Publication details
Investigation of summation mechanisms in the pupillomotor system
| Authors | |
|---|---|
| Year of publication | 2014 |
| Type | Article in Periodical |
| Magazine / Source | Graefes Archive for Clinical and Experimental Ophthalmology |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.1007/s00417-014-2677-4 |
| Field | ORL, ophthalmology, stomatology |
| Keywords | Pupil; Receptive field; Pupil perimetry; Campimetry |
| Description | To ascertain whether the pupillary response amplitude shows spatial summation of responses with increasing size of retinal stimulation, and to examine the pupillary responses for evidence of surround inhibition, analogous to that found in the receptive fields of the retinal ganglion cells. By means of infrared-video-pupillography, the pupil reaction to stimuli of increasing size (1-15A degrees) was measured in 30 normal subjects. Four different retinal locations (0A degrees, 20A degrees and 40A degrees eccentricity on the upper temporal retina and 20A degrees eccentricity on the lower nasal retina) were examined at four different stimulus luminances (17, 47, 87 and 140 cd/m(2)). When the average log amplitude of the pupil light reaction from the 30 subjects is plotted as a function of the log area of the stimulus, a bi-linear response is observed, which is most pronounced for the two higher luminances. The intersection points of the two linear responses are 2.01A degrees in the fovea, 2.80A degrees at 20A degrees upper temporal retina, 2.85A degrees at 20A degrees lower nasal retina and 4.86A degrees at 40A degrees upper temporal retina. This study suggests that pupillomotor summation areas consist of both summation and inhibitory zones. They show larger diameters than receptive fields of retinal ganglion cells and do not appear to reflect pupillary summation areas of the pretectal olivary nucleus luminance neurons. |