Note on the Spectroscopy of Subjective Light Patterns

The hypnagogic state: A critical review of the literature.

“…Ladd 1892, McKellar and Simpson (1954), and Sartre (1972) presented thorough discussions of the relationship between the entoptic lights and the formation of visual hypnagogic images. The material gathered in studies of electrically stimulated phosphenes (Knoll, Kugler, Eichmeier, & Hofer, 1962) closely resembles the designs and patterns reported in this stage of the hypnagogic state, thus lending support to the contention that the entoptic phenomena play a major role in generating the geometriclike images.…”

Effects of Chemical Stimulation of Electrically-Induced Phosphenes on their Bandwidth, Shape, Number and Intensity

“…(4) W hereas, as found in earlier work (K noll 1958, 1959, 1962) [26,29,30,28], electrically-induced phosphenes h av e m ostly the shape of ab stra ct-or ornam ental-type p a tte rn s, w ith only v ibrational-or re p eatin g -ty p e m ovem ent, th e drug-induced phenom ena also include landscapes and living or m an-m ade objects such as flowers, anim als, m achines and fast-m oving " firew ork" -type p a tte rn s.…”

“…L ately, (1958 [26]; 1959 [29]; 1959 [30]; 1962 [28]) b y using re c ta n g ular pulse frequencies w ith in th e E E G -range an d large (2 x 4 cm) tem p o ral or occipital electrodes, an objective m ethod has been devel oped which perm its th e ex citatio n an d control of phosphenes b y ex posing th e b ra in to electrical fields w ith o u t brain surgery. T he b a n d w id th of such p a tte rn s observed b y th e sam e individual has been found to v a ry (in all subjects investigated) only betw een 1 and 2 0 % of th e m ean frequency of th e pulse c u rre n t exciting them .…”

Recent advances in the neuropsychopharmacology of serotonergic hallucinogens

“…Heinrich Klüver (1928) was the first to recognize that all of the elementary geometric hallucinations induced by mescaline are elaborated variations of four basic forms, which he called form constants : (a) tunnels and funnels, (b) spirals, (c) lattices and checkerboards, and (d) cobwebs. The form constants are not unique to hallucinogens and can occur during a variety of hallucinatory states, including migraine aura (Sacks, 1995), epilepsy (Horowitz et al, 1967), sensory isolation (Heron et al, 1956), viewing flickering light (Becker and Elliott, 2006; Allefeld et al, 2011), and electrical cortical stimulation (Knoll et al, 1962; Horowitz et al, 1968). …”