Parental behavior in the mouse: effects of lesions in the entorhinal/piriform cortex.

The effects of bilateral radiofrequency lesions in the region of the entorhinal and piriform cortex (ENT/PIR cortex) on pup-retrieving and ultrasound-elicited pup-searching behavior were investigated in ovariectomized estrogen-treated female mice, which were sensitized to pups by co-caring for a litter for 5 days together with the mother (FoEBex), as well as in primiparous lactating females (Flact). A further group of FoEBex were rendered anosmic by an intranasal treatment with zinc sulfate-solution before the sensitization period and tests for parental motivation. Both pup-retrieving and pup-searching behavior were disturbed to the same extent by ENT/PIR lesions and ZnSO4-induced anosmia in FoEBex.

Development of tonotopy in the inferior colliculus. I. Electrophysiological mapping in house mice.

The development of the size and tonotopy of the mouse inferior colliculus (IC) was studied at postnatal ages of 9-20 days. During that time, the size of the IC remained constant in all 3 planes (rostrocaudal, mediolateral dorsoventral). At day 10, the first low-frequency responses without tonotopy could be recorded from neurons in the rostral and central parts of the central nucleus sparing its caudal part, very medial portions, the medial part (M) of the central nucleus, the dorsal cortex and the lateral nucleus.

Immunocytochemical localization and quantitation of estrogen-binding cells in the male and female (virgin, pregnant, lactating) mouse brain.

Estrogen-binding cells in the brains of male, virgin, pregnant, and lactating female mice were localized and quantified using an immunocytochemical technique. Nuclear estrogen-receptors were detected in cells of the midbrain periventricular gray, the cortical and medial amygdaloid nucleus, the arcuate nucleus and ventromedial nucleus of the hypothalamus, the anterior hypothalamic area and the preoptic area in animals of all 4 experimental groups. In virgin females, immunostaining was also seen in the hippocampus, the entorhinal and piriform cortex and in the septal nuclei.

Estradiol and parental experience, but not prolactin are necessary for ultrasound recognition and pup-retrieving in the mouse.

The effects of estradiol, prolactin and experience with pups on pup-retrieving and on the recognition of ultrasonic distress calls of the young by adult ovariectomized female mice were studied. Treatment with estradiol benzoate or experience with pups (for 5 days) induced pup-retrieving in 40% and 60% of the animals, respectively, as compared to 0% in inexperienced ovariectomized females. However, if pup-experience was achieved in the presence of estradiol, retrieving was shown by 90.

Neuronal discharge rate is unsuitable for encoding sound intensity at the inferior-colliculus level.

Rate-intensity functions from single neurons in the central nucleus of the inferior colliculus (ICC) of the cat in response to tone bursts and continuous noise were recorded. Only 6% of 64 quantitatively studied neurons had monotonic functions in response to tone bursts, 12.5% in response to continuous noise.

Complex sound analysis (frequency resolution, filtering and spectral integration) by single units of the inferior colliculus of the cat.

The central nucleus of the inferior colliculus (ICC) is a center of convergence of brainstem input and is critical for auditory information processing. Here, the analysis of complex sound spectra by single neurons in the ICC is investigated. Several measures of frequency resolution (excitatory/inhibitory tuning curves, effective bandwidths, critical ratio bands, critical bands derived using narrowband masking and two-tone separation paradigms) have been obtained from the responses of these neurons at sound pressure levels (SPL) up to 80 dB above the units' response thresholds (nearly 110 dB SPL).

Accessory pathway for sound transfer in a neotropical frog.

A portion of the lateral body wall overlying the lung cavity of the arboreal frog, Eleutherodactylus coqui, vibrates in response to free-field sound. Peak displacement amplitude of the body wall in response to a natural call note presented at 73 decibels sound pressure level is 1.70 X 10(-9) m, roughly 8 decibels less than that of the ipsilateral eardrum, as measured by laser Doppler vibrometry.

Haloperidol- and apomorphine-induced changes in pup searching behaviour of house mice.

Maternal pup searching behaviour of lactating house mice treated with apomorphine, haloperidol or saline was examined on a running board with a central depression as a nest. Pup searching was elicited by artificial ultrasonic stimuli: a female moved out from the nest either towards a 50 kHz tone (key stimulus) which is adequate to activate species specific pup searching behaviour or towards a 20 kHz tone (neutral stimulus), thus showing her preference for one of these stimuli. Under apomorphine (0.

Left hemisphere advantage in the mouse brain for recognizing ultrasonic communication calls.

In humans, sound perceived as speech is processed preferentially by the right ear and the left hemisphere of the brain. Among animals, such an advantage of one hemisphere (lateralization) in processing communication sound from other members of the species has so far been demonstrated only in macaque monkeys. I report here that in the house mouse, which has a very much less elaborate forebrain than man or macaque monkey, the ultrasonic calls that are emitted by young mice to evoke maternal caring behavior are preferentially recognized by the left hemisphere.

Inferior colliculus of the house mouse. I. A quantitative study of tonotopic organization, frequency representation, and tone-threshold distribution.

Electrophysiological mapping was used to study frequency representation in the inferior colliculus (IC) of the mouse. In the lateral nucleus (LN) only part of the frequency range of hearing was represented and tonotopicity was separate from that in the rest of the IC. Highest frequencies occupied the medial part (M) of the central nucleus (CN).

Auditory midbrain responses parallel spectral integration phenomena.

Resolving the frequency components of complex sound spectra including speech is an inherent, important accomplishment of the auditory nervous systems of vertebrates. The critical perceptual unit in the frequency domain, the critical bandwidth, has a simple functional equivalent within the principal midbrain auditory nucleus--the central nucleus of the inferior colliculus.

Behavioural studies on auditory development in mammals in relation to higher nervous system functioning.

The development of hearing measured behaviourally is compared in a quantitative way with studies on the physiological development in the auditory pathway of cats, house mice and humans. The similarity of time constants and of the beginning and end of the developments suggests that behavioural threshold sensitivity measured by unconditioned and conditioned reflexes is determined at or below the midbrain level.

Development of sound production in normal, isolated, and deafened kittens during the first postnatal months.

The development of calls (quantified by a series of acoustic parameters) of (a) normal, (b) socially isolated, and (c) deafened kittens that were released in four different situations has been studied from birth to 170 days of age. All call parameters studied except noise components show developmental changes that can be related to the development of (a) the vocal tract (fundamental frequency, harmonic with maximum intensity, upper-frequency limit and frequency range, occurrence of frequency, and intensity modulations), (b) feedback control through the auditory system (sound-pressure level, harmonic with maximum intensity, call-variability), and (c) motivational valuation of the releasing situations (duration). Isolated and deafened kittens displayed quantitative differences in certain call parameters compared with normal animals.

Noise masking of tone responses and critical ratios in single units of the mouse cochlear nerve and cochlear nucleus.

Responses of single units in the cochlear nerve and cochlear nucleus to tone bursts in a background of continuous white broadband noise were recorded. Tone and noise intensities ranged from threshold to saturation levels. Masking of the tone response by the noise was demonstrated by comparing peristimulus-time histograms and spike rates recorded during the tone and between tone presentations.

Localization of tones and noise in the horizontal plane by unrestrained house mice (Mus musculus).

House mice (Mus musculus, outbred strain NMRI) were trained to locate loudspeakers at the margin of a wire-mesh covered circular platform. Sound signals were tone bursts of 1, 15, 50 and 80 kHz and noise bursts (bandwidth 15-80 kHz). Localization acuity as represented by orientation angles (alpha) toward the speaker was determined at 5 radial distances from the centre of the platform.

Two-tone suppression in auditory nerve fibers of the green treefrog (Hyla cinerea).

The phenomenon of two-tone suppression was studied quantitatively in the peripheral auditory system of the green treefrog (Hyla cinerea). Linear relationships were found between best excitatory and best suppressor frequency, between response thresholds at these frequencies, between Q 10dB-values of excitatory and suppressor tuning curves and best excitatory frequency, and between both Q 10dB-values.

Postnatal development of absolute auditory thresholds in kittens.

Postnatal development of absolute auditory thresholds in the kitten was behaviorally measured from birth up to 1 mo of age. Unconditioned reactions to pure tones were observed for kittens up to Day 12, and conditioned responses were used for animals from Day 10 onward. At 1 day after birth, the first noticeable responses were obtained in 4 of 11 kittens at frequencies of .

Correlations between cochlear hair cell loss and shifts of masked and absolute behavioral auditory thresholds in the house mouse.

Masked and absolute behavioral auditory thresholds were measured in kanamycin-treated C3H mice with a significant damage or loss of outer hair cells (OHCs) near the cochlear base, and in 17--24-month-old NMRI mice with a significant loss of OHCs and inner hair cells (IHCs) in the basal region and of OHCs near the apex. A loss of IHCs is correlated with an increase in absolute thresholds. A moderate damage or loss of OHCs in a cochlear region had no effect on absolute thresholds but correlated with a decrease and other changes of characteristics of masked thresholds in the respective frequency regions.

Quantitative analysis of nerve fibre densities in the cochlea of the house mouse (Mus musculus).

Transverse sections of the cochlear nerve, silver-stained surface preparations of the cochlea, and silver- and osmium-stained tangential sections of the cochlea of the house mouse were made to determine the number and density of nerve fibres entering the organ of Corti and their distribution to inner and outer hair cells along the cochlear spiral. A number of 12,578 +/- 819 fibres was counted within the cochlear nerve, which is almost equal to the total number of 12,350 +/- 810 fibres entering the organ of Corti. The 12,350 fibres divide into 9,780 (= 79%) fibres running to the inner hair cells, 703 (= 6%) basilar (afferent) fibres and 1,867 (= 15%) upper tunnel radial (efferent) fibres innervating the outer hair cells.

Stiffness gradient along the basilar membrane as a basis for spatial frequency analysis within the cochlea.

Stiffness z of the basilar membrane of the house mouse against a displacement by sound was calculated from data on width and thickness of the membrane. Three functions of the kind log10z = ax + b were obtained which equally express the stiffness change in dependence on the locus x on the basilar membrane. These functions were compared with the one for frequency representation.

Comparative psychoacoustics: perspectives of peripheral sound analysis in mammals.

Psychophysical data on hearing in mammals are summarized. The data are then correlated to the anatomy and physiology of the ear. Common mechanisms of sound transfer and analysis in the acoustic system, with stress on the auditory periphery, are discussed.