ERP assessment of visual and auditory language processing in schizophrenia.

Language disturbance in schizophrenia has been recently attributed to disturbed priming mechanisms. In the present study, event-related potentials (ERPs), were recorded to final words in sentences presented to 13 chronic patients with schizophrenia and 12 normal controls. Half of the final words fit a sentence context and another half did not. The N400 (the ERP sensitive to language) latency was prolonged, and its amplitude was more negative to both correct and incorrect sentence endings in the group with schizophrenia relative to the group of normal controls. The early ERP components, N100 and P200, were similar in both groups. These results suggest that language abnormalities in schizophrenia are related to a dysfunction in the language system and not to a general cognitive dysfunction, and may be related to poor use of context in patients with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Filtered word testing in the assessment of children's central auditory abilities

The purpose of this study was to evaluate the effects of various cut-off frequencies on low-pass filtered speech discrimination test results obtained from children. Two groups of children, one presumed to have normal auditory perception and the other with auditory learning disabilities, were tested. Phonetically Balanced Kindergarten word list words were low-pass filtered at 1000 Hz, 750 Hz, and 500 Hz. The results indicate a clear separation of groups for the 1000 Hz filtered condition only. The implications of these preliminary test findings are discussed.     

Asymmetries in processing auditory nonverbal stimuli?

Reports in recent psychoacoustical literature have suggested that pitch and rhythm properties of nonverbal stimuli may be processed differently by the 2 cerebral hemispheres. A review of this literature and background information led to the following conclusions: (a) Perception of pitch stimuli probably does not require differential cerebral processing. Only when some type of novel or complex time structure is generated in the stimulus presentation do the responses of Ss reflect a cerebral dominance effect. (b) The asymmetries demonstrated in the results of rhythm experiments closely parallel those found in verbal experiments. In addition, rhythm structure may also provide a framework for the synthesis and analysis of all incoming perceptual information. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related changes in auditory temporal processing.

Two tone bursts separated by a silent interval and imbedded in a background white noise were presented to elderly subjects (M age?=?71.3 years) and young subjects (M age?=?22.2 years). Subjects were required to judge when the two tone bursts fused perceptually by adjusting the duration of tone-one. The bursts were separated by six discrete interstimulus intervals of 4, 8, 16, 24, 32, or 40 ms. The tone-two burst was held constant at 100 ms. Fusion point was defined as that critical tone-one duration at which the two tones fused (were perceived as one). Elderly subjects reached fusion point at longer critical tone-one durations than young subjects at each interval tested. The function relating tone-one duration and interval conformed to an exponential curve and is discussed with respect to an exponential decay model of the inhibitory interactions of neural systems responding to onsets and offsets of sensory events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serotonin and serotonin receptors in the central auditory system

Single channel currents were activated by GABA (0.5 to 5 microM) in cell-attached and inside-out patches from cells in the dentate gyrus of rat hippocampal slices. The currents reversed at the chloride equilibrium potential and were blocked by bicuculline (100 microM). Several different kinds of channel were seen: high conductance and low conductance, rectifying and "nonrectifying." Channels had multiple conductance states. The open probability (Po) of channels was greater at depolarized than at hyperpolarized potentials and the relationship between Po and potential could be fitted with a Boltzmann equation with equivalent valency (z) of 1. The combination of outward rectification and potential-dependent open probability gave very little chloride current at hyperpolarized potentials but steeply increasing current with depolarization, useful properties for a tonic inhibitory mechanism.     

Within- and between-dimensional processing in the auditory modality.

Participants made speeded target-nontarget responses to singly presented auditory stimuli in 2 tasks. In within-dimension conditions, participants listened for either of 2 target features taken from the same dimension; in between-dimensions conditions, the target features were taken from different dimensions. Judgments were based on the presence or absence of either target feature. Speech sounds, defined relative to sound identity and locale, were used in Experiment 1, whereas tones, comprising pitch and locale components, were used in Experiments 2 and 3. In all cases, participants performed better when the target features were taken from the same dimension than when they were taken from different dimensions. Data suggest that the auditory and visual systems exhibit the same higher level processing constraints. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rapid auditory processing in normal and disordered language development

A cell type, preadipocytes, isolated from the stroma of adult human adipose tissue appears capable of differentiating, in culture, into a cell with morphological features similar to that observed in terminally differentiated human adipocytes cultured under similar conditions. During this process of differentiation, preadipocytes develop extensive rough endoplasmic reticulum with prominent cisternae, the chromatin of most nuclei becomes decondensed and lipid bodies accumulate to levels observed in cultured adipocytes. Fibroblasts derived from non-adipose tissue do not undergo the same morphological changes when cultured under similar conditions.     

Cortical-hippocampal auditory processing identified by magnetoencephalography

We recorded magnetic and electrical responses simultaneously in an auditory detection task to elucidate the brain areas involved in auditory processing. Target stimuli evoked magnetic fields peaking at approximately the same latency of around about 400 msec (M400) over the anterior temporal, superior temporal, and parietal regions on each hemisphere. Equivalent current dipoles (ECDs) were analyzed with a time-varying multidipole model and superimposed on each subject's magnetic resonance image (MRI). Multiple independent dipoles located in the superior temporal plane, inferior parietal lobe, and mesial temporal region best accounted for the recorded M400 fields. These findings suggest that distributed activity in multiple structures including the mesial temporal, superior temporal, and inferior parietal regions on both hemispheres is engaged during auditory attention and memory updating.     

Deafness-induced plasticity in the mature central auditory system

Studies in rats and guinea pigs indicate that local changes in inhibitory transmitters may underlie deafness-induced plastic changes in electrophysiological responsiveness of cells of the mature central auditory system. Following 21 days of bilateral deafness there is an increase in evoked Fos-immunoreactive neurones in the central nucleus of the inferior colliculus (CIC) to contralateral cochlear electrical stimulation, compared with normal or 1-day deafened animals. Deafness is also associated with a dramatic reduction in the population of CIC neurones that respond with suppression of activity to electrical stimulation. Moreover, in vivo microdialysis reveals a marked decrease in gamma-aminobutyric acid (GABA) release from the CIC cells in deafened animals. The results may have general implications for the mediation of central nervous system plasticity induced by deafferentation of sensory input.     

Parallel processing in the auditory cortex of primates

Evidence from anatomical tracer studies as well as lesions of the primary auditory cortex (AI) indicate that the principal relay nucleus of the auditory thalamus, the ventral part of the medial geniculate (MGv), projects in parallel to AI and the rostral area on the supratemporal plane of the macaque monkey. The caudomedial area, by contrast, receives input from MGv only indirectly via AI, and neurons in this area are often tuned to the spatial location of a complex sound. The belt areas on the lateral surface of the superior temporal gyrus receive input from the primary areas. Neurons in these areas respond better to more complex stimuli, such as band-pass noise pulses of frequency-modulated sweeps, than to pure tones. Often neurons in the lateral belt respond well to species-specific communication calls. The hypothesis is put forward that the central auditory pathways in the macaque monkey are organized into parallel streams, similar to the visual system, one for the processing of spatial information, the other for the processing of auditory "patterns". Evidence from neuroimaging studies in humans with MRI and PET are consistent with this hypothesis. Virtual auditory space stimuli lead to selective activation of an inferior parietal region, whereas speech-like stimuli activate superior temporal regions.     

Subdivisions of auditory cortex and levels of processing in primates

In a series of experiments on New World and Old World monkeys, architectonic features of auditory cortex were related to tone frequency maps and patterns of connections to generate and evaluate theories of cortical organization. The results suggest that cortical processing of auditory information involves a number of functionally distinct fields that can be broadly grouped into four or more levels of processing. At the first level, there are three primary-like areas, each with a discrete pattern of tonotopic organization, koniocortical histological features, and direct inputs from the ventral division of the medial geniculate complex. These three core areas are interconnected and project to a narrow surrounding belt of perhaps seven areas which receive thalamic input from the major divisions of the medial geniculate complex, the suprageniculate/limitans complex, and the medial pulvinar. The belt areas connect with a lateral parabelt region of two or more fields that are almost devoid of direct connections with the core and the ventral division of the medial geniculate complex. The parabelt fields connect with more distant cortex in the superior temporal gyrus, superior temporal sulcus, and prefrontal cortex. The results indicate that auditory processing involves 15 or more cortical areas, each of which is interconnected with a number of other fields, especially adjoining fields of the same level.     

Contextual processing of multidimensional and unidimensional auditory stimuli.

Stimulus context (the distribution of stimulus values) can strongly affect both perception and judgment. In 14 experiments, the method of magnitude estimation revealed 2 fundamentally different kinds of context effect in loudness. An assimilative effect dominated when stimuli varied unidimensionally (in intensity only). But a contrastive, or adaptationlike, effect dominated when stimuli varied multidimensionally (in frequency and intensity). In Exp 15, direct loudness comparison revealed a potent, adaptational process specific to the signal frequency. Taken together, these and other results are compatible with the view that loudness perception and judgment reflect the net outcome of 2 different contextual processes: a relatively early (though probably not peripheral) process of perceptual adaptation and a later process of response-dependent assimilation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The assessment interview: Metalinguistic strategies in management assessment practices.

The use of pencil-and-paper tests in the field of executive assessment continues to provide generalized labels without giving meaningful answers about what is being measured. The almost universal employment of interviews in conjunction with these tests has permitted assessors to apply intuitive metalinguistic strategies to the assessments. It is this intuitive analysis of linguistic behavior that gives executive assessment its validity as a predictor of future success. The authors suggest that conscious, intentional linguistic approaches to assessment will enhance its effectiveness and advance the integration of the fields of psychology and behavioral linguistics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event-related brain activity associated with auditory pattern processing

One of the basic properties of the auditory system is the ability to analyse complex temporal patterns. Here, we investigated the neural activity associated with auditory pattern processing using event-related brain potentials. Participants were presented with a continuously repeating sequence of four tones with rare changes in either the frequency or timing of one of the tones. Both frequency- and time-deviant sounds generated mismatch negativity (MMN) waves that peaked at midline central electrode sites and inverted in polarity at inferior temporal and occipital sites, consistent with generators in the supratemporal plane. The MMN scalp topography was similar for the frequency- and time-deviant stimuli, suggesting that both spectral and temporal relations among elements of an auditory pattern are encoded in a unified memory trace.     

Left-ear superiority in children for processing auditory emotional material.

Investigated hemispheric asymmetries in children for processing auditory material varying in emotional intonation or verbal content. 31 kindergartners, 32 4th graders, and 32 8th graders reported on the emotional content and on the verbal content of dichotically presented sentences. Ss listened to tapes of 4 phrases spoken in tones that were happy, sad, angry, or neutral and to sentences that varied in verbal content only. Ss also completed a handedness questionnaire and a hearing test. All age groups showed a left-ear advantage for reporting on the emotional material and a right-ear advantage for reporting on the verbal material. For the emotional task, the degree of ear asymmetry did not vary significantly as a function of emotional category. Findings indicate the the right hemisphere is specialized for mediating auditory emotional stimuli as early as 5 yrs of age. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional lateralization for auditory temporal processing in male and female rats.

In 3 studies, adult male rats showed significantly better discrimination of tone sequences with the right ear than with the left ear. This result parallels similar findings of left-hemisphere specialization for auditory temporal processing in humans and nonhuman primates. Furthermore, because clinical evidence supports a link between specialization of the left hemisphere for auditory temporal processing and for speech processing, these results may reflect evolutionary precursors to left-hemisphere language specialization. Because male rats showed a stronger ear advantage than female rats, the findings may relate to evidence of a stronger right ear advantage in men than in women. Finally, results suggest that neonatal handling enhances lateralization for auditory temporal processing in both sexes. Combined results implicate neuroendocrine mechanisms as important factors in the development of lateralization for auditory temporal processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)