Electrical Stimulation Wakes the Minimally Conscious at Home
Both deep brain stimulation and transcranial direct current stimulation (tDCS) have been used to increase awareness and responsiveness in minimally conscious patients. One of the research teams has taken the equipment to at-home patients and trained their caregivers to use it. After four weeks of administering stimulation for 20 minutes every weekday, one-fifth of the patients showed improvement. They were able to respond to yes/no questions with hand gestures or eye blinks; one laughed at jokes and humorous scenes on TV. Stimulation is delivered over the frontal lobes, which are a hub for the default mode network. After stimulation the individual gradually returns to the pre-treatment state, but it might be possible to prolong the periods with lengthier stimulation. Brain Stimulation, DOI: https://doi.org/10.1016/j.brs.2018.04.021 (article in press).

How Researchers Think About Consciousness
The difficulty of coming to a concensus about what consciousness means is illustrated by an article examining several researchers' different takes on what consitutes the most basic component of consciousness and which animals have it. According to Bjørn Grinde, differential emotional responses to good and bad experiences represents the dawn of consciousnes. For example ammals, birds, and reptiles all show elevated heart rate and temperature when handled, but fish and amphibians do not. Bruno van Swinderen is betting on selective focus of attention, which is seen in vertebrates, insects, crustaceans, and octupuses, but probably not starfish, worms, and jellyfish. But Micahel Graziano thinks this is not enough, that you need to have a model of attention, which includes the ability to understand you're focusing your attention. To Eva Jablonka, the marker for the origin of consciousness is unlimited asociative learning. This capacity subsumes selective attention and the abilities to combine sensations into one perception, perform compound action patterns, and distinguish self from environment. This definition would admit most vertebrates, insects, crustaceans, octopuses and, perhaps, some snails. We're not sure about other animals, due to a lack of data. Don't look for a definition of consciousness any time soon, but do expect a lot of research coming from these ideas. And that's a good thing. New Scientist, May 10, 2017.





Brief Weightlessness Alters the Default Mode Network and Body Consciousness
We orient ourselves in space by integrating sensory information about the body and the environment in the right temporo-parietal junction (rTPJ). Weightlessness experienced in space results in spatial disorientation early in flight and again on the return to earth. The ability to produce weightlessness during parabolic flights, in which an airplane repeatedly descends rapidly from higher altitudes, provided the opportunity for researchers to study how this experience affects the brain. Volunteers underwent MRI scans before and after flight. Even though total time of weightlessness amounted to only 10 minutes, post-flight activity was reduced in the rTPJ, presumably as a reaction to conflicting inputs. In addition, reduced connectivity occurred in the default mode network, which is important for cognitive processing and level of consciousness. Nature Scientific Reports, DOI:10.1038/s41598-017-03170-5.

Melatonin Promotes Sleep by Inhibiting Orexin Neurons
Endogenous melatonin has long been known to promote sleep, and pharmaceutical melatonin is a popular over-the-counter sleep aid. But until now we haven't known how it works. Infusing melatonin into the perifornical lateral hyothalamus induced sleepfulness in mice, indicating to researchers at the University of Missouri School of Medicine that it inhibits orexin neurons. Infusing the melatonin receptor antagonist luzindole into the area increased wakefulness. Pineal Research, DOI: 10.1111/jpi.12498.

Genetic Links Between Sleep Problems and Other Disorders
Sleep disorders often occur alongside psychological and physical disorders, leading to the frequent suggestion that inadequate sleep contributes to the second health problem. But a massive study of 33,000 soldiers places some of the blame on genes, after finding that insomnia is genetically linked to type 2 diabetes and to major depression. Molecular Psychiatry, DOI: 10.1038/s41380-018-0033-5

Faulty Sleep Interferes With Memory in the Elderly
Slow waves synchronize with the faster sleep spindles hundreds of times a night; this synchrony has been proposed to support consolidation, but there has been little evidence for this in humans. Berkeley researchers studying young and older adults found that the quality of this coordination predicts overnight memory retention. Age-related atropy in the medial frontal cortex in the older subjects was correlated with desynchronization, impaired overnight memory consolidation, and forgetting. Neuron, Vol 97, 221-230.