Fascinating. Thanks, Stephen. That seems exactly on point. I experience number 3.
Incidentally, I appreciate your sympathy. Fortunately, I experience no pain with these hallucinations. Frank ----------------------------------- Frank Wimberly My memoir: https://www.amazon.com/author/frankwimberly My scientific publications: https://www.researchgate.net/profile/Frank_Wimberly2 Phone (505) 670-9918 On Mon, May 6, 2019, 3:44 PM Stephen Guerin <[email protected]> wrote: > Frank, > > Sorry you're experiencing migraines - no fun! On the upside, the > mathematician in you may appreciate the opportunity of direct observation > of potentially interesting feedback phenomena. > > Jack Cowan, one of Stu's mentors, gave a nice talk at BioGroups back in > 2001 on geometric patterns during hallucination due to instabilities > driving the feedback structures of the visual cortex. Jack had a couple > papers paper was with Paul Bressloff. Utah Math Department ( > https://www.math.utah.edu/~bresslof/) Marty Golubitsky, co-author with > Ian Stewart of Fearful Symmetry > <https://www.amazon.com/Fearful-Symmetry-Geometer-Dover-Mathematics/dp/0486477584>, > and Peter Thomas <https://case.edu/math/thomas/>Case Western > > paper here: https://www.math.uh.edu/~dynamics/reprints/papers/nc.pdf. > related paper here: > https://royalsocietypublishing.org/doi/abs/10.1098/rstb.2000.0769 > > What geometric visual hallucinations tell us about the visual cortex > Paul C. Bressloff, Jack D. Cowan*, Martin Golubitsky, Peter J. Thomas and > Matthew C. Wiener > > ABSTRACT: > Geometric visual hallucinations are seen by many observers after taking > hal- lucinogens such as LSD, cannabis, mescaline or psilocybin, on viewing > bright flickering lights, on waking up or falling asleep, in “near death” > experiences, and in many other syndromes. Klu ̈ver organized the images > into four groups called “form constants”: (1) tunnels and funnels, (2) > spirals, (3) lattices, including honeycombs and triangles, and (4) cobwebs. > In general the images do not move with the eyes. We interpret this to mean > that they are generated in the brain. Here we present a theory of their > origin in visual cortex (area V1), based on the assumption that the form of > the retino-cortical map and the architecture of V1 determine their > geometry. We model V1 as the continuum limit of a lattice of interconnected > hypercolumns, each of which itself comprises a number of interconnected > iso-orientation columns. Based on anatomical evidence we assume that the > lateral connectivity between hypercolumns exhibits symmetries rendering it > invariant under the action of the Euclidean group E(2), composed of > reflections and translations in the plane, and a (novel) shift–twist > action. Using this symmetry, we show that the various patterns of activity > that spontaneously emerge when V1’s spatially uniform resting state becomes > unstable, correspond to the form constants when transformed to the visual > field using the retino–cortical map. The results are sensitive to the > detailed specification of the lateral connectivity and suggest that the > cortical mechanisms which generate geometric visual hallucinations are > closely related to those used to process edges, contours, textures and > surfaces. > > > _______________________________________________________________________ > [email protected] <[email protected]> > CEO, Simtable http://www.simtable.com > 1600 Lena St #D1, Santa Fe, NM 87505 > office: (505)995-0206 mobile: (505)577-5828 > twitter: @simtable > > > On Mon, May 6, 2019 at 1:39 PM Frank Wimberly <[email protected]> wrote: > >> Also called optical migraines. I experience them as perfect, complex, >> geometric patterns which scintillate and exhibit various colors. How does >> that come about from the glop that is my brain or retina or whatever? It's >> all glop. >> >> Frank >> >> ----------------------------------- >> Frank Wimberly >> >> My memoir: >> https://www.amazon.com/author/frankwimberly >> >> My scientific publications: >> https://www.researchgate.net/profile/Frank_Wimberly2 >> >> Phone (505) 670-9918 >> ============================================================ >> FRIAM Applied Complexity Group listserv >> Meets Fridays 9a-11:30 at cafe at St. John's College >> to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com >> archives back to 2003: http://friam.471366.n2.nabble.com/ >> FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove >> > ============================================================ > FRIAM Applied Complexity Group listserv > Meets Fridays 9a-11:30 at cafe at St. John's College > to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com > archives back to 2003: http://friam.471366.n2.nabble.com/ > FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove >
============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College to unsubscribe http://redfish.com/mailman/listinfo/friam_redfish.com archives back to 2003: http://friam.471366.n2.nabble.com/ FRIAM-COMIC http://friam-comic.blogspot.com/ by Dr. Strangelove
