Living Scales: Communicating Across Scales: Biophysics and Beyond - Visual adaptation and perception, from the phototransduction cascade to cortical networks - Workshop
Life is inherently multi-scaled ranging from molecules (nm) to 100m (trees) and from femtoseconds (chemical reactions) to millennia (evolution), covering around 27 orders of magnitude in total. Thus ‘Scale’ creates immediate interdisciplinary resonances within current novel attempts to make progress understanding complex biological systems, especially by bringing the natural and life sciences communities together. Scale in biophysical systems also brings serious interdisciplinary challenges:
i. How can we measure structure and dynamics simultaneously at different scales?
ii. How can we build models that capture multiscale phenomena?
iii. How can we create holistic, ‘systems’ understanding even if we possess (i) and (ii)?
Durham strengths lie in macromolecular biophysics (McLeish, Quinlan) and bio imaging (Girkin) with a strong emphasis on vision science. Inviting imaginative and creative international fellows (Fricker and Smithson) into the Institute of Advanced Study and the Biophysical Science Institute communities looking at scale more widely will be extremely productive.
The current, highly reductionist, methodologies deployed in the natural sciences are in transition as they attempt to increase parameter space and length scales by building from the smallest scales up. In the science of inanimate soft matter and statistical mechanics, we are accustomed to emergent behaviour from smaller scales to larger (e.g. viscous fluid behaviour from mutually attractive molecules). However, the behaviour of individual proteins, genes, cells, even single gene networks, turns out increasingly to be coupled not only to other entities at their own level, but essentially upwards and downwards in scale. So, for example, gene transcription and post-translational modification within a cell nucleus can depend on tissue-scale stress fields which in turn can be linked with whole body stress. Such effects are common across the whole spectrum of life being seen in both plants and animal. Scale-coupling like this is crucially involved in pathologies such as cardiomyopathy and cancer as well as more sociological induced stresses. The complexities opened up by the interference of bottom-up and top-down coupling have yet to be explored. A muchmore holistic approach to, and view of, scale is needed in biological systems. This constitutes the core of the proposed sub-theme.
The close engagement of biological and physical sciences across length-scales is not only a better way of providing insight into biology questions. It also teaches new ideas to the logic of statistical physics, mathematics of complex systems and the phenomenon of emergence. The reciprocal coupling across scales discussed above has a different character even from those non-linear couplings that give rise to chaotic dynamics and related phenomena, and will enrich a number of communities in Durham working on complex systems (e.g. the Tipping Points team, members of the EPSRC network on Complex and Non-Equilibrium Systems).
Experimental investigations of biophysical systems at different spatial and temporal scales present additional challenges such as the 27 orders of magnitude mentioned above. This is turn generates questions of visualisation of such complex data sets. Logarithmic scales provides a solution which can work in two simple dimensions (i.e. a graph) - but other ways of representing information and structures across length scales invite investigation when one has living systems which inherently operate in four dimensions. This has significant links through to the analysis of highly complex data in fields such as banking, cosmology, particle physics, seismology and marketing information thus with links to iARC.
These questions are generating very early-stage research indicating that there is a rich seam to mine. An obvious extension, focussed on Durham interests, would be to explore the biophysical basis of visual perception from the molecular-level operation of photoreceptors, through local information-processing neuronal networks in the retina to system-level neuroscience. This system creates regulation of visual sensitivity over the 10^12-fold variation in environmental light levels under which human vision operates. This vast dynamic range is maintained through sensitivity adjustments at all levels in the visual system, from individual photoreceptors, to retinal circuits, and complex neural coding in cortex. A second strategic topic to explore within this field is imaging and modelling of self-organised, adaptive networks that operate from a sub-cellular level (cytoskeleton and endoplasmic reticulum), through embedded transport networks (leaf venation and blood vascular systems), to entire organisms that grow as networks (fungi and slime moulds).
These central ideas are the core of three workshops held during the Epiphany term under the ‘Living Scale’ sub-theme. Each will explore in a completely interdisciplinary way, one living example of a multi-scale, coupled system.
Workshop 1 - 9th and 10th January 2016 – Cosin’s Hall, IAS The Assembly, Dynamics and Organisation of Filaments and Cellular Responses
Workshop 2 - 8th February 2017 – Cosin’s Hall, IAS Multi-scale self-organised adaptive biological networks
Workshop 3 – 23rd – 24th March 2017 – Cosin’s Hall, IAS Visual adaptation and perception, from the phototransduction cascade to cortical networks
Vision is an important determinant of the quality of human life, so understanding the process from light entering the cornea through to the brain acting upon the visual information received is of crucial importance. The retina is "hard wired" into the brain. Incoming photons are guided by the physical structure of cells in the retina and some initial signal processing is undertaken on the retina before passing through to different levels of "signal" and "image" processing within the brain. This workshop will look at this process from light collection through to the images perceived by the subject and will also look at examples in which the image is created through sound rather than directly from light.
For further information about this workshop contact Professor John. Girkin (firstname.lastname@example.org), Professor Hannah Smithson (visiting IAS Fellow).
To book onto Workshop 3, please follow the link below;
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