The Eye Muscle of Calliphora Vomitoria L

1973 ◽  
Vol 58 (3) ◽  
pp. 585-598
Author(s):  
JOHN PATTERSON
Keyword(s):  
Dark Adaptation ◽  
Interspike Interval ◽  
Compound Eye ◽  
Response Threshold ◽  
Interspike Intervals ◽  
Muscle System ◽  
Eye Muscle ◽  
High Stimulus ◽  
Resting Activity ◽  
Effect Of Light

1. Changes in the intensity of the illumination falling on the compound eye produce transient changes in the interspike interval of the tonic potentials generated by the eye muscle of Calliphora vomitoria. These changes are distinct and frequently different in direction from changes in resting activity produced by light and dark adaptation which have been described previously. 2. The effect of ‘light-on’ at high stimulus intensities is to produce a transient increase in the interspike intervals of the eye-muscle potentials. At lower intensities the result is a transient decrease in the interspike intervals. 3. ‘Light-off’ consistently evokes a decrease in the interspike interval, and the magnitude of the decrease is graded with the logarithm of the preceding light intensity. 4. With high-intensity stimuli changes in the interspike intervals occur within 200 msec of a change in illumination and continue to develop for at least 2 sec. The interspike intervals have returned to near to the pre-stimulus values within 30 sec to 2 min of the onset of the stimulus. 5. The behaviour of the eye-muscle system is described for ‘near-threshold’ stimuli and response ‘threshold’ is found to vary with adapting intensity in a way which illustrates a Weber-Fechner relationship.

scholarly journals The Eye Muscle of Calliphora Vomitoria L

1973 ◽  
Vol 58 (3) ◽  
pp. 565-583
Author(s):  
JOHN PATTERSON
Keyword(s):  
Dark Adaptation ◽  
Light Adaptation ◽  
Interspike Interval ◽  
Compound Eye ◽  
Optic Lobe ◽  
Visual Images ◽  
Eye Muscle ◽  
Calliphora Erythrocephala ◽  
Spontaneous Movements ◽  
Anatomical Arrangement

1. A muscle attached to the medial edge of the compound eye is described for the blowfly Calliphora vomitoria. 2. Electrophysiological activity in the form of continuous tonically firing potentials can be recorded extracellularly from the muscle. These potentials are generated by the muscle and have the same origin as the ‘clock-spikes’ recorded previously from the optic lobe of Calliphora erythrocephala. 3. The interspike interval of the eye muscle potentials varies inversely with the ambient temperature. 4. Light-adaptation results in a decrease and dark-adaptation an increase in the resting interspike interval of the eye-muscle potentials. 5. Light-adaptation is correlated with increase and dark-adaptation with decrease in the depth of the compound eye as measured at the insertion of the muscle. 6. The pseudopupil produced by illumination of the compound eye from the inside displays spontaneous movements which can be correlated with the anatomical arrangement and spontaneous activity of the eye muscle. 7. The probable function of spontaneous and transient changes in eye-muscle activity is to promote scanning of the visual images produced by the dioptrics of the compound eye.

Effect of light and dark adaptation upon the rhabdom in the compound eye of the mosquito

1978 ◽  
Vol 206 (2) ◽  
pp. 151-156 ◽  
Author(s):  
J. D. Brammer ◽  
Peter J. Stein ◽  
Ronald A. Anderson
Keyword(s):  
Dark Adaptation ◽  
Compound Eye ◽  
Effect Of Light

Changes of Acuity during Light and Dark Adaptation in the Dragonfly Compound Eye

1990 ◽  
Vol 45 (1-2) ◽  
pp. 137-142 ◽  
Author(s):  
Eric J. Warrant ◽  
Robert B. Pinter
Keyword(s):  
Dark Adaptation ◽  
Time Course ◽  
Light Adaptation ◽  
Compound Eye ◽  
Sensitivity Function ◽  
The State ◽  
Intracellular Recordings ◽  
Acceptance Angle ◽  
Angular Sensitivity ◽  
Rapid Reduction

Abstract Intracellular recordings of angular sensitivity from the photoreceptors of Aeschnid dragonflies (Hemianax papuensis and Aeschna brevistyla) are used to determine the magnitude and time course of acuity changes following alterations of the state of light or dark adaptation. Acuity is defined on the basis of the acceptance angle, Δρ (the half-width of the angular-sensitivity function). The maximally light-adapted value of Δρ is half the dark-adapted value, indicating greater acuity during light adaptation. Following a change from light to dark adaptation, Δρ increases slowly, requiring at least 3 min to reach its dark-adapted value. In contrast, the reverse change (dark to light) induces a rapid reduction of Δρ , and at maximal adapting luminances, this reduction takes place in less than 10 sec.

Period-Adding Bifurcation with Chaos in the Interspike Intervals Generated by an Experimental Neural Pacemaker

1997 ◽  
Vol 07 (08) ◽  
pp. 1867-1872 ◽  
Author(s):  
W. Ren ◽  
S. J. Hu ◽  
B. J. Zhang ◽  
F. Z. Wang ◽  
Y. F. Gong ◽  
...  
Keyword(s):  
Neural Coding ◽  
Calcium Concentration ◽  
Channel Blocker ◽  
Interspike Interval ◽  
Surrogate Data ◽  
Nonlinear Phenomena ◽  
Chaotic Oscillations ◽  
Interspike Intervals ◽  
Excitable Cells ◽  
Nonlinear Forecasting

The dynamics of the generation of the various spike trains in neural pacemakers is of fundamental importance to the understanding of neural coding. Recent studies have demonstrated, theoretically and experimentally, that neural pacemakers produce chaotic oscillations. Deeper analyses in several neuronal models have revealed many nonlinear phenomena including period-adding bifurcations whose existence has not been experimentally confirmed. In this letter, we reported that the period-adding bifurcation with chaos was observed in the interspike interval (ISI) series generated by an experimental neural pacemaker when the extracellular calcium concentration was changed or a potassium channel blocker was administered at the site of the pacemaker. We also simulated our experimental discoveries by computing a generalized model of excitable cells. The chaotic phenomenon in the experiment and that in the model were demonstrated and compared using the nonlinear forecasting and surrogate data methods.

Adaptation in the Compound Eye and Interaction with Screening Pigment

1972 ◽  
Vol 56 (1) ◽  
pp. 119-128
Author(s):  
U. YINON
Keyword(s):  
Dark Adaptation ◽  
Light Adaptation ◽  
Compound Eye ◽  
Electrical Response ◽  
Negative Potential ◽  
Neural Pathways ◽  
Photochemical Process ◽  
Screening Pigment ◽  
The Difference ◽  
Adaptation Processes

The electroretinogram pattern in the compound eye of T. molitor and the appearance of irregular small potentials and spikes superimposed on the ERG are influenced during dark and light adaptation procedures. The amplitude of the principal negative potential reflects bleaching and recovery of the photochemical process. This is not true for the latency values. The delay of the electrical response increases in the dark and decreases in the light adapted eye. These changes were influenced by the intensity of the adapting light. Mutant eyes only lack screening pigment and have normal visual neural pathways. The absence of this pigment lowered the threshold sensitivity of the unscreened eye in dark adaptation. The difference between the adaptation processes in mutants and normal animals has been suggested as a criterion for measuring the net effect of the screening pigment in the compound eye.

Mechanosensitive Properties of Gastric Vagal Afferent Fibers in the Rat

1999 ◽  
Vol 82 (5) ◽  
pp. 2210-2220 ◽  
Author(s):  
Noriyuki Ozaki ◽  
J. N. Sengupta ◽  
G. F. Gebhart
Keyword(s):  
Acute Inflammation ◽  
Platelet Activating Factor ◽  
Response Threshold ◽  
Gastric Distension ◽  
Intragastric Pressure ◽  
Afferent Fibers ◽  
Slow Adaptation ◽  
Resting Activity ◽  
Response Thresholds ◽  
Vagal Afferent

Single, teased fiber recordings were made from the decentralized right cervical vagus nerve (hyponodal) of the rat. A total of 67 afferent fibers that responded to gastric distension (GD) were studied: 9 fibers were stimulated by phasic balloon GD, 58 by more natural fluid GD. All balloon GD–responsive fibers had resting activity (3.1 imp/s), and 57/58 fluid GD responsive fibers had resting activity (1.3 imp/s). All balloon GD–responsive fibers exhibited a dynamic response to phasic distension followed by slow adaptation, whereas fluid GD–responsive fibers exhibited increasing responses as intragastric pressure increased, followed typically by slow adaptation. Responses to graded GD were studied in all fibers, and all gave increasing responses to increasing pressures (5–60 mmHg). Thresholds for response varied between 0 and 18 mmHg. Mean response thresholds for two durations of fluid GD (30 and 60 s) were 5.6 and 3.9 mmHg; the mean response threshold to phasic balloon GD (30 s duration) was 5.3 mmHg. The potential sensitizing effect of platelet activating factor (PAF, 50 or 100 ng · kg−1 · min−1 for 20 min) infused into the gastric artery was studied in 20 fibers. Fifteen fibers exhibited an increase in spontaneous activity; intragastric pressure also slightly increased during PAF infusion. The increase in activity produced by PAF was attenuated in the presence of the PAF receptor antagonist WEB 2086. After PAF-induced acute inflammation of the stomach, three of five fibers studied did not exhibit any change in response to graded GD. The present study characterized distension-sensitive afferent fibers in the right cervical vagus innervating the stomach of the rat by balloon GD and fluid GD. The results document that all distension-sensitive gastric vagal afferent fibers encoded the intensity of GD, but none had response thresholds in what might be considered the noxious range. PAF infusion activated mechanosensitive gastric vagal afferent fibers, but acute inflammation produced by PAF did not sensitize responses to GD.

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