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1.
A 30-second exposure (priming) to a loud noise induced a long-lasting susceptibility to audiogenic seizures and a 15-decibel decrease in threshold to the Preyer acoustic startle reflex in C57BL/6J mice. Both effects were absent when the subjects were primed in one ear and subsequently tested in the contralateral ear. It was postulated that the primary effect of priming is an increase in auditory sensitivity due to changes in the ear itself or in those parts of the auditory system which receive their input exclusively from one ear.  相似文献   

2.
Otoacoustic emissions or OAEs (reflections of cochlear energy produced during the processing of sound) were measured in response to two types of stimuli, rapid clicks and sustained tones, in each ear of neonates. OAEs were larger to tones when elicited in the left ear and to clicks when elicited in the right. This finding is similar to those of enhanced processing of tones in right auditory cortical areas and of rapid stimuli on the left, given strong crossed connections from ear to brain. These findings indicate that processing at the level of the ear may facilitate lateralization of auditory function in the brain.  相似文献   

3.
Functional asymmetry of the human brain   总被引:1,自引:0,他引:1  
Verbal and nonverbal memorization skills were tested before and after electroconvulsive shocks to the left, right, or both cerebral hemispheres of neurologically normal patients. As predicted, decrements for the left-hemisphere-shocked group were larger on the verbal than nonverbal tasks, while the reverse was true for the right-hemisphere-shocked group. Largest decrements on both tasks were shown by the bilaterally shocked group.  相似文献   

4.
Vision guides the adjustment of auditory localization in young barn owls   总被引:4,自引:0,他引:4  
Barn owls raised with one ear plugged make systematic errors in auditory localization when the earplug is removed. Young owls correct their localization errors within a few weeks. However, such animals did not correct their auditory localization errors when deprived of vision. Moreover, when prisms were mounted in front of their eyes, they adjusted their auditory localization to match the visual error induced by the prisms, as long as the visual and auditory errors were within the same quadrant of directions. The results demonstrate that, during development, the visual system provides the spatial reference for fine-tuning auditory localization.  相似文献   

5.
Interhemispheric asymmetries of different magnitudes were observed in human cortical auditory evoked responses to speech and sound-effect stimuli. The wave with peak asymmetry occurred 100 milliseconds after signal onset. The amount of asymmetry of the amplitude of this wave was related to the meaningfulness to the subject of the auditory stimulus rather than to the mere use of verbal versus nonverbal materials.  相似文献   

6.
In primates, certain areas of the frontal cortex play a role in guiding movements toward visual or auditory objects in space. The projections from auditory centers to the frontal cortex of the bat Pteronotus parnellii were examined because echolocating bats utilize auditory cues to guide their movements in space. An area in the frontal cortex receives a direct projection from a division of the auditory thalamus, the suprageniculate nucleus, which in turn receives input from the anterolateral peri-olivary nucleus, an auditory center in the medulla. This pathway to the frontal cortex bypasses the main auditory centers in the midbrain and cortex and could involve as few as four neurons between the cochlea and the frontal cortex. The auditory cortex is also a major source of input to the frontal cortex. This area of the frontal cortex may link the auditory and motor systems by its projections to the superior colliculus.  相似文献   

7.
The mucosa lining the cavity of the middle ear of sea lions contains a complex network of venous channels and sinuses. During dives the pressure within the middle ear may be equalized with that in the external auditory meatus either by the distention or depression of the mucosa due to the presence or absence of blood in the sinuses.  相似文献   

8.
Psychophysiological measurements have indicated that the right cerebral hemisphere processes noises and other nonverbal data and that the left cerebral hemisphere processes verbal material. Direct physiological measurements, as expressed in summated auditory evoked cortical responses, unequivocally demonstrate that click noises show a greater amplitude of initial output over the right brain, and that verbal stimuli produce either equal or higher amplitudes of output over the left cerebral hemisphere.  相似文献   

9.
Julesz has shown that cross-correlations between two patterns that appear random to either eye alone can give rise to the perception of form and depth when viewed stereoscopically. We produced auditory analogs by presenting eight simultaneous and continuous sine waves to both ears and by either phaseshifting or frequency-shifting one of them relative to its counterpart in the opposite ear. Particular tones were shifted in sequence such that a melody was heard which was undetectable by either ear alone.  相似文献   

10.
Evoked potentials to click at auditory cortex were recorded from cats deprived of middle ear muscles. Variations in the amplitude of the response after surgery indicate that the participation of these muscles in habituation, conditioning, and distraction must be minimal.  相似文献   

11.
The praying mantis, thought to be deaf, possesses a sensitive and specialized acoustic sense. Neural recordings show that the auditory system responds primarily to ultrasound between 25 and 45 kilohertz with thresholds of 55 to 60 decibels. Other insects with auditory tympana possess paired, laterally placed ears; the mantis has only a single ear that is located in the ventral midline between the metathoracic legs. Some species of mantis abruptly and dramatically alter their flight path when stimulated with ultrasonic pulses, suggesting a behavioral response to insectivorous echo-locating bats.  相似文献   

12.
For seasonally breeding vertebrates, reproductive cycling is often coupled with changes in vocalizations that function in courtship and territoriality. Less is known about changes in auditory sensitivity to those vocalizations. Here, we show that nonreproductive female midshipman fish treated with either testosterone or 17beta-estradiol exhibit an increase in the degree of temporal encoding of the frequency content of male vocalizations by the inner ear that mimics the reproductive female's auditory phenotype. This sensory plasticity provides an adaptable mechanism that enhances coupling between sender and receiver in vocal communication.  相似文献   

13.
A reticular stimulation producing a powerful arousal reaction decreases the potential in the cochlear nucleus evoked by a click. This reduction results from the contraction of the middle ear muscles, which lessens the pressure transmitted to the cochlea, and is not due to a direct neural inhibitory effect at the level of the first synapse of the auditory pathway.  相似文献   

14.
Experimentally induced visual projections into auditory thalamus and cortex   总被引:13,自引:0,他引:13  
Retinal cells have been induced to project into the medial geniculate nucleus, the principal auditory thalamic nucleus, in newborn ferrets by reduction of targets of retinal axons in one hemisphere and creation of alternative terminal space for these fibers in the auditory thalamus. Many cells in the medial geniculate nucleus are then visually driven, have large receptive fields, and receive input from retinal ganglion cells with small somata and slow conduction velocities. Visual cells with long conduction latencies and large contralateral receptive fields can also be recorded in primary auditory cortex. Some visual cells in auditory cortex are direction selective or have oriented receptive fields that resemble those of complex cells in primary visual cortex. Thus, functional visual projections can be routed into nonvisual structures in higher mammals, suggesting that the modality of a sensory thalamic nucleus or cortical area may be specified by its inputs during development.  相似文献   

15.
Language-relevant processing of auditory signals is lateralized and involves the posterior part of Brodmann area 22. We found that the functional lateralization in this area was accompanied by interhemispheric differences in the organization of the intrinsic microcircuitry. Neuronal tract tracing revealed a modular network of long-range intrinsic connections linking regularly spaced clusters of neurons. Although the cluster diameter was similar in both hemispheres, their spacing was about 20 percent larger in the left hemisphere. Assuming similar relations between functional and anatomical architecture as in visual cortex, the present data suggest that more functionally distinct columnar systems are included per surface unit in the left than in the right area 22.  相似文献   

16.
语音质量是评价通信系统的一项重要指标。现有的语音质量感知评估算法采用基于Bark谱的感知模型,其算法复杂度较大,并且对于人耳的频率选择性的模拟存在不足。针对这一问题,本文提出一种新的客观语音质量评估方法,采用更加符合人耳听觉特性的Gammatone滤波器组提取特征参数,计算原始语音与失真语音的平均失真距离,并由主观平均意见分值和归一化平均失真距离之间的映射关系求出客观平均意见分值。实验表明,与感知评估方法相比,本文所提出算法的计算复杂度大大降低,同时保持了客观平均意见分值与主观平均意见分值之间的高相关度。  相似文献   

17.
Airborne sound and substrate vibration each elicit electrical responses below the surface of the tectum in species of three families of snakes. Tones of 50 to 1000 hertz evoke responses independently of substrate vibration. Sensitivity to locally applied sound is present over much of the body surface. This sensitivity is attributed to the auditory nerve, because it is not altered by spinal section but is eliminated by destruction of the inner ear.  相似文献   

18.
Delaying the return of a speaker's vocal output to his ears (the auditory feedback) radically changes his speech (1). The present report concerns the effect of delayed auditory feedback on simple key-tapping tasks. Evidence is presented which indicates that changes in speech and key tapping under delayed auditory feedback are analogous.  相似文献   

19.
Universal positive correlations between different cognitive tests motivate the concept of "general intelligence" or Spearman's g. Here the neural basis for g is investigated by means of positron emission tomography. Spatial, verbal, and perceptuo-motor tasks with high-g involvement are compared with matched low-g control tasks. In contrast to the common view that g reflects a broad sample of major cognitive functions, high-g tasks do not show diffuse recruitment of multiple brain regions. Instead they are associated with selective recruitment of lateral frontal cortex in one or both hemispheres. Despite very different task content in the three high-g-low-g contrasts, lateral frontal recruitment is markedly similar in each case. Many previous experiments have shown these same frontal regions to be recruited by a broad range of different cognitive demands. The results suggest that "general intelligence" derives from a specific frontal system important in the control of diverse forms of behavior.  相似文献   

20.
Mate recognition in frogs requires congruence of call characters, such as dominant frequency, and properties ofthe auditory system, such as frequency sensitivity of inner ear organs. Two neighboring populations of cricket frogs (Acri crepitans) exhibit statistically significant differences in the dominant frequency of the advertisement call and the frequency to which the basilar papilla of the inner ear is most sensitive. Call frequency and frequency sensitivity are matched within but differ between populations. These characters usually are negatively correlated with body size, and thus their congruence and coevolution often is explained by pleiotropic effects of size. However, within this species call frequency and frequency sensitivity ofthe basilar papilla evolved independent of body size, yielding local mate preferences that could contribute to genetic differentiation among neighboring populations.  相似文献   

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