Cognitive consequences of sleep deprivation, shiftwork, and heat exposure for underground miners.

Sleep deprivation, abnormal sleep patterns arising from working rotating shifts, and exposure to high ambient temperatures contribute to physical and cognitive dysfunction. We examined the effects of these on 19 (41.5 ± 5.

Identification of a rapid eye movement sleep window for learning of the win-shift radial arm maze task for male Sprague-Dawley rats.

This study identified a rapid eye movement sleep window (RSW) for the eight-arm win-shift radial arm maze (RAM) task. The RSW is defined as a period of time after training during which rapid eye movement (REM) sleep is necessary for efficient learning of a task. Rats were trained over a 15-day period on the win-shift RAM task.

Minimal impact of inadvertent sleep between naps on the MSLT and MWT.

Sleepiness is often neurophysiologically assessed using the multiple sleep latency test (MSLT) or the maintenance of wakefulness test (MWT). We examined the frequency of incidental intersession napping during MSLT and MWT testing to see if there was a relationship between intersession napping, mean sleep latency and subjective sleepiness on the Epworth Sleepiness Scale (ESS). We conducted a retrospective analysis of 24 studies of subjects who underwent either a MSLT or a MWT as a component of their clinical assessment and had coincidental wireless telemetry recording of their sleep in between scheduled naps.

Post-training intra-striatal scopolamine or flupenthixol impairs radial maze learning in rats.

Systemic treatments with acetylcholine (ACh) or dopamine (DA) receptor antagonists during hours 0-4 but not during hours 5-8 following training on a radial arm maze (RAM) or lesions of the dorsal striata impair learning. This suggested that intra-striatal infusions of ACh or DA receptor antagonists during hours 0-4 following training may impair learning. Rats were randomly assigned to groups (ns=5-11) receiving dorsal striatal infusions of the ACh receptor antagonist scopolamine (0-18 microg/microL at 0 and 2h or at 4 and 6h after training), the DA receptor antagonist cis-flupenthixol (0-25 microg/microL at 0, 4 or 12h after training) or the inactive isomer trans-flupenthixol (6 microg/microL at 0 h after training).

Scopolamine during the paradoxical sleep window impairs radial arm maze learning in rats.

It has been proposed that there are paradoxical sleep windows (PSW) during which REM sleep is required for effective learning. Thus, rats deprived of REM sleep during 0-4 (but not 5-8) h after training show impaired learning of a radial maze task. As cholinergic (ACh) systems are active during REM sleep and may be involved in learning, this experiment investigated the effects on learning of pharmacological manipulation of the cholinergic system during the period identified as the PSW.

Study of the neurotransmitter dopamine and the neurotoxin 6-hydroxydopamine by electrospray ionization coupled with tandem mass spectrometry.

Electrospray ionization combined with tandem mass spectrometry has been applied to a study of dopamine and 6-hydroxydopamine, an important neurotransmitter and a well-known neurotoxin, respectively. Both protonated and deprotonated molecules were observed for the two compounds. Upon collision-induced dissociation of protonated and deprotonated 6-hydroxydopamine molecules, the number of fragmentation pathways observed was greater than that observed with protonated and deprotonated dopamine molecules; the greater proclivity to fragment of the former is due to the 6-substituted hydroxyl group, which is para to the 3-OH group and ortho to the CH2CH2NH2 group.