williams RW, Rosen GD, et al. Independent quantitative trait loci influence ventral and dorsal hippocampal volume in recombinant inbred strains of mice. Genes Brain Behav 2006;5:614-23].

Profiling signaling peptides in single mammalian cells using mass spectrometry.

The peptide content of individual mammalian cells is profiled using matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. Both enzymatic and nonenzymatic procedures, including a glycerol cell stabilization method, are reported for the isolation of individual mammalian cells in a manner compatible with MALDI MS measurements. Guided microdeposition of MALDI matrix allows samples to be created with suitable analyte-to-matrix ratios.

The influence of post-nerve injury survival duration on receptive field size: location, location, location.

In the present study, we examined the relationship between post-injury survival duration and receptive field size at multiple levels of the ascending somatosensory neuroaxis. In experimentally naïve subjects, receptive fields on the glabrous hand are typically restricted to single digits. Yet, following targeted nerve section, receptive fields often span multiple digits.

Morphological correlates of injury-induced reorganization in primate somatosensory cortex.

Background: Topographic reorganization of central maps following peripheral nerve injury has been well characterized. Despite extensive documentation of these physiological changes, the underlying anatomical correlates have yet to be fully explored. In this study, we used Golgi impregnation and light microscopy to assess dendritic morphology following denervation of the glabrous hand surface in adult primates.

Some antiepileptic compounds impair learning by rats in a Morris water maze.

In the present experiments, we investigated the effects of several commonly employed antiepileptic drugs on the performance of adult rats in a Morris water maze task. We found that phenytoin treatment produced the most deleterious performance impairments across all days of training, and that these performance deficits are not likely due to any general sensorimotor impairments. Carbamazepine had milder, but detectable negative effects, as carbamazepine-treated animals exhibited initial acquisition deficits, but rapidly achieved escape levels comparable to controls.

Is procedural memory relatively spared from age effects?

Numerous types of age-related deficits in the nervous system have been well documented. While a distinction between general types of memories that are susceptible to compromise with advanced age has been fairly well agreed upon, it is often difficult to determine exactly which specific processes are detrimentally influenced. In this study, we used a paradigm that enabled us to distinguish between effects associated with gross motor deficits and those due to learning and memory of a motor skill, per se.

Experience effects on brain development: possible contributions to psychopathology.

Researchers and clinicians are increasingly recognizing that psychological and psychiatric disorders are often developmentally progressive, and that diagnosis often represents a point along that progression that is defined largely by our abilities to detect symptoms. As a result, strategies that guide our searches for the root causes and etiologies of these disorders are beginning to change. This review describes interactions between genetics and experience that influence the development of psychopathologies.

The nootropic properties of ginseng saponin Rb1 are linked to effects on anxiety.

Previous studies have shown that crude ginseng extracts enhance performance on shock-motivated tasks. Whether such performance enhancements are due to memory-enhancing (nootropic) properties of ginseng, or to other non-specific effects such as an influence on anxiety has not been determined. In the present study, we evaluated both the nootropic and anxiolytic effects of the ginseng saponin Rb1.

A brain adaptation view of plasticity: is synaptic plasticity an overly limited concept?

A view that is emerging is that the brain has multiple forms of plasticity that must be governed, at least in part, by independent mechanisms. This view is illustrated by: (1) the apparent separate governance of some non-neural changes by activity, in contrast to synaptic changes driven by learning; (2) the apparent independence of different kinds of synaptic changes that occur in response to the learning aspects of training; (3) the occurrence of separate patterns of synaptic plasticity in the same system in response to different task demands; and (4) apparent dissociations between behaviorally induced synaptogenesis and LTP. The historical focus of research and theory in areas ranging from learning and memory to experiential modulation of brain development has been heavily upon synaptic plasticity since shortly after the discovery of the synapse.

Exercise, experience and the aging brain.

While limited research is available, evidence indicates that physical and mental activity influence the aging process. Human data show that executive functions of the type associated with frontal lobe and hippocampal regions of the brain may be selectively maintained or enhanced in humans with higher levels of fitness. Similarly enhanced performance is observed in aged animals exposed to elevated physical and mental demand and it appears that the vascular component of the brain response may be driven by physical activity whereas the neuronal component may reflect learning.

Effects of Fragile X syndrome and an FMR1 knockout mouse model on forebrain neuronal cell biology.

The neurological deficits exhibited by patients with Fragile X syndrome (FraX) have been attributed to the absence of the Fragile X Mental Retardation Protein (FMRP), the product of the FMR1 gene, which is nonfunctional in these individuals. While a great deal has been learned about FraX using non-invasive techniques and autopsy tissue from humans, the limited availability of subjects and specimens severely restricts the rate at which such data can be collected and the types of experimental questions posed. In view of these limitations, a transgenic mouse model of FraX has been constructed in which the FMR1 gene is selectively knocked out (KO) [Bakker et al.

A converging-methods approach to fragile X syndrome.

Converging approaches across domains of brain anatomy, cell biology, and behavior indicate that Fragile X syndrome, arising from impaired expression of a single gene and protein, appears to involve an aberration of normal developmental processes. Synapse overproduction and selective elimination, or pruning, characterize normal brain development. In autopsy tissue from Fragile X patients and in a knockout mouse model of the disease, synapse overproduction appears to occur unaccompanied by synapse pruning and maturation, leaving an excess of immature spine synapses in place.