Orofacial dyskinesia, frontal lobe dysfunction, and coping in older people with psychosis.

Objective: To investigate whether orofacial tardive dyskinesia (OTD) is associated with frontal lobe dysfunction and whether either are related to the coping abilities independent of psychiatric symptoms in older people with psychotic disorders.

Methods: A total of 52 patients, aged over 65 years or over, who satisfied International Classification of Diseases, Tenth Revision criteria for psychotic disorders (F20-F29) were recruited into the study. OTD was measured using the Abnormal Involuntary Movements Scale and Waddington et al.

Neonatal sensorineural hearing loss affects synaptic density in the auditory midbrain.

We examined the effect of neonatal sensorineural hearing loss on synaptic density in the central nucleus of the inferior colliculus (ICC) of adult cats to evaluate the role of auditory experience in synaptogenesis. Three groups of animals were used: bilaterally deafened, unilaterally deafened and normal hearing controls. Synaptic density in bilaterally deafened animals was significantly lower than in normal hearing animals.

Features of the auditory development of the short-tailed Brazilian opossum, Monodelphis domestica: evoked responses, neonatal vocalizations and synapses in the inferior colliculus.

The onset of hearing in anesthetized South American opossums (Monodelphis domestica) was determined by the measurement of evoked potentials to click stimuli from the vertex of the skull immediately over the inferior colliculus. Evoked potentials were first recorded at postnatal day 24 at a threshold of 83 dB SPL; thresholds declined over subsequent weeks to below 58 dB at 40 days. Isolation calls emitted by the pups had stereotypic spectra with peaks at near 13 kHz and an octave higher.

Development of hearing and vocalization in a marsupial, the Northern Quoll, Dasyurus hallucatus.

The development of hearing was studied in the Northern Quoll, a nocturnal marsupial carnivore whose young are born into a pouch in an immature state after about 21 days in utero. Startle responses to noise bursts of 105 dB sound pressure level first appeared at 60 days after arrival in the pouch, but only to occasional stimuli; forelimb rather than whole body twitches were evoked. The latter were elicited regularly at 67 days onward.

Features of the structural development of the inferior colliculus in relation to the onset of hearing in a marsupial: the northern quoll, Dasyurus hallucatus.

The time course of synaptogenesis and the arrival and myelination of afferent connections were studied in the developing inferior colliculus (IC) of a marsupial, the Northern Quoll, and related to the onset of hearing and patency of peripheral auditory structures in that species. The quoll is born after 3 weeks of intrauterine growth and completes its development in a pouch for a further 80 days before weaning. Synaptic terminals in the IC at 9 days after arrival in the pouch were extremely rare and were associated with very low vesicle numbers.

The anatomy of the cochlear nuclei and superior olivary complex of arboreal Australian marsupials.

Cytoarchitectural and morphometric analyses were carried out on the cochlear nuclear and superior olivary complexes of nine representative possums and gliders, members of a large group of nocturnal, arboreal Australian marsupials, many of which have well developed vocalizations. The cochlear nuclear complex was displaced medial to the restiform body in all species; this has previously been reported in other marsupials. The dorsal cochlear nucleus was generally very much larger than any other nucleus in this complex.

Sensitivity to interaural intensity differences of neurons in primary auditory cortex of the cat. I. types of sensitivity and effects of variations in sound pressure level.

1. Interaural intensity differences (IIDs) provide the major cue to the azimuthal location of high-frequency narrowband sounds. In recent studies of the azimuthal sensitivity of high-frequency neurons in the primary auditory cortex (field AI) of the cat, a number of different types of azimuthal sensitivity have been described and the azimuthal sensitivity of many neurons was found to vary as a function of changes in stimulus intensity.

The auditory neurobiology of marsupials: a review.

The marsupials, the large group of mammals which develop during fetal life in an externalized pouch, have been given little attention by auditory neurobiologists. In this review the structure of the auditory systems of the handful of marsupials which have been studied is described, the course of auditory development mapped, and the behavioral and electrophysiological manifestations of hearing examined. It is argued that research on the highly accessible developing marsupial will provide information about the development of hearing difficult to obtain from, but applicable to all, mammalian species.

Hearing, vocalization and the external ear of a marsupial, the northern Quoll, Dasyurus hallucatus.

As part of a continuing study of the development of the marsupial auditory system, auditory brainstem responses (ABR) were recorded and an ABR audiogram was constructed for five female Northern Quolls (Dasyurus hallucatus), which are nocturnal carnivores. The best frequency for hearing lies between 8 and 10 kHz, and at 50 dB SPL there is a range from about 0.5 to 40 kHz.

The morphological development of the inferior colliculus in a marsupial, the Northern quoll (Dasyurus hallucatus).

As a part of a project concerning the development of hearing, some features of the morphological development of the inferior colliculus were studied in a marsupial, the Northern quoll or native cat (Dasyurus hallucatus). Marsupials are of particular interest in developmental studies because much embryonic development occurs outside the uterus, in the pouch. Nissl-stained material was prepared from pouch-young at various ages between 11 and 81 days, and for a number of adults.

The responses of neurons in subdivisions of the inferior colliculus of cats to tonal, noise and vocal stimuli.

The aim of this study was to gain information from anesthetized cats about the differential coding properties of neurons in the three major subdivisions of the inferior colliculus: the central (CNIC) and external (EN) nuclei and dorsal cortex (DC). Stimuli were presented in the free field from a speaker facing the contralateral pinna. For each unit, the characteristic frequency (CF, where threshold was lowest) was determined, and impulse rates to CF tone bursts, noise bursts and four feline vocal stimuli were measured as a function of increasing sound pressure level (rate/level functions).

Plasticity of auditory cortex associated with sensorineural hearing loss in adult C57BL/6J mice.

The representation of frequency was mapped in the primary auditory cortex (AI) of C57BL/6J (C57) mice during young adulthood (1.5-2 months) when hearing is optimal, and at 3, 6, and 12 months of age, a period during which progressive, high frequency, sensorineural hearing loss occurs in this strain. Maps were also obtained from CBA/CaJ mice which retain good hearing as they age.

Azimuthal processing in the posterior auditory thalamus of cats.

The responses to free-field acoustic stimuli of 157 units in the auditory thalamus of anesthetized cats were studied in relation to the localization of pure tone stimuli in the azimuthal plane. Units were classified as 'directional' if their firing rates at sound levels in excess of 20 dB above threshold varied by more than 50% as a function of azimuth. Sixty-five % of the units in the nucleus of the brachium of the inferior colliculus and 30% in the ventral division of the medial geniculate body were found to be directional, suggesting different processing channels for sound localization between colliculus and cortex.

Neurogenesis in the brain auditory pathway of a marsupial, the northern native cat (Dasyurus hallucatus).

Neurogenesis in the auditory pathway of the marsupial Dasyurus hallucatus was studied. Intraperitoneal injections of tritiated thymidine (20-40 microCi) were made into pouch-young varying from 1 to 56 days pouch-life. Animals were killed as adults and brain sections were prepared for autoradiography and counterstained with a Nissl stain.

Rate-level functions of neurons in the inferior colliculus of cats measured with the use of free-field sound stimuli.

1. The responses as a function of stimulus level of 125 single units in the inferior colliculus of anesthetized cats were studied with the use of free-field acoustic stimuli. 2.

Neurons in the inferior colliculus of cats sensitive to sound-source elevation.

The sensitivity to variations in sound-source elevation was studied in 48 units, previously examined as to their azimuthal sensitivity, of the inferior colliculi of cats. Of these units, 36 were directionally-sensitive (firing rate varied by more than 50% across the range of positions studied) to both azimuthal and elevational changes. Elevation sensitivity was common to noise stimuli (19/25 units) and pure tones in excess of 6 kHz (17/17 units).

Azimuthal sensitivity of neurons in primary auditory cortex of cats. II. Organization along frequency-band strips.

1. The organization of azimuthal sensitivity of units across the dorsoventral extent of primary auditory cortex (AI) was studied in electrode penetrations made along frequency-band strips of AI. Azimuthal sensitivity for each unit was represented by a mean azimuth function (MF) calculated from all azimuth functions obtained to characteristic frequency (CF) stimuli at intensities 20 dB or more greater than threshold.

Azimuthal sensitivity of neurons in primary auditory cortex of cats. I. Types of sensitivity and the effects of variations in stimulus parameters.

1. Preliminary to studying the organization of azimuthal sensitivity of neurons along frequency-band strips in the primary auditory cortex (AI) of cat (see companion paper), this study examined the sensitivity of 251 units in cat AI to variations in the azimuthal location of sound sources in the frontal hemifield. Most units (231) were tested with tones at the characteristic frequency (CF; frequency to which the unit had the lowest threshold).

Neurogenesis in a marsupial: the brush-tailed possum (Trichosurus vulpecula). I. Visual and auditory pathways.

The times of origin of neurons in the visual and auditory systems were studied in a marsupial, the brush-tailed possum, using tritiated thymidine autoradiography. Within the subcortical visual pathways, most neurons are generated between postnatal days 5 and 21, and the neurons of the primary visual cortex up to postnatal day 68. In the subcortical auditory pathways, most neurons are generated between postnatal days 5 and 28, and all auditory cortex neurons have appeared by postnatal day 46.

Peripheral and central auditory specialization in a gliding marsupial, the feathertail glider, Acrobates pygmaeus.

Two specialized features are described in the auditory system of Acrobates pygmaeus, a small gliding marsupial. Firstly, the ear canal includes a transverse disk of bone that partly occludes the canal near the eardrum. The resultant narrow-necked chamber above the eardrum appears to attenuate sound across a broad frequency range, except at 27-29 kHz at which a net gain of sound pressure occurs.

Auditory forebrain organization of an Australian marsupial, the northern native cat (Dasyurus hallucatus).

Structures and connections of auditory forebrain regions of the Northern native cat, a member of one of the most primitive families among Australian marsupials, have been examined anatomically by using anterograde and retrograde tracing techniques with wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) after defining the acoustically responsive neocortical area physiologically. The structure of the medial geniculate body (MG) was similar to that described in other species. The results obtained from a case with a WGA-HRP injection into the MG showed that the MG strongly projects to the lateral amygdaloid nucleus (LAmy) and the putamen as well as the auditory neocortex (ACx).

Connections of the primary auditory cortex in the common marmoset, Callithrix jacchus jacchus.

The afferent and efferent connections of the primary auditory cortex (AI) of common marmosets were traced following small injections of wheat germ agglutinin conjugated with horseradish peroxidase (WGA-HRP) made at best frequency (BF)-defined sites in the AI. After the injections the animals remained anesthetized for 15-23 hours; they were then perfused transcardially with fixative and the brains were processed for WGA-HRP reaction product. Examination of the disposition of labelled material revealed the following results.

The representation of stimulus azimuth by high best-frequency azimuth-selective neurons in the central nucleus of the inferior colliculus of the cat.

The responses to changes in stimulus azimuth of 220 high best-frequency (BF) (greater than 3 kHz) units in the central nucleus of the inferior colliculus of the anesthetized cat were studied with BF tones (220 units) and noise stimuli (84 units). By this means we hoped to gain some insights into the way the azimuthal locations of high BF stimuli were represented in the inferior colliculus. For each unit the discharge rate was determined for stimuli located along a plane tilted at 20 degrees above the horizontal.

Differential neural projections to regions of the inferior colliculus of the cat responsive to high frequency sounds.

Iontophoretic injections of horseradish peroxidase were made in the vicinity of high best frequency neurons in the central nucleus of the inferior colliculus of the cat. Retrogradely labelled cells were found in most major auditory nuclei known to provide afferent input to the central nucleus, and were distributed in accordance with the known tonotopic organization of these nuclei. However, different injection sites gave rise to patterns of brain stem labelling that differed from one experiment to the next, in spite of the similarities in injection site best frequency.