Jose Julio Rodriguez

The University of Manchester, Manchester, England, United Kingdom

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Publications (3)12.57 Total impact

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    ABSTRACT: Author Summary The birth of adult hippocampal neurons is associated with enhanced learning and memory performance. In particular, spatial learning increases the survival and the proliferation of newborn cells, but surprisingly, it also decreases their number. Here, we hypothesized that spatial learning also depends upon the death of newborn hippocampal neurons. We examined the effect of spatial learning in the water maze on cell birth and death in the rodent hippocampus. We then determined the influence of an inhibitor of cell death on memory abilities and learning-induced changes in cell death, cell proliferation, and cell survival. We show that learning increases the elimination of the youngest newborn cells during a specific developmental period. The cell-death inhibitor impairs memory abilities and blocks the learning-induced cell death, the survival-promoting effect of learning on older newly born neurons, and the subsequent learning-induced proliferation of neural precursors. These results show that spatial learning induces cell death in the hippocampus, a phenomenon that subserves learning and is necessary for both the survival of older newly born neurons and the proliferation of neural precursors. These findings suggest that during learning, neuronal networks are sculpted by a tightly regulated selection of newly born neurons and reveal a novel mechanism mediating learning and memory in the adult brain.
    PLoS Biology 09/2007; 5(8):e214. DOI:10.1371/journal.pbio.0050214 · 9.34 Impact Factor
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    ABSTRACT: The role of the monoamine serotonin (5-HT) in modulating the neural networks underlying axial locomotor movements was studied in an adult amphibian urodele, Pleurodeles waltl. 5-HT was applied to an in vitro brainstem–spinal cord preparation of P. waltl, which displayed fictive axial locomotor patterns following bath application of N-methyl-D-aspartate (5 μM) with D-serine (10 μM). Our results showed that 5-HT (1–25 μM) produces a reversible increase in the cycle duration and the duration of rhythmic bursting activity recorded extracellularly from ventral roots innervating the axial musculature. When applied alone, 5-HT does not trigger axial locomotor activity. The distribution pattern of 5-HT immunoreactive (5-HT-ir) cells along the spinal cord was investigated both in intact and in chronic spinal animals. The number of 5-HT-ir cell bodies is higher at brachial levels and decreases through crural levels. Sparse oval or fusiform 5-HT-ir somata are present within the gray matter, just ventrolateral to the central canal. Longitudinal fibers were detected throughout the entire white matter, except in the medial part of the dorsal funiculi. Two columns of intensely labeled and profusely branching thick and thin fibers associated with numerous varicosities run continuously along the ventrolateral surface of the spinal cord. Three weeks following full spinal cord transection at the level of the second spinal root, all longitudinal processes had disappeared, indicating their supraspinal origin, whereas the ventrolateral plexes remained, suggesting that they originated from intraspinal 5-HT-ir cell bodies. Our data showing that spinal 5-HT is organized according to a rostrocaudal gradient suggest that the 5-HT systems of P. waltl are not related to the presence of limb motor pools but more likely are related to axial central pattern generators (CPGs) networks down the length of the spinal cord. The possible involvement of these two sources (descending vs. intraspinal) of 5-HT innervation in the modulation of the axial CPGs is discussed. J. Comp. Neurol. 419:49–60, 2000. © 2000 Wiley-Liss, Inc.
    The Journal of Comparative Neurology 03/2000; 419(1):49 - 60. DOI:10.1002/(SICI)1096-9861(20000327)419:1<49::AID-CNE3>3.0.CO;2-# · 3.23 Impact Factor