Automated analyses of circadian rhythm activity of small arthropods

An automated apparatus is described which measures circadian activity rhythms of small invertebrates in darkness or in the presence of monochromatic light. Back-and-forth activity in tilt cages is measured without physical contact by magnet-activated reed switches. Four such cages are grouped around a mercury pen lamp, whose spectra lines can be selectively filtered, and all are placed in a large enclosure with light-baffling for complete control of intensity and color, delivered to each animal. Activity, measured as reed-switch closures, is counted digitally and punched out periodically onto paper tape. An interactive computer program reads, stores, plots, and further analyzes the data.     

Regions of response transition of color-coded retinal units and an attempted,analogy to behavioral response transition

Electrophysiological responses obtained from single color-coded red-green ganglion ceils of the goldfish retina were analyzed in terms of the spectral region within which response transitions occur. The data showed that criteria for response transitions can be characterized by a frequency change with the stipulation that the same number of “on” and “off” spikes occur to the same wavelength(s). The overall spectral band within which response transition occurs is 570–620 nm. The physiological response ranges were compared to psychophysical unique-yellow responses and other “yellow” judgments. The former were displaced towards the longer wavelengths as predicted by the different pigment peaks. The response characteristics of sharp boundaries and relative invariance with intensity changes provided the basis of an analogy of the two response systems.     

Color name as a function of wavelength and instruction

A series of experiments were performed to determine the effects of instructions upon color naming data. Although color name is basically a function of stimulus wavelength, even slight changes in the response categories available for the 5 led to substantial changes in the pattern of Ss’ response allocation.     

Pattern and orientation effects on afterimage duration

Patterns composed of a pair of lines: vertical + horizontal, vertical + oblique, horizontal + oblique, and oblique + oblique, either centrally-aligned or edge-aligned, were shown at two positions of rotation. After a 1-s exposure to the pattern observers timed the duration of afterimages consisting of individual lines (fragmentary state) and the pattern as a whole (unitary state) for the ensuring 60 s. Summing unitary and fragmentary afterimage durations yielded the total afterimage duration for each pattern. Three hypotheses were confirmed by the results: (i) total afterimage duration is constant for all patterns when integrated spatiotemporal luminances are equal; (ii) unitary afterimage duration is also constant; (iii) fragmentary afterimages of vertically oriented lines have longer durations than either their horizontal or oblique pair members, regardless of alignment and, with one exception, rotation. For all patterns, the durations of the unitary and the fragmentary state represent a fixed portion of the total afterimage duration. The difference between afterimage duration for differently oriented lines in patterns which include a vertical is discussed in relation to the vertical-horizontal illusion, the function and structure of cortical orientation processes, and perceptual development.     

Instrumentation of a self-luminous fixation annulus

A simple and inexpensive way of constructing a fixation annulus is described. Such a device is important for experiments in which a fixation spot in the test field area is undesirable or when subjects’ experimental tasks preclude their manipulation of a fixation dot brightness control. A luminous compound is inserted into transparent plastic tubing which can be shaped and inserted into a groove milled to fit the tube’s diameter and shape. Annulus luminance is in the scotopic range. Repeated measurement showed that there was no brightness loss over time. Ways of further attenuating brightness are discussed.