Browsing by Subject "oscillations"

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    Acute d-Amphetamine alters the temporal patterning of intermittent synchronized oscillations in hippocampal and prefrontal circuits of the rat
    (Office of the Vice Chancellor for Research, 2012-04-13) Ahn, S.; Lapish, C.C.; RUBCHINSKY, L.L.
    D-Amphetamine (d-AMPH) increases the bioavailability of numerous catecholamines, including dopamine, throughout the brain and modulates neural firing in cortical and subcortical regions. While a complex array of d-AMPH-mediated effects on firing have been reported, less is known regarding how d-AMPH affects the oscillatory properties of cortical circuits. In the current study, we simultaneously recorded local field potentials from electrode arrays implanted in the medial prefrontal cortex (PFC) and hippocampus (HC) of awake freely moving rats treated with saline, 1.0 mg/kg, or 3.3 mg/kg d-AMPH. The fine temporal structure of synchrony in delta, theta, beta, and gamma bands between these brain regions was examined to characterize how phase synchronization was altered by each dose of d-AMPH relative to saline. Differences were observed in the average level of phase-locking and in the variation of temporal patterns of synchrony on short (sub-second) time scales (including the distribution of durations of desynchronization events. In general, treatment with d-AMPH evoked higher levels of phase-locking. While this imperfect phase-locking can be potentially attained with both large number of short desynchronization episodes and small number of long desynchronization episodes, the data are marked by the dominance of short desynchronization episodes. These results suggest that within the HC and PFC, d-AMPH acts to increase synchronized oscillatory activity. The dominance of short desynchronization episodes suggests that the synchrony can be easily destabilized, yet it can be quickly re-established. The ease with which neural circuits can transition between synchronized and desynchronized dynamics may reflect altered information transfer regimes in these circuits and contribute to the spectrum of effects on cognition frequently observed with d-AMPH.
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    Multiscale activity imaging in mammary gland reveals how oxytocin enables lactation
    (2020) Stevenson, Alexander J.; Vanwalleghem, Gilles; Stewart, Teneale A.; Condon, Nicholas D.; Lloyd-Lewis, Bethan; Marino, Natascia; Putney, James W.; Scott, Ethan K.; Ewing, Adam D.; Davis, Felicity M.; Medicine, School of Medicine
    The mammary epithelium is indispensable for the continued survival of more than 5000 mammalian species. For some, the volume of milk ejected in a single day exceeds their entire blood volume. Here, we unveil the spatiotemporal properties of physiological signals that orchestrate milk ejection. Using quantitative, multidimensional imaging of mammary cell ensembles, we reveal how stimulus evoked Ca2+ oscillations couple to contractions in basal epithelial cells. Moreover, we show that Ca2+-dependent contractions generate the requisite force to physically deform the innermost layer of luminal cells, compelling them to discharge the fluid that they produced and housed. Through the collective action of thousands of these biological positive displacement pumps, each linked to a contractile ductal network, milk is delivered into the mouth of the dependent neonate, seconds after the command.