共查询到20条相似文献,搜索用时 15 毫秒
1.
Alexander V. Galazyuk Albert S. Feng 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(4):301-311
Responses of 117 single- or multi-units in the auditory cortex (AC) of bats (Myotis lucifugus) to tone bursts of different stimulus durations (1– 400 ms) were studied over a wide range of stimulus intensities to determine
how stimulus duration is represented in the AC. 36% of AC neurons responded more strongly to short stimulus durations showing
short-pass duration response functions, 31% responded equally to all pulse durations (i.e., all-pass), 18% responded preferentially
to stimuli having longer durations (i.e., long-pass), and 15% responded to a narrow range of stimulus durations (i.e., band-pass).
Neurons showing long-pass and short-pass duration response functions were narrowly distributed within two horizontal slabs
of the cortex, over the rostrocaudal extent of the AC. The effects of stimulus level on duration selectivity were evaluated
for 17 AC neurons. For 65% of these units, an increase in stimulus intensity resulted in a progressive decrease in the best
duration. In light of the unusual intensity-dependent duration responses of AC neurons, we hypothesized that the response
selectivities of AC neurons is different from that in the brainstem. This hypothesis was validated by results of study of
the duration response characteristics of single neurons in the inferior colliculus.
Accepted: 8 November 1996 相似文献
2.
S. Haplea E. Covey J. H. Casseday 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1994,174(6):671-683
To determine the level at which certain response characteristics originate, we compared monaural auditory responses of neurons in ventral cochlear nucleus, nuclei of lateral lemniscus and inferior colliculus. Characteristics examined were sharpness of frequency tuning, latency variability for individual neurons and range of latencies across neurons.Exceptionally broad tuning curves were found in the nuclei of the lateral lemniscus, while exceptionally narrow tuning curves were found in the inferior colliculus. Neither specialized tuning characteristic was found in the ventral cochlear nuclei.All neurons in the columnar division of the ventral nucleus of the lateral lemniscus maintained low variability of latency over a broad range of stimulus conditions. Some neurons in the cochlear nucleus (12%) and some in the inferior colliculus (15%) had low variability in latency but only at best frequency.Range of latencies across neurons was small in the ventral cochlear nucleus (1.3–5.7 ms), intermediate in the nuclei of the lateral lemniscus (1.7–19.8 ms) and greatest in the inferior colliculus (2.9–42.0 ms).We conclude that, in the nuclei of the lateral lemniscus and in the inferior colliculus, unique tuning and timing properties are built up from ascending inputs.Abbreviations AVCN
anteroventral cochlear nucleus
- BF
best frequency
- CV
coefficient of variation
- DCN
dorsal cochlear nucleus
- FM
frequency modulation
- IC
inferior colliculus
- NLL
nuclei of lateral lemniscus
- PSTH
post stimulus time histogram
- PVCN
posteroventral cochlear nucleus
- SD
standard deviation
- SPL
sound pressure level
- VCN
ventral cochlear nuclei
- VNLLc
ventral nucleus of the lateral lemniscus, columnar division 相似文献
3.
M. J. Ferragamo T. Haresign J. A. Simmons 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,182(1):65-79
Neurons in the inferior colliculus (IC) of the awake big brown bat, Eptesicus fuscus, were examined for joint frequency and latency response properties which could register the timing of the bat's frequency-modulated (FM) biosonar echoes. Best frequencies (BFs) range from 10 kHz to 100 kHz with 50% tuning widths mostly
from 1 kHz to 8 kHz. Neurons respond with one discharge per 2-ms tone burst or FM stimulus at a characteristic latency in
the range of 3–45 ms, with latency variability (SD) of 50 μs to 4–6 ms or more. BF distribution is related to biosonar signal
structure. As observed previously, on a linear frequency scale BFs appear biased to lower frequencies, with 20–40 kHz overrepresented.
However, on a hyperbolic frequency (linear period) scale BFs appear more uniformly distributed, with little overrepresentation.
The cumulative proportion of BFs in FM1 and FM2 bands reconstructs a scaled version of the spectrogram of FM broadcasts. Correcting FM latencies for absolute BF latencies
and BF time-in-sweep reveals a subset of IC cells which respond dynamically to the timing of their BFs in FM sweeps. Behaviorally,
Eptesicus perceives echo delay and phase with microsecond or even submicrosecond accuracy and resolution, but even with use of phase-locked
FM and tone-burst stimuli the cell-by-cell precision of IC time-frequency registration seems inadequate by itself to account
for the temporal acuity exhibited by the bat.
Accepted: 21 June 1997 相似文献
4.
S. R. Soffe 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(6):711-715
Young Xenopus tadpoles were used to test whether the pattern of discharge in specific sensory neurons can determine the motor response
of a whole animal. Young Xenopus tadpoles show two main rhythmic behaviours: swimming and struggling. Touch-sensitive skin sensory neurons in the spinal cord
of immobilised tadpoles were penetrated singly or in pairs using microelectrodes to allow precise control of their firing
patterns. A single impulse in one Rohon-Beard neuron (= light touch) could sometimes trigger “fictive” swimming. Two to six
impulses at 30–50 Hz (= a light stroke) reliably triggered fictive swimming. Neither stimulus evoked fictive struggling. Twenty-five
or more impulses at 30–50 Hz (= pressure) could evoke a pattern of rhythmic bursts, distinct from swimming and suitable to
drive slower, stronger movements. This pattern showed some or all the characteristics of “fictive” struggling. These results
demonstrate clearly that sensory neurons can determine the pattern of motor output simply by their pattern of discharge. This
provides a simple form of behavioural selection according to stimulus.
Accepted: 28 November 1996 相似文献
5.
John D. Crawford 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(5):439-450
The mormyrid fish Pollimyrus adspersus has auditory specializations for sound pressure detection and uses acoustic displays in its natural social behavior. In this
paper it is shown that auditory neurons in the mesencephalon (torus semicircularis) are activated selectively by temporal
features of complex sounds. Single neurons were recorded while presenting sounds to fish underwater. The stimuli were acoustic
click trains, 400 ms in duration, and were synthesized with differing inter-click-intervals (ICIs). The natural sounds of
this species are composed similarly and the range of ICIs synthesized overlapped with the natural range (5–40 ms). One-third
of the neurons studied were strongly selective for a narrow range of ICIs, increasing spike rate by ten fold or more at the
best ICI compared to the minimum response observed. The best ICI for interval selective neurons remained stable when the sound
pressure of the stimulus was changed. Neurons that were selective gave phasic responses to tone bursts, and most had non-monotonic
rate level functions. The origin of interval selectivity is discussed and a time-based computational mechanism is proposed.
Accepted: 20 December 1996 相似文献
6.
S. Credner H. Burda F. Ludescher 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(3):245-255
In captive adult Zambian mole-rats 14 different sounds (13 true vocalizations) have been recorded during different behavioural
contexts. The sound analysis revealed that all sounds occurred in a low and middle frequency range with main energy below
10 kHz. The majority of calls contained components of 1.6–2 kHz, 0.63–0.8 kHz, and/or 5–6.3 kHz. The vocalization range thus
matched well the hearing range as established in other studies. The frequency content of courtship calls in two species of
Zambian Cryptomys was compared with that in naked mole-rats (Heterocephalus glaber) and blind mole-rats (Spalax ehrenbergi) as described in the literature. The frequency range of maximum sound energy is negatively correlated with the body weight
and coincides with the frequencies of best hearing in the respective species. In general, the vocalization range in subterranean
mammals is shifted towards low frequencies which are best propagated in underground burrows.
Accepted: 16 September 1996 相似文献
7.
Xinming Wang Alexander V. Galazyuk Albert S. Feng 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(1):13-20
Previous studies in echolocating bats, Myotis lucifugus, showed that paradoxical latency shift (PLS) is essential for neural computation of target range and that a number of neurons
in the inferior colliculus (IC) exhibit unit-specific PLS (characterized by longer first-spike latency at higher sound levels)
in response to tone pulses at the unit’s best frequency. The present study investigated whether or not frequency-modulated
(FM) pulses that mimic the bat’s echolocation sonar signals were equally effective in eliciting PLS. For two-thirds of PLS
neurons in the IC, both FM and tone pulses could elicit PLS, but only FM pulses consistently produced unit-specific PLS. For
the remainder of PLS neurons, only FM pulses effectively elicited PLS; these cells showed either no PLS or no response, to
tone pulses. PLS neurons generally showed more pronounced PLS in response to narrow-band FM (each sweeping 20 kHz in 2 ms)
pulse that contained the unit’s best frequency. In addition, almost all PLS neurons showed duration-independent PLS to FM
pulses, but the same units exhibited duration-dependent PLS to tone pulses. Taken together, when compared to tone pulses,
FM stimuli can provide more reliable estimates of target range. 相似文献
8.
DeForest Mellon Jr. 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(5):553-565
The cellular substrates of antennular flicking behavior in the crayfish Procambarus clarkii were investigated. Flicking involves fast downward movements of the external filament of each biramous antennule (1st antenna),
and is mediated by phasic contractions of a short muscle, the external filament depressor. Phasic contractions of the external
filament depressor depend upon stereotyped impulse bursts in a single motorneuron (P1). These bursts have a characteristic
impulse frequency profile that is consistent upon successive occurrences. The temporal characteristics of the impulse burst
suggest that the central depolarizations generating each burst may be similar to driver potentials described for motor neurons
in crustacean cardiac ganglia. Responses of the external filament to odorants have a long latency and are characterized by
repetitive bursts and tonic activity in some external filament depressor fibers. Tonic activity in a slowly contracting muscle,
the antennular depressor muscle, is also evoked by chemical stimulation. Flicking is consistently evoked only by mechanical
or hydrodynamic stimulation of the cephalothorax, antennae and antennules. The sensitivity and short latency of the hydrodynamic
antennule-generated flick reflex is consistent with the sensitivity of rapidly conducting, hydrodynamically activated mechanoreceptor
neurons in both antennular filaments. I propose that antennular flicking, which has been shown to enhance the dynamic response
characteristics of olfactory receptor neurons on the external antennular filament, has evolved as a response to the turbulence
associated with fluid movement, within which chaotic odorant concentration fronts may be imbedded.
Accepted: 23 October 1996 相似文献
9.
Morten Buhl Jørgensen Jakob Christensen-Dalsgaard 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(5):503-511
We studied the directionality of spike timing in the responses of single auditory nerve fibers of the grass frog, Rana temporaria, to tone burst stimulation. Both the latency of the first spike after stimulus onset and the preferred firing phase during
the stimulus were studied. In addition, the directionality of the phase of eardrum vibrations was measured. The response latency
showed systematic and statistically significant changes with sound direction at both low and high frequencies. The latency
changes were correlated with response strength (spike rate) changes and were probably the result of directional changes in
effective stimulus intensity. Systematic changes in the preferred firing phase were seen in all fibers that showed phaselocking
(i.e., at frequencies below 500–700 Hz). The mean phase lead for stimulation from the contralateral side was approximately
140° at 200 Hz and decreased to approximately 100° at 700 Hz. These phaseshifts correspond to differences in spike timing
of approximately 2 ms and 0.4 ms respectively. The phaseshifts were nearly independent of stimulus intensity. The phase directionality
of eardrum vibrations was smaller than that of the nerve fibers. Hence, the strong directional phaseshifts shown by the nerve
fibers probably reflect the directional characteristics of extratympanic pathways.
Accepted: 23 November 1996 相似文献
10.
Julio C. Hechavarría Ariadna T. Cobo Yohami Fernández Silvio Macías Manfred Kössl Emanuel C. Mora 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(12):1159-1172
Frequency tuning, temporal response pattern and latency properties of inferior colliculus neurons were investigated in the
big fruit-eating bat, Artibeus jamaicensis. Neurons having best frequencies between 48–72 kHz and between 24–32 kHz are overrepresented. The inferior colliculus neurons
had either phasic (consisting in only one response cycle at all stimulus intensities) or long-lasting oscillatory responses
(consisting of multiple response cycles). Seventeen percent of neurons displayed paradoxical latency shift, i.e. their response
latency increased with increasing sound level. Three types of paradoxical latency shift were found: (1) stable, that does
not depend on sound duration, (2) duration-dependent, that grows with increasing sound duration, and (3) progressive, whose
magnitude increases with increasing sound level. The temporal properties of paradoxical latency shift neurons compare well
with those of neurons having long-lasting oscillatory responses, i.e. median inter-spike intervals and paradoxical latency
shift below 6 ms are overrepresented. In addition, oscillatory and paradoxical latency shift neurons behave similarly when
tested with tones of different durations. Temporal properties of oscillation and PLS found in the IC of fruit-eating bats
are similar to those found in the IC of insectivorous bats using downward frequency-modulated echolocation calls. 相似文献
11.
Temporal selectivity for complex signals by single neurons in the torus semicircularis of Pleurodema thaul (Amphibia: Leptodactylidae) 总被引:2,自引:0,他引:2
Mario Penna Wen-Yu Lin Albert S. Feng 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(4):313-328
Responses of auditory neurons in the torus semicircularis (TS) of Pleurodema thaul, a leptodactylid from Chile, to synthetic stimuli having diverse temporal patterns and to digitized advertisement calls of
P. thaul and three sympatric species, were recorded to investigate their temporal response selectivities. The advertisement call of
this species consists of a long sequence of sound pulses (a pulse-amplitude-modulated, or PAM, signal) having a dominant frequency
of about 2000 Hz. Each of the sound pulses contains intra-pulse sinusoidal-amplitude-modulations (SAMs). Synthetic stimuli
consisted of six series in which the following acoustic parameters were systematically modified, one at a time: PAM rate,
pulse duration, number of pulses, and intra-pulse SAM rate. The carrier frequency of these stimuli was set at the characteristic
frequency (CF) of the isolated units (n = 47). Response patterns of TS units to synthetic call variants reveal different degrees of selectivities for each of the
temporal variables, with populations of neurons responding maximally to specific values found in the advertisement call of
this species. These selectivities are mainly shaped by neuronal responsiveness to the overall sound energy of the stimulus
and by the inability of neurons to discharge to short inter-pulse gaps.
Accepted: 30 October 1996 相似文献
12.
Hisaaki Namba Toshiki Nagayama Masakazu Takahata 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(5):463-472
The role of non-spiking local interneurones in the synaptic interactions between abdominal extension-evoking descending interneurones
and uropod motor neurones in the terminal abdominal ganglion of the crayfish Procambarus clarkii (Girard) was investigated electrophysiologically. Continuous electrical stimulation of the lateral region of the 3rd-4th
abdominal connective that included abdominal extension evoking interneurones excited the opener motor neurones and inhibited
the closer, reductor motor neurone. Spikes from a single descending interneurone evoked consistent and short latency (0.8–0.9
ms) excitatory postsynaptic potentials (e.p.s.ps) in the opener motor neurones, and evoked rather long-latency (1.5–2.7 ms)
inhibitory postsynaptic potentials (i.p.s.ps) in the reductor motor neurone. Many non-spiking interneurones also received
depolarizing p.s.ps (0.8–2.5 ms in latency) that were usually faster than i.p.s.ps of the reductor motor neurone if both neurones
were recorded sequentially in the same preparation. Non-spiking interneurones received convergent inputs from several descending
interneurones and made inverting connection with the reductor motor neurone. Elimination of descending inputs to a particular
non-spiking interneurone could reduce the inhibitory response of the reductor motor neurone. These observations strongly suggested
that descending inhibitory inputs to the closer, reductor motor neurone were mediated by non-spiking interneurones. Furthermore,
some non-spiking interneurones made output connections with the opener motor neurones. The disynaptic pathway through non-spiking
interneurones is significant to control and modulate the opening pattern of the uropod during abdominal extension.
Accepted: 27 December 1996 相似文献
13.
Seasonal changes in fatty acid composition associated with cold-hardening in third instar larvae of Eurosta solidaginis 总被引:1,自引:1,他引:0
Valerie A. Bennett Nancy L. Pruitt Richard E. Lee Jr. 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(4):249-255
Third-instar larvae of the goldenrod gall fly Eurosta solidaginis (Diptera: Tephritidae) survive extended periods in winter during which tissue water is frozen. Both low temperature and reduced
water activity during freezing present challenges for the structural integrity of cellular lipids. Fatty acids of both phospholipids
and triacylglycerols from fat body cells of E. solidaginis were analyzed throughout fall and early winter, a period that encompasses the acquisition of freeze-tolerance, to determine
if adaptations to freezing include changes in fatty acid unsaturation. The five most abundant fatty acids from both fractions
were (in decreasing order) oleic (40–65%), palmitoleic (18–20%), palmitic (12–17%), linoleic (5–10%), and stearic acids (4 –7%).
This represents a typical complement of Dipteran fatty acids, although oleic acid levels were higher in E. solidaginis than those reported from other Dipterans (˜28%; Downer 1985). From September to November, monounsaturates increased from
59 to 70% in phospholipids at the expense of saturated fatty acids (25% –20%) suggesting activation of a Δ9-desaturase enzyme. These changes resulted in an increase in the ratio of unsaturated to saturated fatty acids (U/S) from
3.0 to 4.2, although there was no change in the average number of double bonds per fatty acid (unsaturation index, UI ≈ 1.2
in phospholipids and 0.9 in triacylglycerols throughout the season). These changes were temporally correlated to decreasing
ambient temperatures and increasing larval and fat body cell freeze-tolerance.
Accepted: 31 October 1996 相似文献
14.
Atle Wibe Anna-Karin Borg-Karlson Torbjörn Norin Hanna Mustaparta 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(6):585-595
Naturally produced plant volatiles, eliciting responses of single olfactory receptor neurons in the pine weevil, have been
identified by gas chromatography linked with mass spectrometry. The receptor neurons (n = 72) were classified in 30 types, according to the compound which elicited the strongest response in each neuron, 20 of
which compounds were identified. Most potent for 14 types of neurons (n = 50) were monoterpenes, including bicyclic (e.g. α-pinene, camphor and myrtenal) for 8 types (n = 32), monocyclic (limonene, carvone, α-terpinene) for 3 types (n = 12) and acyclic (e.g. β-myrcene and linalool) for 3 types (n = 6). Other compounds eliciting strongest responses of a neuron were five sesquiterpenes, including α-copaene and a farnesene-isomer,
and an anethole type which has no biosynthetic relationship with terpenes. Within one type, receptor neurons with quite selective
responses to the most potent compound as well as neurons with additional responses to several, structurally similar compounds
were found, indicating that the neurons may have the same functional types of membrane receptors, but different sensitivities.
Response spectra of neurons within the bicyclic-, mono-cyclic and acyclic types showed more overlapping than across the neuron
types. Minimal overlapping response spectra was found between monoterpene and sesquiterpene neurons. The results suggest that
this structure-activity relationship is significant for encoding plant odour information in the pipe weevil.
Accepted: 6 January 1997 相似文献
15.
Ole Rintek Madsen Jens-Erik Beck Jensen Ole Helmer S?rensen 《European journal of applied physiology and occupational physiology》1997,75(6):554-558
We investigated the reproducibility of total and regional body composition measurements performed on a dual energy X-ray
absorptiometer (DXA). A group of 38 women aged 21–81 (mean 52. 4) years was scanned twice with repositioning to determine
intra-observer reproducibility of measurements of bone mineral density (BMD, g · cm−2), bone mineral content (BMC, g), lean mass (LM, kg) and fat mass (FM, kg) of the total body and of the major subregions of
the body. In addition, the ability of the DXA machine to detect changes in LM and FM (simulated by placing 11.1 and 22.3 kg
porcine lard on the body of 11 subjects) was examined. Coefficients of variations calculated from the root mean square averages
of individual standard deviations were as follows (BMD, BMC, FM, LM): 1.4%, 1.1%, 1.4%, 1.7% (total body), 2.2%, 2.1%,-,-
(head), 2.8%, 2.8%, 2.0%, 2.2% (trunk), 3.6%, 3.9%, 4.0%, 4.9% (arms), 2.7%, 1.3%, 2.6%, 2.8% (legs). Percentage fat (%fat)
of exogenous lard was 81.3 (SD 3.5)% as assessed by the absorptiometer which corresponded well with the result of chemical
analysis (82.8%). Estimated %fat of exogenous lard was not influenced by initial body mass or percentage body fat. Percentages
of expected mean values with 11.1 kg lard placed on the body were 99.9 (SD 0.3) for body mass, 100.5 (SD 2.1) for LM, and
99.5 (SD 3.5) for FM. BMD was overestimated by 3.2% (P < 0.005) with 11.1 kg lard on the body. BMD as well as BMC increased significantly with 22.3␣kg lard on the body (P < 0.005). The results showed that BMD, BMC, LM, and FM of the total body were precisely estimated by the DXA machine used.
Regional measurements were less precise. Changes in total body soft tissue composition were precisely and accurately estimated.
The lard placed on the body falsely affected BMD and BMC measurements. Changes in body mass could have a similar effect.
Accepted: 6 January 1997 相似文献
16.
Evidence for NO-dependent vasodilation in the trout (Oncorhynchus mykiss ) coronary system 总被引:1,自引:0,他引:1
T. Mustafa C. Agnisola J. K. Hansen 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(2):98-104
The effects of l-arginine, and its analogues N
ω-nitro-l-arginine methyl ester and N
ω-nitro-l-arginine on vascular resistance were investigated in the intact coronary system of an isolated non-working trout heart preparation.
l-Arginine, at 10–8 mol · l–1induced a slight vasodilatory effect (max 10%). N
ω-nitro-l-arginine methyl ester and N
ω-Nitro-l-arginine in the range 10–8–10–4 mol · l–1 caused dose-dependent increases in coronary resistance. The vasodilatory action of l-arginine was abolished when the preparation was pretreated with 10–4 mol · l–1
N
ω-nitro-l-arginine or N
ω-nitro-l-arginine methyl ester. Nitroprusside alone at 1 mmol · l–1 induced a maximum vasodilation (30%) of the coronary system. Methylene blue a known inhibitor of guanylate cyclase, induced
a strong vasoconstriction (already significant at 10–5 mol · l–1) and was able to overcome the vasodilative effect of nitroprusside. The endothelial nitric oxide agonists acetylcholine and
serotonin, established in mammalian vessels, also mediate vasodilation in trout coronary system. In 50% of preparations, acetylcholine
induced a biphasic response with vasodilation at low concentration (max 15% at 10–8 mol · l–1). Serotonin displayed a dose-response vasodilation in the range 10–8–10–4 mol · l–1 (max 20%). These vasodilative effects were reduced or abolished by 10–4 mol · l–1
l-NA. These data support the existence of NO-mediated vasodilation mechanisms in the trout coronary system.
Accepted: 1 July 1996 相似文献
17.
A. K. Tryba H. B. Hartman 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(3):215-221
Receptors monitoring muscle force innervate the opener muscle apodeme in the walking legs of the blue crab, Callinectes sapidus. Biocytin backfills reveal 9–15 bipolar neurons with somata as large as 60 μm positioned at the distal end of the apodeme.
Sensory endings insert into the apodeme and are in series with the opener muscle. The axons of these neurons form the opener
apodeme sensory nerve that merges with the most distal branch of the opener motor nerve. Recordings reveal that the receptors
are not spontaneously active nor do they respond to passive muscle stretch. Isometric muscle contraction evoked by stimulating
the opener excitor motor neuron is the adequate stimulus for receptor firing. Most significant is the finding that during
contraction, over a wide range of forces, the firing rate of individual receptors closely parallels the rate of change of
isometric force. The peak instantaneous frequency typically occurs at the force derivative maximum, but not at maximum force
development. Thus, receptors of the opener apodeme sensory nerve more closely monitor changes in isometric force rather than
the total force achieved.
Accepted: 20 September 1996 相似文献
18.
19.
P. J. Fonseca A. V. Popov 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(4):417-427
1. Laser vibrometry and acoustic measurements were used to study the biophysics of directional hearing in males and females
of a cicada, in which most of the male tympanum is covered by thick, water filled tissue “pads”. 2. In females, the tympanal
vibrations are very dependent on the direction of sound incidence in the entire frequency range 1–20 kHz, and especially at
the main frequencies of the calling song (3–7 kHz). At frequencies up to 10 kHz, the directionality disappears if the contralateral
tympanum, metathoracic spiracle, and folded membrane are blocked with Vaseline. This suggests some pressure-difference receiver
properties in the ear. 3. In males, the tympanal vibrations depend on the direction of sound incidence only within narrow
frequency bands (around 1.8 kHz and at 6–7 kHz). At frequencies above 10–12 kHz, the directionality appears to be determined
by diffraction, and the ear seems to work as a pressure receiver. The peak in directionality at 6–7 kHz disappears when the
contralateral timbal, but not the tympanum, is covered. Covering the thin ventral abdominal wall causes the peak around 1.8 kHz
to disappear. 4. Most observed tympanal directionalities, except around 1.8 kHz in males, are well predicted from measured
transmissions of sound through the body and measured values of sound amplitude and phase at the ears at various directions
of sound incidence.
Accepted: 18 October 1996 相似文献
20.
Sherri M. Jones Timothy A. Jones Roshni Shukla 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(6):631-638
Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred
within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and
amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms−1 ranged from 1265 ± 208 μs (P1, N = 18) to 4802 ± 441 μs (N4, N = 13). Amplitudes ranged from 3.72 ± 1.51 μV (P1/N1, N = 18) to 1.49 ± 0.77 μV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from −38.7 ± 7.3 μs dB−1 (P1, N = 18) to −71.6 ± 21.9 μs dB−1 (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 ± 0.08 μV dB−1 (P1/N1, N = 18) to 0.07 ± 0.04 μV dB−1 (P3/N3, N = 11). The mean response threshold across all animals was −21.83 ± 3.34 dB re: 1.0 g ms−1 (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity.
Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and
specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide
a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail.
Accepted: 18 January 1997 相似文献