Since consciousness is spread across multiple brain regions, it’s possible for one part of the brain to respond while others are entirely unresponsive. One way to think about this is the starter on a damaged car engine still working even though gas can’t reach the engine; a minimal “signal” from the starter is produced by turning the key, even though the engine can’t run.
The new tool, developed by researchers from Italy’s University of Milan, could provide doctors with a more objective method that gauges the complexity of a patient’s consciousness. The tool combines three steps: first a magnetic pulse is sent through a coil into the brain designed to “wake it up,” and then an EEG machine measures brain wave activity produced by neurons firing in response to the pulse. Finally, the activity is measured via a formula that puts a finer point on the nature of the patient’s consciousness.
That final step is the secret ingredient that makes this tool different: instead of simply trying to identify brain activity (something MRI machines can already do) it produces a measure of the complexity of consciousness–what the researchers call the perturbational complexity index (PCI). “Consciousness can grow and shrink,” said Dr. Marcello Massimini, a neurophysiologist who led the research, in an AP report about the experimental tool. By figuring out the level of “growing” or “shrinking”, doctors can more objectively gauge whether a patient is exhibiting an adequate level of consciousness to recover.
The researchers emphasized that the tool is far from becoming a bedside medical option, but the research opens the door to measuring levels of consciousness that correlate with recovery from serious brain injury. This knowledge could potentially change the way end-of-life decisions are made by providing doctors and loved ones with a firmer means to evaluate whether a patient has the capacity to recover.
The study was published in the journal, Science Translational Medicine.
10. The Antidepressant Sweet Spot for Coffee Drinkers
Coffee research is a crap shoot at best – every year new studies come out suggesting benefits and drawbacks of our favorite morning companion. But in 2013, researchers from the Harvard School of Public Health made an especially significant contribution to coffee research that found a correlation between drinking 2-4 cups of caffeinated coffee each day and lower suicide risk among adults.
The study, published in The World Journal of Biological Psychiatry, was a meta-review of three extensive U.S. health studies that included a total of 43,599 men and 164,825 women. Consumption of caffeine (from tea, soda and chocolate), coffee and decaffeinated coffee was evaluated among study participants every four years via questionnaire. Across all three studies, coffee accounted for the majority of caffeine consumed at 71% of the total.
Causes of death were tracked during the study period by reviewing death certificates; 277 deaths were the result of suicide.
The analysis showed that the risk of suicide among adults drinking 2-4 cups of coffee (the equivalent of about 400 mg of caffeine) a day was 50% less than the risk for adults who drank decaffeinated coffee or one cup or less of caffeinated coffee. Drinking more than 4 cups of coffee wasn’t associated with lower suicide risk.
The neurochemistry behind the finding makes sense. As discussed in a previous article, caffeine acts as an expert mimic of a chemical called adenosine in the brain and other parts of the body. Adenosine is a sort of checks-and-balances chemical produced by neurons as they fire throughout the day; the more adenosine is produced, the more the nervous system ratchets down activity, until we eventually fall asleep and reboot the process.
By mimicking adenosine, caffeine blocks receptors in the nervous system from receiving the signals to decrease energy expenditure. When that happens, levels of the brain’s homegrown neuro-stimulants—dopamine and glutamate—increase, and we experience the brain stimulating effects associated with drinking a big cup of java. Those effects may be a potent counterbalance to depression for a segment of the coffee-drinking population.
Have more studies you’d like to add to this list or comments on any of those above? Please put them in the comments section for all to see. Thanks!
You can find David DiSalvo on Twitter @neuronarrative and at his website, The Daily Brain. His latest book is Brain Changer: How Harnessing Your Brain’s Power To Adapt Can Change Your Life.
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