Hippocampus-dependent emergence of spatial sequence coding in retrosplenial cortex.

Retrosplenial cortex (RSC) is involved in visuospatial integration and spatial learning, and RSC neurons exhibit discrete, place cell-like sequential activity that resembles the population code of space in hippocampus. To investigate the origins and population dynamics of this activity, we combined longitudinal cellular calcium imaging of dysgranular RSC neurons in mice with excitotoxic hippocampal lesions. We tracked the emergence and stability of RSC spatial activity over consecutive imaging sessions. Overall, spatial activity in RSC was experience-dependent, emerging gradually over time, but, as seen in the hippocampus, the spatial code changed dynamically across days. Bilateral but not unilateral hippocampal lesions impeded the development of spatial activity in RSC. Thus, the emergence of spatial activity in RSC, a major recipient of hippocampal information, depends critically on an intact hippocampus; the indirect connections between the dysgranular RSC and the hippocampus further indicate that hippocampus may exert such influences polysynaptically within neocortex

Expression patterns of Slit and Robo family members in adult mouse spinal cord and peripheral nervous system.

The secreted glycoproteins, Slit1-3, are classic axon guidance molecules that act as repulsive cues through their well characterised receptors Robo1-2 to allow precise axon pathfinding and neuronal migration. The expression patterns of Slit1-3 and Robo1-2 have been most characterized in the rodent developing nervous system and the adult brain, but little is known about their expression patterns in the adult rodent peripheral nervous system. Here, we report a detailed expression analysis of Slit1-3 and Robo1-2 in the adult mouse sciatic nerve as well as their expression in the nerve cell bodies within the ventral spinal cord (motor neurons) and dorsal root ganglion (sensory neurons). Our results show that, in the adult mouse peripheral nervous system, Slit1-3 and Robo1-2 are expressed in the cell bodies and axons of both motor and sensory neurons. While Slit1 and Robo2 are only expressed in peripheral axons and their cell bodies, Slit2, Slit3 and Robo1 are also expressed in satellite cells of the dorsal root ganglion, Schwann cells and fibroblasts of peripheral nerves. In addition to these expression patterns, we also demonstrate the expression of Robo1 in blood vessels of the peripheral nerves. Our work gives important new data on the expression patterns of Slit and Robo family members within the peripheral nervous system that may relate both to nerve homeostasis and the reaction of the peripheral nerves to injury

Nicotinic Acid Adenine Dinucleotide Phosphate Potentiates Neurite Outgrowth

Ca2+ regulates a spectrum of cellular processes including many aspects of neuronal function. Ca2+-sensitive events such as neurite extension and axonal guidance are driven by Ca2+ signals that are precisely organized in both time and space. These complex cues result from both Ca2+ influx across the plasma membrane and the mobilization of intracellular Ca2+ stores. In the present study, using rat cortical neurons, we have examined the effects of the novel intracellular Ca 2+-mobilizing messenger nicotinic acid adenine dinucleotide phosphate (NAADP) on neurite length and cytosolic Ca2+ levels. We show that NAADP potentiates neurite extension in response to serum and nerve growth factor and stimulates increases in cytosolic Ca2+ from bafilomycin- sensitive Ca2+ stores. Simultaneous blockade of inositol trisphosphate and ryanodine receptors abolished the effects of NAADP on neurite length and reduced the magnitude of NAADP-mediated Ca2+ signals. This is the first report demonstrating functional NAADP receptors in a mammalian neuron. Interplay between NAADP receptors and more established intracellular Ca2+ channels may therefore play important signaling roles in the nervous system

Soru

Ġabra ta’ poeżiji u proża li tinkludi: Min jixtieq id-deni ‘l ġaru jiġih f’daru ta’ L. C. – Qalbieni! ta’ Dun Karm – Il-gideb għomru qasir ta’ T. Z. – Frak – Għasel Malti – Malta ġawhra tal-Mediterran ta’ D. K. – Soru ta’ D. K.N/

The undervalued potential of positional therapy in position-dependent snoring and obstructive sleep apnea—a review of the literature

PURPOSE: Research during the past 10–20 years shows that positional therapy (PT) has a significant influence on the apnea–hypopnea index. These studies are predominantly performed as case series on a comparably small number of patients. Still, results have not found their way into the daily diagnostic and treatment routine. An average of 56 % of patients with obstructive sleep apnea (OSA) have position-dependent OSA (POSA), commonly defined as a difference of 50 % or more in apnea index between supine and non-supine positions. A great deal could be gained in treating patients with POSA with PT. The aim of this paper was to perform a thorough review of the literature on positional sleep apnea and its therapy. METHODS: A broad search strategy was run electronically in the MEDLINE and EMBASE databases using synonyms for position and sleep apnea. RESULTS: Sixteen studies were found which examined the effect of PT on OSA. In this literature review, we discuss the various techniques, results, and compliance rates. CONCLUSION: Long-term compliance for PT remains an issue, and although remarkable results have been shown using innovative treatment concepts for PT, there is room for both technical improvement of the devices and for further research