# gst: approaching the complex mechanics of crumpled sheets

<< Crumpling an ordinary thin sheet transforms it into a structure with unusual mechanical behaviors, such as logarithmic relaxation, emission of crackling noise, and memory retention. >>️

<< the response of crumpled sheets to cyclic strain is intermittent, hysteretic, and encodes a memory of the largest applied compression. (..) these behaviours emerge due to an interplay between localized and interacting geometric instabilities in the sheet. >>

<< after training multiple memories can be encoded, a phenomenon known as return point memory. >>

AA << study lays the foundation for understanding the complex mechanics of crumpled sheets, and presents an experimental and theoretical framework for the study of memory formation in systems of interacting instabilities. >>️️

Dor Shohat, Daniel Hexner, Yoav Lahini. Memory from coupled instabilities in crumpled sheets. arXiv: 2109.05212v1 [cond-mat.soft]. Sep 11, 2021.

https://arxiv.org/abs/2109.05212

keywords: gst, sheet, crumpled sheets, instability, bistability, memory, return point memory

# life: even a slime mold takes smart decisions about the future (Physarum polycephalum)

<< The slime mold Physarum polycephalum has been puzzling researchers for many decades. Existing at the crossroads between the kingdoms of animals, plants and fungi, this unique organism provides insight into the early evolutionary history of eukaryotes. Its body is a giant single cell made up of interconnected tubes that form intricate networks. This single amoeba-like cell may stretch several centimeters or even meters, featuring as the largest cell on earth in the Guinness Book of World Records. >>

<< The striking abilities of the slime mold to solve complex problems such as finding the shortest path through a maze earned it the attribute "intelligent," intrigued the research community and kindled questions about decision making on the most basic levels of life. >> 

<<  The decision-making ability of Physarum is especially fascinating given that its tubular network constantly undergoes fast reorganization—growing and disintegrating its tubes—while completely lacking an organizing center. The researchers discovered that the organism weaves memories of food encounters directly into the architecture of the network-like body and uses the stored information when making future decisions. >>

Researchers find a single-celled slime mold with no nervous system that remembers food locations. Max Planck Society. Feb 23, 2021.  

https://phys.org/news/2021-02-single-celled-slime-mold-nervous-food.html

Mirna Kramar, Karen Alim. Encoding memory in tube diameter hierarchy of living flow network. PNAS. 118 (10).  e2007815118. doi: 10.1073/ pnas.2007815118

https://www.pnas.org/content/118/10/e2007815118 

# brain: the drug ISRIB reverses age-related cognitive decline within days (in mice) and even enhance cognition in healthy animals

<< Just a few doses of an experimental drug can reverse age-related declines in memory and mental flexibility in mice, (..)  The drug, called ISRIB (ISR InhiBitor), has already been shown in laboratory studies to restore memory function months after traumatic brain injury (TBI), reverse cognitive impairments in Down Syndrome , prevent noise-related hearing loss, fight certain types of prostate cancer , and even enhance cognition in healthy animals. >>

<< In the new study, researchers showed rapid restoration of youthful cognitive abilities in aged mice, accompanied by a rejuvenation of brain and immune cells that could help explain improvements in brain function. >>

<< ISRIB's extremely rapid effects show for the first time that a significant component of age-related cognitive losses may be caused by a kind of reversible physiological "blockage" rather than more permanent degradation, >> Susanna Rosi.

<< The data suggest that the aged brain has not permanently lost essential cognitive capacities, as was commonly assumed, but rather that these cognitive resources are still there but have been somehow blocked, trapped by a vicious cycle of cellular stress, (..)  Our work with ISRIB demonstrates a way to break that cycle and restore cognitive abilities that had become walled off over time. >> Peter Walter.

Drug reverses age-related cognitive decline within days. University of California, San Francisco. Dec 01, 2020.

https://medicalxpress.com/news/2020-12-drug-reverses-age-related-cognitive-decline.html

Karen Krukowski, Amber Nolan, et al. 

Small molecule cognitive enhancer reverses age-related memory decline in mice. eLife. doi: 10.7554/ eLife.62048. Dec 1, 2020.

https://elifesciences.org/articles/62048  

# brain: the memory switch p75NTR

<< many molecular and environmental factors have been studied to understand how synaptic plasticity is modulated. Sleep, as an evolutionary conserved biological function, has shown to be a critical player for the consolidation and filtering of synaptic circuitry underlying memory traces. Although sleep disturbances do not alter normal memory consolidation, they may reflect fundamental circuit malfunctions that can play a significant role in exacerbating diseases, such as autism and Alzheimer's disease. (..) This paper will review the role of the p75NTR (p75 neurotrophic receptor), critically discuss the impact and implications of this research as the bridge for sleep research and neurological diseases.>>

Shen Ning, Mehdi Jorfi. p75NTR as a Molecular Memory Switch.  arXiv: 1912.11449v1 [q-bio.NC]. Dec 24, 2019.

https://arxiv.org/abs/1912.11449