Sleep deprivation and brain acetylcholine

Rats deprived of D-state sleep (and, to some extent, of slow-wave sleep) for 96 hours show a significant fall in brain acetylcholine in the telencephalon; there were no significant changes in the diencephalon and brain stem. Restraint stress and activity wheel stress produced no significant change in acetylcholine levels in any of these regions; the telencephalic response to sleep deprivation, therefore, cannot be attributed to nonspecific stress. The effects of D-state deprivation and the psychoactive anticholinergic drugs on telencephalic acetylcholine levels are similar.     

Sleep after exercise

After moderate treadmill exercise, marked decreases in operant responding and in latency to onset of behavioral sleep occurs in cats. The sleep produced is characterized by enhancement of synchronized electroencephalographic activity with suppression of the desynchronized phase. The result is consistent with the theory that a function of synchronized sleep is to facilitate recovery from fatigue.     

Schemas and memory consolidation

Memory encoding occurs rapidly, but the consolidation of memory in the neocortex has long been held to be a more gradual process. We now report, however, that systems consolidation can occur extremely quickly if an associative "schema" into which new information is incorporated has previously been created. In experiments using a hippocampal-dependent paired-associate task for rats, the memory of flavor-place associations became persistent over time as a putative neocortical schema gradually developed. New traces, trained for only one trial, then became assimilated and rapidly hippocampal-independent. Schemas also played a causal role in the creation of lasting associative memory representations during one-trial learning. The concept of neocortical schemas may unite psychological accounts of knowledge structures with neurobiological theories of systems memory consolidation.     

Sleep deprivation in the rat

Sleep deprivation, induced by injections of dextroamphetamine or by forced treadmill activity, resulted in a temporary increase in daily sleep time. However, increasing the period of sleep deprivation above 24 hours to 72 or 120 hours did not result in increased recovery sleep above that present in the 24-hour group.     

Sleep stage characteristics of long and short sleepers

The possibility of different sleep stage characteristics being associated with different sleep lengths was explored by comparing two groups of high school seniors, who characteristically slept 6(1/2) hours or less or who slept 8(1/2) hours or more, with an age-matched control group not selected on the basis of sleep length. All-night electroencephalography was used to examine the sleep stage characteristics of these groups. Compared with the unselected age-matched group, the short sleepers showed no significant diminution in their stage 4 (deep) or rapid eye movement (dream) sleep. The long sleepers were observed to obtain significantly more rapid eye movement sleep than did the other groups.     

Maternal-fetal interaction and immunological memory

Female rats of the poorly responding, inbred F344 strain were immunized with poly(Glu(52)Lys(33)Tyr(15)) aggregated with methylated bovine serum albumin, and then they were mated. The first and second litters in the F(1) generation and in the F(2) generation showed an enhanced immune response. When poly-lysine was used as the aggregating agent, enhancement occurred in only the first litter of the F(1) generation and in the F(2) generation. In both cases, antigen was transmitted from the immunized female to her offspring, where it localized in the bone marrow and, in a few cases, in the thymus and spleen also. The transplacental passage of antigen is probably the basis for the enhanced antibody response, which is a manifestation of immunological memory.     

Microfluidic memory and control devices

We demonstrate microscopic fluidic control and memory elements through the use of an aqueous viscoelastic polymer solution as a working fluid. By exploiting the fluid's non-Newtonian rheological properties, we were able to demonstrate both a flux stabilizer and a bistable flip-flop memory. These circuit elements are analogous to their solid-state electronic counterparts and could be used as components of control systems for integrated microfluidic devices. Such miniaturized fluidic circuits are insensitive to electromagnetic interference and may also find medical applications for implanted drug-delivery devices.     

Sleep and synaptic homeostasis: structural evidence in Drosophila

The functions of sleep remain elusive, but a strong link exists between sleep need and neuronal plasticity. We tested the hypothesis that plastic processes during wake lead to a net increase in synaptic strength and sleep is necessary for synaptic renormalization. We found that, in three Drosophila neuronal circuits, synapse size or number increases after a few hours of wake and decreases only if flies are allowed to sleep. A richer wake experience resulted in both larger synaptic growth and greater sleep need. Finally, we demonstrate that the gene Fmr1 (fragile X mental retardation 1) plays an important role in sleep-dependent synaptic renormalization.     

Design of Dynamic Sleep Communication Algorithm

在动态休眠通信算法中引入动态同步和休眠机制,减少了信道冲突并降低了系统时延;数据传输基于方向和剩余能量选择路由,均衡了网络的能量消耗,有效地延长了系统寿命.仿真实验结果表明,动态休眠通信算法具有较好的节能性.     

Priming and human memory systems

Priming is a nonconscious form of human memory, which is concerned with perceptual identification of words and objects and which has only recently been recognized as separate from other forms of memory or memory systems. It is currently under intense experimental scrutiny. Evidence is converging for the proposition that priming is an expression of a perceptual representation system that operates at a pre-semantic level; it emerges early in development, and access to it lacks the kind of flexibility characteristic of other cognitive memory systems. Conceptual priming, however, seems to be based on the operations of semantic memory.     

Hypothalamic Temperature in the Cat during Feeding and Sleep

Anterior hypothalamic temperature is reported for the unanesthetized cat resting at an air temperature of 22 degrees to 25 degrees C during the ingestion of cold or warm liquids, and during sleep. Drinking cold (5 degrees C) milk resulted in an immediate depression of hypothalamic temperature and a period of peripheral vasodilation in the ear and forepaw foot and toe pads, followed by a drop in rectal temperature. Drinking warm (body temperature) milk did not bring about these changes. Hypothalamic temperature during sleep is lower by approximately 0.5 degrees C and is characterized by widely varying, slow-frequency oscillations, compared to the higher, more precisely controlled temperature seen when the animal is awake.