Lifeboat Foundation

An important aspect of human memory is our ability to conjure specific moments from the vast array of experiences that have occurred in any given setting. For example, if asked to recommend a tourist itinerary for a city you have visited many times, your brain somehow enables you to selectively recall and distinguish specific memories from your different trips to provide an answer.

Studies have shown that declarative memory—the kind of memory you can consciously recall like your home address or your mother’s name—relies on healthy medial temporal lobe structures in the brain, including the hippocampus and entorhinal cortex (EC). These regions are also important for spatial cognition, demonstrated by the Nobel-Prize-winning discovery of “place cells” and “grid cells” in these regions—neurons that activate to represent specific locations in the environment during navigation (akin to a GPS). However, it has not been clear if or how this “spatial map” in the brain relates to a person’s memory of events at those locations, and how neuronal activity in these regions enables us to target a particular memory for retrieval among related experiences.

A team led by neuroengineers at Columbia Engineering has found the first evidence that individual neurons in the human brain target specific memories during recall. They studied recordings in neurosurgical patients who had electrodes implanted in their brains and examined how the patients’ brain signals corresponded to their behavior while performing a virtual-reality (VR) object-location memory task. The researchers identified “memory-trace cells” whose activity was spatially tuned to the location where subjects remembered encountering specific objects. The study is published today in Nature Neuroscience.

Both humans and mice respond to fear in ways that are deeply etched in survival mechanisms that have evolved over millions of years. Feeling afraid is part of a response that helps us to survive; we learn to respond appropriately, based on our assessment of the danger we face. Importantly, part of this response involves extinguishing fear and modifying our behavior accordingly, once we have learned that a potential threat poses little or no imminent danger. The inability to adapt to fears or lay them aside is involved in disorders such as PTSD and anxiety.

The researchers from Weill Cornell demonstrated that changes in the microbiome can result in an impaired ability to extinguish fear. This was true of two groups of mice: one group had been treated with antibiotics; the other group was raised entirely free of germs. The ability of both groups of mice to extinguish fear was compared with that of control mice whose microbiome was not altered. The difference suggested that signals from the microbiome were necessary for optimal extinction of conditioned fear responses.

New gene-editing documentary showcases biology’s hottest tool — up to the point when things went awry. By Amy Maxmen.

A worrisome report from 2013 generated new fears several years later.

A team of researchers from the University of Sheffield in the UK has identified a protein that plays a key role in the development of atherosclerosis, the leading cause of death worldwide.

The trouble with Tribbles 1

Researchers have demonstrated for the first time that the protein known as Tribbles 1 (TRIB1) is expressed by macrophage that is linked to the formation of the plaques that clog our arteries and eventually kill us. Macrophages are responsible for removing cellular garbage and other waste from our bodies to keep us healthy, and that includes the insides of our arteries.

While the public is still imagining the future to be very much like the past, the researchers at the forefront of genetics are planning to redesign human bodies, to make us more long-lived, more resilient to disease, more strong and (I hope) more intelligent.

In a talk at Exponential Medicine, Jane Metcalfe said that tools like gene editing and synthetic biology could make design the next big thing in medicine.

North Americans spent more than $936 million on vitamin D pills in 2017, doctors ordered more than 10 million laboratory tests for vitamin D for Medicare patients at a cost of $365 million in 2016, and 25 percent of older adults take vitamin D supplements. A Kaiser Health News investigation recently reported that the man most responsible for the obsession with vitamin D pills, Boston endocrinologist Michael Holick, has been paid hundreds of thousands of dollars by supplement and drug manufacturers, the indoor-tanning industry and commercial laboratories that run blood tests for vitamin D (New York Times, August 18, 2018). Many doctors have been concerned about the recommendations for very high doses of vitamin D for a long time. In 2004, highly-respected Dr. Barbara Gilchrest, then head of Boston University’s Department of Dermatology, asked Holick to resign from the department. In 2014, the U.S. Preventive Services Task Force reported that there is not enough evidence to recommend routine vitamin D testing. In 2015, Excellus BlueCross BlueShield reported that they had spent $33 million on 641,000 vitamin D tests.

No Benefits Shown in Recent Studies • Vitamin D pills were not shown to help prevent heart attacks or cancer: A study led by a Harvard researcher, Dr. Joanne Manson, followed 25,871 men and women for a median of 5.3 years. Participants who took vitamin D3 (cholecalciferol), 2000 IU per day, had no added protection from heart diseases or cancers (NEJM, November 10, 2018).

The cells in your body are like computer software: they’re “programmed” to carry out specific functions at specific times. If we can better understand this process, we could unlock the ability to reprogram cells ourselves, says computational biologist Sara-Jane Dunn. In a talk from the cutting-edge of science, she explains how her team is studying embryonic stem cells to gain a new understanding of the biological programs that power life — and develop “living software” that could transform medicine, agriculture and energy.

This talk was presented at an official TED conference, and was featured by our editors on the home page.

Biology encodes information in DNA and RNA, which are complex molecules finely tuned to their functions. But are they the only way to store hereditary molecular information? Some scientists believe life as we know it could not have existed before there were nucleic acids, thus understanding how they came to exist on the primitive Earth is a fundamental goal of basic research. The central role of nucleic acids in biological information flow also makes them key targets for pharmaceutical research, and synthetic molecules mimicking nucleic acids form the basis of many treatments for viral diseases, including HIV. Other nucleic acid-like polymers are known, yet much remains unknown regarding possible alternatives for hereditary information storage. Using sophisticated computational methods, scientists from the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology, the German Aerospace Center (DLR) and Emory University explored the “chemical neighbourhood” of nucleic acid analogues. Surprisingly, they found well over a million variants, suggesting a vast unexplored universe of chemistry relevant to pharmacology, biochemistry and efforts to understand the origins of life. The molecules revealed by this study could be further modified to gives hundreds of millions of potential pharmaceutical drug leads.

Nucleic acids were first identified in the 19^th century, but their composition, biological role and function were not understood by scientists until the 20^th century. The discovery of DNA’s double-helical structure by Watson and Crick in 1953 revealed a simple explanation for how biology and evolution function. All living things on Earth store information in DNA, which consists of two polymer strands wrapped around each other like a caduceus, with each strand being the complement of the other. When the strands are pulled apart, copying the complement on either template results in two copies of the original. The DNA polymer itself is composed of a sequence of “letters,” the bases adenine (A), guanine (G), cytosine © and thymine (T), and living organisms have evolved ways to make sure during DNA copying that the appropriate sequence of letters is almost always reproduced. The sequence of bases is copied into RNA by proteins, which then is read into a protein sequence.