Subjective and Electroretinographic Dynamics of Light Adaptation in the Human Visual System.

The excitation of the visual system increases with increasing retinal illumination. At the same time, the sensitivity of the system decreases (light adaptation). Higher excitation automatically results in a lower sensitivity.

A model of the FAD redox cycle describes the dynamics of the effect of the geomagnetic field on the human visual system.

In experimental studies, we could show that the visual threshold of man is influenced by the geomagnetic field. One of the results was that the threshold shows periodic fluctuations when the vertical component of the field is reversed periodically. The maximum of these oscillations occurred at a period duration of 110 s.

The effect of motor-respiratory coordination on the precision of tracking movements: influence of attention, task complexity and training.

Purpose: We investigated motor-respiratory coordination (MRC) in visually guided forearm tracking movements focusing on two main questions: (1) Does attentional demand, training or complexity of the tracking task have an effect on the degree of MRC? (2) Does MRC impair the precision of those movements? We hypothesized that (1) enhanced attention to the tracking task and training increase the degree of MRC while higher task complexity would reduce it, and (2) MRC impairs tracking precision.

Methods: Thirty-five volunteers performed eight tracking trials with several conditions: positive (direct) signal-response relation (SRR), negative (inverse) SRR to increase task complexity, specific instruction for enhanced attention to maximize tracking precision ("strict" instruction), and specific instruction that tracking precision would not be evaluated ("relaxed" instruction). The trials with positive and negative SRR were performed three times each to study training effects.

Specific metabolic properties of rat oculorotatory extraocular muscles can be linked to their low force requirements.

Purpose: To gain insight into the metabolic pathways of oculorotatory extraocular muscle (EOM) fiber types at the cellular level to explain their high fatigue resistance, rapid contraction, and low force output.

Methods: In consecutive sections of adult rat EOMs, the cross-sectional area (CSA) was calculated, and the activities of succinate-dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPDH) were measured by quantitative histochemistry of different fiber types classified by the myofibrillar adenosine triphosphatase (mATPase) staining pattern.

Results: In the orbital regions, type 1 (fast) fibers were present, showing small CSA, medium SDH, and low GPDH activity.

Influence of a 902.4 MHz GSM signal on the human visual system: investigation of the discrimination threshold.

The proximity of a mobile phone to the human eye raises the question as to whether radiofrequency (RF) electromagnetic fields (EMF) affect the visual system. A basic characteristic of the human eye is its light sensitivity, making the visual discrimination threshold (VDThr) a suitable parameter for the investigation of potential effects of RF exposure on the eye. The VDThr was measured for 33 subjects under standardized conditions.

The geomagnetic field influences the sensitivity of our eyes.

Experiments involving the orientation of animals, especially birds, have shown that the visual system and geomagnetic field are linked. On the basis of these findings, we have addressed the question of whether there is an influence of the geomagnetic field on light-sensitivity of the visual system in man. Here we report on measurements of the photopic sensitivity of the human visual system for a 0.