Month: September 2022

CONE SHELL PHYLOGENIES. “The species have a well supported phylogeny that allows us to infer rates and patterns of parameter evolution.” https://lnkd.in/dwfZQzE View in LinkedIn

GANGLIONIC RING. “Fig. 1. The neural-network model of the mantle. (A) Rough anatomy of a generic shelled mollusk. Note the “brain,” where the neural patterns are processed consists of a ring of ganglia.” https://lnkd.in/dwfZQzE View in LinkedIn

TASTING PATTERNS. “Fig 1. (B) Cross-section of the mantle showing how the sensory cells “taste” the previously laid pigment patterns that are processed by the central ganglion and sent to the mantle network that controls the pigment-secreting cells.” https://lnkd.in/dwfZQzE View in LinkedIn

PATTERN GENERATION. “Fig 1. (C) Simple pattern on a Conus shell and how the model extrapolates the previous pattern to produce the current day's pigment secretion. The pigmentation pattern is read by the sensory cells in the mantle. This activity is then passed through the space–time filter of neural activation and inhibition.” https://lnkd.in/dwfZQzE View in LinkedIn

SHELL SPACETIME. “Time represents the pigmentation pattern that was laid down in previous bouts, whereas space is the dimension along the growing edge of the cell. The resulting filtered activity is passed through nonlinearities for excitation and inhibition, and this net activity drives the secretory cells that lay down the new pigmented shell material.” https://lnkd.in/dwfZQzE View in LinkedIn

SPACE AND TIME FILTERS. “The spatial filter, shown in top and perspective views, has the form of a Mexican hat, in which excitatory activity stimulates a surrounding inhibitory field. The temporal filter that implements delayed inhibition is half a Mexican hat. It generates a refractory period following a period of activity. “ https://lnkd.in/dwfZQzE View in LinkedIn

THE PIGMENT CYCLE. “The pigment secreting cells have a sigmoidal stimulus response curve. Feedback occurs as the current pigment deposition becomes part of the input to the sensory cells for the next secretion bout.” https://lnkd.in/dwfZQzE View in LinkedIn

BETWEEN NOISE AND CHAOS. “Fig. 3. (A) Both noise and chaos generate within-species pattern diversity. a, Three real C. crocatus shells. b, Three shells generated with 1% noise only. c, Three shells generated with slightly different initial conditions, but no noise. d, Three shells with both 1% noise and slightly different initial conditions. (B) Two examples of “unknown” patterns having too-wide inhibition fields. https://lnkd.in/dwfZQzE View in LinkedIn

LATERAL INHIBITION. “Somewhat surprisingly, the regions of parameter space that correspond to cone shell patterns are fairly restricted and almost always require that the effective spatial interaction be lateral inhibition. When we chose parameters outside this range, we produced shell patterns that do not correspond to any known species.” https://lnkd.in/dwfZQzE View in LinkedIn

NATURE OF PATTERNING. “Structural studies provide strong evidence that shell patterns are a neurosecretory phenomenon rather than a diffusing morphogen phenomenon.” https://lnkd.in/dwfZQzE View in LinkedIn