Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I

The concept of memory consolidation generally refers to processes which, after some period of time and in the absence of further training, make memories stable to interference from competing or degrading factors There is as yet no single accepted view regarding which concrete processes underlie memory consolidation. It remains unclear which mechanisms support the effects of sleep on memory. There are two main theories explaining the effects of sleep on different memory systems. According to the first 700 Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 61, No. 2, pp. 161-169, March-April, 2011. Original article submitted December 23, 2009. Accepted March 3, 2010. The effects of daytime sleep consisting exclusively of non-REM (NREM) sleep on the consolidation of declarative memory and overall functional status were studied in humans. In addition, the effects of daytime sleep on memory were studied in relation to the level of fixation of assimilated information. At the beginning of each experiment, the subject was given a declarative memory task: to remember 60 semantically unrelated pairs of words, 30 of which were memorized once and 30 twice; at the end of the experiment, the level of memory fixation was assessed. Each subject took part in two experiments: a test protocol, in which training was followed by sleep, and a control protocol, in which a video was watched instead of sleeping. The results showed that daytime sleep facilitated the reproduction of declarative memory, with improvements in the remembering of the 30 pairs of words memorized once but not in remembering the 30 pairs of words memorized twice. The dynamics of a simple sensorimotor reaction and subjective assessments of wellbeing, activity, and mood with and without sleep were similar, and there were no significant differences between the two types of experiment

Crystal structure and thermodynamic stability of the [Hg(Pyridine)\u2084(NO\u2083)\u2082] \ub7 2(Pyridine) inclusion compound

The studied compound belongs to the family of [MPy\u2084X\u2082] c5 2Py isomorphous clathrates. Its crystal structure exhibits a van der Waals architecture formed by neutral [HgPy\u2084(NO\u2083)\u2082] host molecules, with the guest pyridine molecules included in the cavities of the host lattice. The host complex is formed by coordination of four pyridines, located near the equatorial plane, and two nitrates, located axially, to the Hg(II) cation. One of nitrates ligates as a monodentate ligand and another as a bidentate. The coordination polyhedron is 'HgN\u2084O\u2083', with average Hg-NPy and Hg-Onitrate distances of 2.38(5) and 2.68(1) \uc5, respectively. The crystal structure is complicated with a superlattice and the crystal symmetry reduced to monoclinic, as compared to the structure usually occurring in the [MPy\u2084X\u2082] c5 2Py clathrates. The pyridine vapor pressure over the clathrate was measured in the 293-369 K temperature range by the static tensimetric method. Thermodynamic parameters of the clathrate dissociation were calculated from these data. For the reaction 1/3[HgPy\u2084(NO\u2083)\u2082] c5 2Pysolid=1/3[HgPy\u2083(NO\u2083)\u2082] solid + Pygas the parameters are as follows: \u394H\ubaav = 49.4(2) kJ/mol, \u394S\ubaav = 127(2) J/(mol K) and \u394G\uba\u2082\u2089\u2088=11.4(3) kJ/mol. The results are compared with previously reported data on compounds of the [MPy\u2084(NO\u2083)\u2082] c5 2Py series.NRC publication: Ye

Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I

There is a strongly held opinion that one of the most important functions of sleep is its involvement in the formation of memories The standard test for studies of learning and memory processes in animals is the Morris water test Effects of Sleep Deprivation on Consolidation of Spatial Memory in Rats after 1032 Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 61, No. 3, pp. 322-331, May-June, 2011. Original article submitted December 24, 2009. Accepted October 18, 2010. The effects of sleep deprivation produced using a carousel method on the consolidation of spatial memory were studied in rats (male Wistar rats) after one-day training using the Frick et al. protocol (2000) in a Morris water maze. Data were obtained providing evidence that the memory trace after rapid 3-h training was retained for one day. Sleep deprivation for 24 h after training prevented reinforcement (consolidation) of spatial memory. The results led to the conclusion that a model based on one-day training can be used to study the neurophysiological and neurochemical mechanisms of the effects of sleep deprivation on consolidation of spatial memory