News & Views
Magnetic particles have been made that undergo synchronized oscillations when suspended in liquid in a rotating magnetic field. This discovery links the fields of nonlinear dynamics and materials science. See Letter
The discovery of stone tools dating to 71,000 years ago at a site in South Africa suggests that the humans making them had developed the capacity for complex thought, and passed this knowledge down the generations. See Letter
Spectroscopic analysis reveals that, at low temperatures, hydrophobic molecules dissolved in water strengthen the hydrogen bonding between nearby water molecules. But at high temperatures, the reverse can be true. See Letter
Researchers have coaxed cultured embryonic stem cells to develop into eggs that then give rise to normal offspring. The discovery should help to decode the molecular basis of gamete formation and might lead to treatments for infertility.
Exposure to abnormal light–dark cycles causes depression-like behaviour and learning deficits in mice. The defects seem to occur independently of disturbances to sleep and other processes regulated by the biological clock. See Letter
The identification of a sea-floor microorganism that single-handedly conducts anaerobic oxidation of methane changes our picture of how the flux of this greenhouse gas from the ocean to the atmosphere is regulated. See Article
Cold and ultracold molecules provide fertile grounds for scientific discoveries. A method of cooling polyatomic molecules has been demonstrated that will allow researchers to explore the vast potential of these entities. See Letter
Hippocampal ripples, episodic high-frequency field-potential oscillations primarily occurring during sleep and calmness, have been described in mice, rats, rabbits, monkeys and humans, and so far they have been associated with retention of previously acquired awake experience. Although hippocampal ripples have been studied in detail using neurophysiological methods, the global effects of ripples on the entire brain remain elusive, primarily owing to a lack of methodologies permitting concurrent hippocampal recordings and whole-brain activity mapping. By combining electrophysiological recordings in hippocampus with ripple-triggered functional magnetic resonance imaging, here we show that most of the cerebral cortex is selectively activated during the ripples, whereas most diencephalic, midbrain and brainstem regions are strongly and consistently inhibited. Analysis of regional temporal response patterns indicates that thalamic activity suppression precedes the hippocampal population burst, which itself is temporally bounded by massive activations of association and primary cortical areas. These findings suggest that during off-line memory consolidation, synergistic thalamocortical activity may be orchestrating a privileged interaction state between hippocampus and cortex by silencing the output of subcortical centres involved in sensory processing or potentially mediating procedural learning. Such a mechanism would cause minimal interference, enabling consolidation of hippocampus-dependent memory.
Regulatory T (Treg) cells, characterized by expression of the transcription factor forkhead box P3 (Foxp3), maintain immune homeostasis by suppressing self-destructive immune responses