Memories don’t pass from short term to long term; all of our different memory types coexist

A study by New York University (NYU) scientists has concluded that memory, rather than being a complete store of past events, is composed of a vast repertoire of coexisting time windows.

Most memories last seconds before they are forgotten, but some last a lifetime. However, the scientists Thomas Carew and Nikolay Kukushkin have concluded that rather than going from short term to long term, both types of memories coexist.

So, for example, a familiar musical piece is experienced simultaneously through the short-term memory of the few notes just heard and the long-term memory of listening to the piece in the past. Both retain information about the past, they write, and both shape perception in the present.

“Much like sound is broken down by the auditory system into many discrete bins of frequencies that are perceived simultaneously, an experience as a whole is parsed by the brain into many ‘time windows’ that collectively represent the past,” said Carew, a professor in NYU’s Center for Neural Science and dean of the Faculty of Arts and Science.

Image courtesy of University of Florida

As a result of their research, Carew and Kukushkin believe memory cannot be restricted to a defined object or state; instead, it is fundamentally structured in terms of time.

The scientists note that brains of living organisms – as diverse as sea slugs and humans – have the capacity to represent experience on many timescales, simultaneously recalling events occurring over years, hours, and milliseconds.

“Time is the only physical variable that is ‘inherited’ by the brain from the external world,” the scientists conclude. “Thus, memories must be ‘made of time,’ or, more precisely, of temporal relationships between external stimuli.

“In effect, the entire biological utility of memory relies on the existence of many dimensions of homeostasis, some shorter-term and some longer-term. The many timescales of memory represent many timescales of past experience and must be simultaneously available to the organism to be useful.”

 

Breathable electronic skin patch developed for continuous long-term use

Scientists have developed an electronic sensor that is hypoallergenic, breathable and can be worn constantly for a week, enabling continuous, unobtrusive health monitoring.

The patch, developed by scientists at the University of Tokyo, is, according to its creators, so thin and light that the majority of users will forget they are even wearing it – a far cry from many of the weighty or uncomfortable health monitoring solutions currently available.

Designed to withstand repeated and continuous bending and stretching, the patch can be worn during a host of day-to-day activities, including sports. As a result its creators believe it could be used not only in healthcare settings, but also to monitor professional athletes.

“It will become possible to monitor patients’ vital signs without causing any stress or discomfort,” said Professor Takao Someya, from the University of Tokyo’s Graduate School of Engineering.

The patch, which is detailed in research published today in the journal Nature Nanotechnology, is a step forward due to its breathable properties, allowing it to be worn for far longer than other ultrathin patches, which are made of rubber and other similarly non-breathable materials.

It consists of an electrode made up of several nanoscale meshes, which contain a water-soluble polymer, polyvinyl alcohol (PVA) and a thin layer of gold.

The patch is applied to the skin by spraying it with a thin layer of water, which dissolves the PVA and leaves the patch able to stick to the skin. It is even designed to adhere to the minute bumps in the skin, including sweat pores and the ridges that form human fingerprints, allowing a snug fit and good long-term attachment.

Currently it has been tested on 20 study participants, who wore the patch for a week. Not one experienced any inflammation, suggesting the patch should be suitable for wide-scale medical use.

It was also successfully bent and stretched over 10,000 times without damage, and was successfully used as an electrode to record electromyogram readings, which measure the electrical activity muscles, at similar levels to standard gel electrodes.

A diagram showing how the patch adheres to the skin. Images courtesy of Someya Laboratory, 2017.

The scientists have previously developed a patch that measures blood oxygen, and decided to create this variant upon realising the significant medical need for comfortable patches that can be worn constantly for significant periods.

“We learned that devices that can be worn for a week or longer for continuous monitoring were needed for practical use in medical and sports applications,” said Someya.

While the headline use for the patch will undoubtedly be in medical settings, it is also likely to attract considerable interest in the world of professional sports, where monitoring athletes is becoming increasingly commonplace.

 

At present, most of the wearables used to monitor athletes are housed in plastic units that are temporarily attached to the skin using harnesses or pockets in sports equipment, however such a patch could enable a less obtrusive approach to monitoring.