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1.
1.  Most studies examining interactions between insectivorous bats and tympanate prey use the echolocation calls of aerially-feeding bats in their analyses. We examined the auditory responses of noctuid (Eurois astricta) and notodontid (Pheosia rimosa) moth to the echolocation call characteristics of a gleaning insectivorous bat, Myotis evotis.
2.  While gleaning, M. Evotis used short duration (mean ± SD = 0.66 ± 0.28 ms, Table 2), high frequency, FM calls (FM sweep = 80 – 37 kHz) of relatively low intensity (77.3 + 2.9, –4.2 dB SPL). Call peak frequency was 52.2 kHz with most of the energy above 50 kHz (Fig. 1).
3.  Echolocation was not required for prey detection or capture as calls were emitted during only 50% of hovers and 59% of attacks. When echolocation was used, bats ceased calling 324.7 (±200.4) ms before attacking (Fig. 2), probably using prey-generated sounds to locate fluttering moths. Mean call repetition rate during gleaning attacks was 21.7 (±15.5) calls/s and feeding buzzes were never recorded.
4.  Eurois astricta and P. rimosa are typical of most tympanate moths having ears with BFs between 20 and 40 kHz (Fig. 3); apparently tuned to the echolocation calls of aerially-feeding bats. The ears of both species respond poorly to the high frequency, short duration, faint stimuli representing the echolocation calls of gleaning M. evotis (Figs. 4–6).
5.  Our results demonstrate that tympanate moths, and potentially other nocturnal insects, are unable to detect the echolocation calls typical of gleaning bats and thus are particularly susceptible to predation.
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2.
1.  When tested with legphone stimulation at 5 and 16 kHz, two prothoracic low-frequency neurons', ON1 and L1 of Acheta domesticus females, receive mainly excitation from one side (soma-ipsilateral in ON1, soma-contralateral in L1) and inhibition from the opposite side as is described for other cricket species (Figs. 2,3). While thresholds at 5 kHz are similar in L1 and ON1, L1 receives 16 kHz excitation with a 15- 20 dB higher threshold (lower than in other cricket species) than ON1. Stimulation of L1 with lower intensity 16 kHz sound on the side of its major input results in a clear IPSP visible in dendritic recordings (Figs. 3,4). In L1 and ON1 the intensity response at 16 kHz rises steeper than that at 5 kHz.
2.  The most sensitive auditory low-frequency receptors recorded have similar thresholds as ON1 and L1 at 5 kHz. Responses of the most sensitive auditory high-frequency receptors recorded show an intensity dependence which is similar to that of ON1 at 16 k Hz (Fig. 1C).
3.  Results of two-tone experiments show a tuning of inhibition in ON1 and L1 which is similar to excitatory tuning of ON1 (Fig. 4), however with about 10 to 15 dB higher thresholds. In contrast, in Gryllus bimaculatus an exact match between ON1-excitation and ON1/AN1 inhibition has been described.
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3.
1.  Within the tonotopic organization of the inferior colliculus two frequency ranges are well represented: a frequency range within that of the echolocation signals from 50 to 100 kHz, and a frequency band below that of the echolocation sounds, from 10 to 35 kHz. The frequency range between these two bands, from about 40 to 50 kHz is distinctly underrepresented (Fig. 3B).
2.  Units with BFs in the lower frequency range (10–25 kHz) were most sensitive with thresholds of -5 to -11 dB SPL, and units with BFs within the frequency range of the echolocation signals had minimal thresholds around 0 dB SPL (Fig. 1).
3.  In the medial part of the rostral inferior colliculus units were encountered which preferentially or exclusively responded to noise stimuli. — Seven neurons were found which were only excited by human breathing noises and not by pure tones, frequency modulated signals or various noise bands. These neurons were considered as a subspeciality of the larger sample of noise-sensitive neurons. — The maximal auditory sensitivity in the frequency range below that of echolocation, and the conspicuous existence of noise and breathing-noise sensitive units in the inferior colliculus are discussed in context with the foraging behavior of vampire bats.
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4.
We have identified a nerve carrying auditory afferents and characterized their physiological responses in the tiger beetle,Cicindela marutha.
1.  The tympana are located at the lateral margins of the first abdominal tergum. The nerve carrying the tympanal afferents is a branch of the dorsal root from the first abdominal ganglion.
2.  Both male and female auditory afferent responses are sharply tuned to 30 kHz with sensitivities of 50–55 dB SPL.
3.  The auditory afferents show little adaptation and accurately code the temporal characteristics of the stimulus with the limit of a resolution of 6–10 ms.
4.  The difference in threshold between contralateral and ipsilateral afferents for lateral stimuli is greatest at 30 kHz and is at least 10–15 dB.
5.  Ablation studies indicate that the floppy membrane in the anterolateral corner of the tympanum is crucial for transduction while the medial portion of the tympanum is less important.
6.  The tiger beetle and acridid (locust and grasshopper) ears have evolved independently from homologous peripheral structures. The neural precursor of the tympanal organs in both animals is likely the pleural chordotonal organ of the first abdominal segment.
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5.
1.  We tested the long-standing hypothesis that female frogs are attracted to the sound of a chorus of conspecific males from a distance. We studied the barking treefrog (Hyla gratiosa) because the location of choruses is unpredictable; thus, chorus sound indicates the presence of conspecific males as well as the location of a suitable breeding site.
2.  We measured the sound pressure level (SPL in dB re 20 Pa) in the 500 Hz octave band at various distances from choruses. The primary spectral peak in the advertisement call of this species is 400–500 Hz.
3.  The pattern of chorus sound attenuation in the 500 Hz band at two different sites was very similar and generally followed the pattern expected from geometrical spreading from a point source (Fig. 3). At one of the sites the SPL measured near ground level was always higher than that at a point 1 m above the ground (Fig. 3).
4.  Spectral analyses of the chorus sound at different distances showed that the low-frequency spectral peak in the range of 400–500 Hz was a prominent component, especially at 80–160 m (Figs. 1, 4). Amplitude peaks that corresponded to individual calls ofH. gratiosa and other species were also evident in oscillograms of recordings made at 160 m (Fig. 1).
5.  Gravid females oriented and moved toward a source of conspecific chorus sounds (originally recorded at 160 m from the pond) played back at 38–40 dB SPL in the 500 Hz octave band (Fig. 1, Table 1). Background noise levels were 43–47 dB SPL (C-weighted) and 24–25 dB SPL in the 500 Hz octave band.
6.  In a two-stimulus, choice experiment, females ofH. gratiosa always chose the source of a mixed chorus (H. gratiosa andH. cinerea) sound with conspecific males to a source of a pure chorus sound ofH. cinerea (Fig. 2, Table 2).
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6.
1.  Certain species of tiger moths emit clicks when stimulated by bat-like sounds. These clicks are generated by modified thoracic episterna (tymbals) (Fig. 1) and constitute a rhythmic behaviour activated by simple sensory input.
2.  Tymbal periods are indirectly related to stimulus intensity and periods (Fig. 3). Moths initiate sounds with the tymbal opposite to the stimulated ear and once a sequence commences it continues in an undisrupted fashion.
3.  The tymbal is innervated by a pleural branch (IIIN2a) of the metathoracic leg nerve, a similar anatomy to that in the unmodified episterna of silent moths (Fig. 5). Backfills of the IIIN2a in Cycnia tenera reveal sensory fibres and a cluster of 5–9 motor neurons with densely overlying dendritic fields (Fig. 6).
4.  Extracellular recordings of the IIIN2a reveal a large impulse preceding each tymbal sound (Fig. 7). I suggest that this impulse results from the synchronous firing of 2–3 motor neurons and is the motor output of the tymbal central pattern generator (CPG). The spikes alternate (Figs. 9, 10) and are bilaterally co-related (Fig. 11) but with an phase asymmetry of 2–3 ms (Fig. 12).
5.  Normal motor output continues in the absence of tymbal sounds (Fig. 13) and when all nerve-tymbal connections are severed (Fig. 14, Table 1) therefore this CPG operates independent of sensory feedback. A model is proposed for the tymbal circuitry based upon the present data and the auditory organization of related noctuid moths (Fig. 15). I propose that the tymbal response in modern arctiids evolved from either flight or walking CPGs and that preadaptive circuitry ancestral to tymbal movements still exists in modern silent Lepidoptera.
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7.
1.  The reactions of tympanic nerve fibers ofLocusta migratoria were recorded by glass microelectrodes in the metathoracic ganglion.
2.  The units were classified by frequency-, intensity-, and directional characteristics as well as by their response pattern. The response to speciesspecific song is compared with the response to song ofEphippiger ephippiger.
3.  The physiological properties lead to a classification into three types of low-frequency neurons (characteristic frequency 3.5–4 kHz; 4kHz; 5.5–6 kHz) and one type of high-frequency neuron (12–20 kHz). This is similar to other species (Gray, 1960, Michelsen, 1971).
4.  Intensity-coding is done by sharp rising intensity characteristics and by different absolute thresholds of the units.
5.  There is a marked directional sensitivity with some differences between LF and HF units. In the low frequency range the tympanal organ seems to react as a pressure gradient receiver; for high frequencies another mechanism is discussed.
6.  No filtering of species-specific song takes place at the level of the receptor cells.
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8.
1.  Bees were trained to enter the central hole in a disc containing 89 holes and collect sugar-water from a box placed behind it (Fig. 1). Visual marks were offered on the inner surface of a cylinder placed in front of the disc (Fig. 2), thus projecting onto peripheral (nonfrontal) regions of the bees' eye. The trained bees were tested by recording their choices among the holes.
2.  Bees use the memorized position of peripheral marks to localize the frontally positioned goal (Figs. 6–9). The effectiveness of a mark depends on its retinal position, the most effective marks being lateral ones (Figs. 8, 9).
3.  Altering the dimensions of the mark does not influence the distribution of the bees' choice (Figs. 11–13). Thus, image motion rather than image size is used for distance estimation in the present task.
4.  Cinematographic recordings (Fig. 14) revealed that the searching bees' whereabouts are correlated with the choice distribution (Fig. 6a). The hypothesis that the bees stabilize the mark in the trained retinal position by correcting for retinal image slip is proposed.
5.  Experiments using coloured patterns revealed that the bees' performance is mediated by the green-sensitive channel (Figs. 17–22), as predicted by the above hypothesis.
Dedicated to Prof. Dr. Rüdiger Wehner on the occasion of his 50th birthday, in great appreciation for both his scientific work and his personality.  相似文献   

9.
1.  The activity of tympanal high- and low-frequency receptors in the migratory locustLocusta migratoria was recorded with glass capillary microelectrodes, and Lucifer Yellow was then injected through the microelectrode to reveal the cells' metathoracic projections.
2.  A photodetector device was used to monitor the abdominal respiratory movements, which caused clearly visible deflections of the tympanal membrane.
3.  The auditory receptors respond not only to sound stimuli but also to the respiratory movements; these phasic (Figs. 1–3) or tonic (Fig. 4) responses are especially pronounced during the inspiration and expiration movements, and less so during the constriction phases.
4.  The magnitude of the response to sound depends on the phase of the stimulus with respect to the respiratory movements. At certain phases sound elicits no response at all (Fig. 5).
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10.
Juvenile and young adult specimens ofCarcinus maenas were kept in the laboratory under controlled conditions. The main organic constituents and their variations during the molt cycle were quantitatively determined.
1.  During postmolt the chitin concentration rises rapidly (20–74 mg/g dry weight) in parallel to the dry weight (120–293 mg/g fresh weight). Both decrease again before ecdysis (Fig. 1).
2.  The glycose level in the hemolymph (50–80 g/ml) shows no significant variation during the molt cycle (Fig. 2).
3.  The glycogen concentrations in integument, (14–180 mg/g dry weight), gills (5.5–66 mg/g dry weight), muscle (8.8–41 mg/g dry weight), heart (135–308 mg/g dry weight) and hemolymph (160–690 g/ml) reach their maximum values during the premolt stage. The highest glycogen content in the midgut gland (83 mg/g dry weight) is observed immediately before and after ecdysis. Glycogen storage in heart and hemolymph, can, account for about half of the glycogen stored in the midgut gland (Figs. 3,4 and 5).
4.  The lipid concentration in the hemolymph (120–440 g/ml) and in gills (33.6–70 mg/g dry weight) rises during the premolt stage (Figs. 6 and 7).
5.  The protein concentration in the hemolymph increased during premolt (9–31 mg/ml). The copper content (13–42 g/ml) varies in parallel to the protein concentration indicating that the proportion of hemocyanin to total proteins remains constant during the molting cycle (Fig. 8).
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11.
Locusts (Locusta migratoria) were flown in a flight simulator which converts yaw torque into angular motion of the visual environment (Fig. 1). The modalities and the time-course of steering behavior under these closed-loop conditions have been investigated.
1.  Locusts flying under visual closed-loop conditions stabilize their visual environment by performing correctional steering manoeuvres. Besides torque production, due to differential wing movements and ruddering, correctional steering also involves head movements (Fig. 6).
2.  During open-loop steering, ruddering and yaw torque begin some 60 ms after the onset of the visually simulated deviation from course. Head movements occur some 90 ms after stimulus onset, i.e. some 30 ms later than yaw torque (Figs. 3, 5) and therefore do not initiate thoracic steering outputs.
3.  Open- and closed-loop correctional steering do not differ in their behavioral components or temporal organization (Figs. 2, 6, Table 1).
4.  In the absence of major disturbances, correctional steering under closed-loop conditions is performed with minimal ruddering (only a few degrees in amplitude), that probably produces little or no aerodynamic drag (Fig. 6).
5.  Locusts prevented from moving their heads still stabilize their visual environment in the closed-loop situation. However, the precision of steering is affected by this constraint (Figs. 8, 9, 10, 12). Head immobilization also alters the temporal coordination of correctional steering (Figs. 7, 11).
6.  These results show that head movements, in addition to their generally accepted role in vision improvement, also contribute to the precision and temporal coordination of correctional flight manoeuvres. The mechanism is partly via proprioceptive feedback.
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12.
In response female pheromone the male gypsy moth flies a zigzagging path upwind to locate the source of odor. He determines wind direction visually. To learn more about the mechanism underlying this behavior, we studied descending interneurons with dye-filled micro-electrodes. We studied the interneuronal responses to combinations of pheromone and visual stimuli.
1.  We recorded 5 neurons whose directionally selective visual responses to wide field pattern movement were amplified by pheromone (Figs. 2–6).
2.  The activity of the above neurons was more closely correlated with the position of the moving pattern than with its velocity (Fig. 4).
3.  One neuron showed no clearly directional visual response and no response to pheromone. Yet in the presence of pheromone it showed directionally selective visual responses (Fig. 6).
4.  We recorded 4 neurons whose directionally selective visual responses were not modulated by pheromone (Fig. 7), ruling out the possibility that the effect of the pheromone was simply to raise the activity of all visual neurons.
5.  Our results suggest that female pheromone amplifies some neural pathways mediating male optomotor responses, especially the directionally selective responses to the transverse movement of the image, both below and above the animal.
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13.
1.  The cochlea of the horseshoe bat,Rhinolophus ferrumequinum, was frequency mapped by exposing for 30 min to one or two continuous pure tones of intensities between 70 and 110 dB SPL. The evaluation was made by differentiating between normal and swollen nuclei of the outer hair cells (OHC) of the organ of Corti and by measuring the diameter of the nuclei of the OHC.
2.  In control animals the radial diameter of the OHC nuclei varies systematically from a mean of 2.85 m at the base to 3.2 um at the apex (Fig. 1).
3.  All frequencies used for exposure were normalized to the resting frequency (FR), which is the frequency of the pure tone component of the orientation sound in a non-flying bat. The individual FR lay between 82.6 and 83.3 kHz.
4.  For analysing the small frequencies between 83.0 to 86.0 kHz in which relevant echoes occur, 3.15 mm length of the basilar membrane is used, about the same length as for the octaves from FR/4 to FR/2 (2.85 mm) and from FR/2 to FR (3.2 mm) (Fig. Ca, b).
5.  The discontinuity of the mechanical data at 4.5 mm of the length of the basilar membrane (part I of this paper) coincides with FR and the less pronounced discontinuity at 7.8 mm coincides with FR/2.
6.  Location and mechanism of the auditory filter are discussed.
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14.
1.  Echolocating bats use the time delay between emitted sounds and returning echoes to determine the distance to an object. This study examined the accuracy of target ranging by bats and the effect of echo bandwidth on the bat's performance in a ranging task.
2.  Six big brown bats (Eptesicus fuscus) were trained in a yes-no procedure to discriminate between two phantom targets, one simulating a stationary target that reflected echoes at a fixed delay and another simulating a jittering target that reflected echoes undergoing small step-changes in delay.
3.  Eptesicus fuscus emits a frequency modulated sonar sound whose first harmonic sweeps from approximately 55 to 25 kHz in about 2 ms. Sound energy is also present in the second and third harmonics, contributing to a broadband signal in which each frequency in the sound can provide a time marker for its arrival at the bat's ears. We estimated range jitter discrimination in bats under conditions in which the echo information available to the bat was manipulated. Baseline performance with unfiltered echoes was compared to that with filtered echoes (low-pass filtered at 55 kHz and at 40 kHz; high-pass filtered at 40 kHz).
4.  The results indicate that the low-frequency portion of the first harmonic (25–40 kHz) is sufficient for the bat to discriminate echo delay changes of 0.4 microseconds. This echo delay discrimination corresponds to a distance discrimination of less than 0.07 mm.
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15.
1.  Up to 9 kHz, the tympanal membrane of the grasshopper Chorthippus biguttulus responds with equal sensitivity at the attachment sites of the low and the high-frequency receptors; at the latter site it is also particularly sensitive between 10 and 20 kHz.
2.  The frequency spectra of the songs of both sexes exhibit maxima at 7–8 kHz, to which the membrane is well matched. In the high-frequency region, where the male songs have a peak at 30 kHz, there is no corresponding maximum in the membrane oscillation.
3.  Because the tympanal membrane is immediately adjacent to air sacs in the tracheal system, it is deflected inward and outward by as much as 80 m during the respiratory cycle.
4.  Measurements by laser vibrometry show that acoustically induced membrane oscillations are attenuated severely due to the respiratory displacement of the membrane for frequencies up to 10–12 kHz. By contrast, at higher frequencies the membrane sensitivity is doubled or tripled.
5.  As a result of these membrane effects, the discharge in the tympanal nerve was profoundly reduced in the low-frequency range, whereas above 11 kHz there was a marked increase. This modulation of auditory sensitivity affects the animals' ability to detect conspecific songs.
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16.
1.  By penetrating axons in the ventral nerve cord of the dragonfly, Aeshna umbrosa, we measured the intracellular responses of target-selective visual interneurons to movement of black square targets ranging from 1° to 32° visual angle at several levels of mean background luminance.
2.  Neuronal responses, measured both in number of spikes and in the magnitude of integrated postsynaptic potentials, showed a preference for larger target size at lower mean luminance (Table 1, Figs. 1–3). The latency of postsynaptic potential (psp) and spike responses from onset of target movement increased with a decrease in mean luminance (Fig. 1).
3.  A measure of mean target size preference (Eqn. 1) for one identified interneuron (MDT4) in both laboratory and outdoor lighting shows a continuous decrease of preferred size with increases of mean luminance over more than 4 orders of magnitude.
4.  The time to reach the new steady state of cell response after the decrease of mean luminance was ordinarily less than 30 s, but sometimes longer (Fig. 4).
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17.
In the grasshopperChorthippus biguttulus the stridulatory movements of males with surgically manipulated ventral nerve cords were investigated.
1.  The stridulation pattern of animals with a hemisected mesothoracic ganglion was indistinguishable from that of intact animals.
2.  After hemisection of the metathoracic ganglion several animals were still able to stridulate in the species-specific pattern (Figs. 3, 5). Different structural elements of the song, however, were affected to different degrees by this operation. Although the stereotyped up-and-down movements were normal, the rhythm of pauses, which in intact animals are inserted after every third to fourth up- and-down cycle, was disturbed. As a result, the variation of syllable lengths was much higher (Fig. 4).
3.  A prominent feature after hemisection of the metathoracic ganglion was an almost complete loss of coordination between left and right hind legs (Figs. 5–7). Only in the coarse structure of the song (e.g. the beginning and termination of song sequences) was a correlation of the leg movements still discernible. This was especially obvious in songs of the rivalry type and in precopulatory kicking movements (Fig. 8).
4.  If in addition to hemisection of the metathoracic ganglion one of the neck connectives was transected the animals stridulated only with the hind leg ipsilateral to the intact connective (Fig. 11).
5.  Even after hemisection of both the meso- and metathoracic ganglia, animals were able to produce the species-specific stridulation pattern (Fig. 9).
6.  In animals with hemisected metathoracic ganglia and both connectives between pro- and mesothoracic ganglia transected, components of the species-specific pattern could be induced by current injection into the mesothoracic ganglion (Fig. 10).
7.  These results suggest that the stridulation rhythm-producing neuronal network is composed of hemisegmental subunits. A hemiganglionic structure of rhythm generators might reflect the ancestral organization of locomotion-controlling networks.
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18.
1.  The relationships between fatigue, heart rate, lactate accumulation, and hemolymph pressure during and after maximal activity were investigated in three spider species (Filistata hibernalis, Lycosa lenta, andPhidippus audax), characterized by different life histories and physiologies (Table 1).
2.  In the initial 20 s of a forced two min run, spiders cover up to 50% the total distance of the entire run, lose 2/3rds of their initial speed, and change gait. The remainder of the activity bout is marked by a gradual slowing and increased incidence of individuals that refuse to move.
3.  Maximal heart rates are reached late in the two min activity bout, or more commonly, early in recovery (Fig. 2).
4.  Prosomal lactate accumulations similar to levels associated with fatigue in many terrestrial ectothermic vertebrates are reached after about 1 min of forced activity (Fig. 3). However, lactate accumulations inLycosa during the first 20 sec of activity (Fig. 4) were less than 1/3rd the level found at 2 min and were probably not high enough to explain the rapid fatigue that occurs during early activity (Fig. 1).
5.  Hemolymph pressures were measured in maximally activeFilistata that were restrained in a manner designed to reduce the work load on locomotory muscles. Hemolymph pressures increased rapidly to 100–200 mmHg with the onset of activity but peak pressures of 450 mmHg were not reached until after 20 s (Fig. 5). Alternative forms of stimulation did not result in earlier peak pressures. High pressures (>120 mmHg) continued for most of the 2-min activity period. Lactate accumulation during this exercise was much less than in forced running.
6.  The ability of restrained spiders to maintain high hemolymph pressures and continue rapid leg extensions mimicking running and jumping for an extended period of time is contrary to the hydraulic insufficiency hypothesis' explanation of rapid fatigue. The cause of the ultimate locomotory collapse (seen after 1–4 min) is probably related to the accumulation of anaerobic by-products.
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19.
Intracellular recordings have been made of responses to step, ramp and sinusoidal changes of light by second-order L-neurones and a third-order neurone, DNI, of locust (Locusta migratoria) ocelli.
1.  The membrane potential at the peak response by an L-neurone to a change in light is proportional to the light increment or decrement, independent of background, over a range of at least 4 log units. As background increases, response latency and time-course decrease, and responses become more phasic (Fig. 1).
2.  Adaptation to a changed mean light level involves a change in sensitivity and a slow change in resting membrane potential, which never adapts completely to dark resting potential in the presence of light (Fig. 3).
3.  L-neurones can follow changes in light which last several seconds, but responses to fast changes are enhanced in amplitude (Figs. 4, 5). An increase in background light causes an increase in the frequency of sinusoidally modulated light at which the largest response occurs (Fig. 4).
4.  The responses of DNI to increased light saturate at lower intensities than those of L-neurones. During adaptation to different background light intensities, there is no change in the input-output relation of the synapse between an L-neurone and DNI (Figs. 6, 7).
5.  For a rapid decrease in light, DNI produces a rebound spike, followed by a period of silence (Figs. 5, 8).
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20.
1.  The diffusive hydrogen conductance of chicken eggshell compound membrane was measured in situ on day 16 of incubation, in a direction parallel to the shell and the chorioallantois (lateral conductance). A value of 3.9 mmol d–1 kPa–1 was obtained through a ring 13.29 cm in circumference, 0.0076 cm thick and 0.3 cm long.
2.  Lateral hydrogen conductance for 1 mm2 of shell membrane 76 m thick is 30 times the conductance of one pore serving the same area.
3.  Lateral conductance for H2 is not significantly influenced by chorioallantoic perfusion.
4.  Oxygen consumption change due to partial covering of the hen eggshell indicates that there is a significant resistance to lateral diffusion of oxygen under the shell toward the covered area.
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