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COMPLEX TIME: Adaptation, Aging, & Arrow of Time

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What is Sleep?/CeciliaDinizBehn

From Complex Time

Notes by user Cecilia Diniz Behn (Colorado School of Mines) for What is Sleep?

Post-meeting Reflection

1+ paragraphs on any combination of the following:

  • Presentation highlights
  • Open questions that came up
  • How your perspective changed
  • Impact on your own work
  • e.g. the discussion on [A] that we are having reminds me of [B] conference/[C] initiative/[D] funding call-for-proposal/[E] research group

Big idea: consideration of multifactorial definition of and function of sleep

Susan Sara: Hippocampal ripples are important for memory consolidation; how would the timing of increased ripple density post-learning change with species and/or development? Can this be connected to brain size/networks involved in memory consolidation?

Gina Poe: How are memories tagged for strengthening or weakening? What computational approaches could inform our understanding of this? Complexity of memory likely influences the time scale - how might we explore this experimentally or computationally?

Sara Aton: Mechanism whereby a rate code is translated to a phase code. How does modulation of neurotransmitter milieu affect the propensity of network to propagate particular rhythms? How does the power of rhythms relate to metabolic rate of the brain? Does synchrony play a role?

Kimberley Whitehead: How do mechanisms for spindle-burst production relate to mechanisms for spindle production? What are appropriate comparisons for pre-term human infants and animal models of different species (rat, sheep, etc.)?

Beth Klerman: Seasonality is observed in the duration of the biological night as measured with melatonin expression; how does this relate to mechanisms for seasonality encoded in the SCN? Important new direction to take insights from groups and translate this to predictions for individuals? How do we handle missing data and investigate the tolerance of models to missing data?

Victoria Booth: What do changes in the structure of sleep tell us about changes in physiology? Blumberg showed a lack of consolidation of wake in OXKO infant mice emerged during development when WT mice were able to consolidate wake bouts to transition to a power-law-like behavior. We showed similar differences in a mouse model with acute orexin cell loss (Branch et al., SLEEP, 2016). What can we learn about sleep in development in the absence of orexin neurons? How would physical distance between neuronal populations and degree of myelination affect the time scales on which these populations interact? For example, would slower transmission allow more bistability between states? Neonates have more wake to REM sleep transitions. How would we understand this in terms of different network configurations for NREM/REM regulation? Would this be a useful constraint?

Jerry Siegel: Fur seals can switch between bihemispheric sleep and unihemispheric sleep. Modeling has suggested that this can be understood based on relative strengths of contralateral and ipsilateral connections between brain hemispheres (Kedziora et al., J of Theoretical Biology, 2012). How do predictions compare to anatomical evidence? What other insights from physiology could we get from this system? Important to consider the role of temperature and thermoregulation in sleep dynamics. This has been explored a bit in a recent model (Banuelos et al., Effects of Thermoregulation on Human Sleep Patterns: A Mathematical Model of Sleep–Wake Cycles with REM–NREM Subcircuit, in Applications of Dynamical Systems in Biology and Medicine pp 123-147). What are other ways that these ideas could be included in mathematical models of sleep?

Van Savage: What can theory tell us about the quantities we should be measuring experimentally? For example, the theory suggests the importance of considering the ratio of time asleep to time awake rather than durations only.

Geoffrey West: Developing a theory that connects sleep duration and lifespan. Lifespan scaling is derived from ideas of sleep for repair; could we introduce a modification that involves a different role for sleep in development? How is this impacted by differences in species development/maturity? Can we understand this scaling in terms of the DNA methylation view of aging (e.g., converting dog years to human years:

Alex Herman: If synaptic density drives metabolic rate of the brain, is there also a role for different rhythms? Reporting a sharp transition in the relationship between the ratio of time asleep/time awake to brain mass. What else does this transition correlate with? Changes in behavior? What would this be abrupt and not graduate? What does synaptogenesis peak and how does it relate to this transition? Follow up with Junwu Can regarding her method for threshold detection of this transition.

Bob Stickgold: Different types of sleep for different types of learning; gist words - how does this relate to other measures of creative thinking? What is the role of forgetting for dreams and what is important about the dreams we remember? What about problem solving that can occur while sleeping/dreaming?

Reference material notes

Some examples:

  • Here is [A] database on [B] that I pull data from to do [C] analysis that might be of interest to this group (insert link).
  • Here is a free tool for calculating [ABC] (insert link)
  • This painting/sculpture/forms of artwork is emblematic to our discussion on [X]!
  • Schwartz et al. 2017 offers a review on [ABC] migration as relate to climatic factors (add the reference as well).

Reference Materials

Title Author name Source name Year Citation count From Scopus. Refreshed every 5 days. Page views Related file
Modeling the temporal architecture of rat sleep-wake behavior. Cecilia G. Diniz Behn, Victoria Booth Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 2011 0 2 Download
Effects of thermoregulation on human sleep patterns a mathematical model Selenne Bañuelos, Janet Best, Gemma Huguet, Alicia Prieto-Langarica, Pamela B. Pyzza, Markus H. Schmidt, Shelby Wilson 2015 0 5 Download