Search results for "auditory cortex"
showing 10 items of 85 documents
The neural basis of sublexical speech and corresponding nonspeech processing: a combined EEG-MEG study.
2014
Abstract We addressed the neural organization of speech versus nonspeech sound processing by investigating preattentive cortical auditory processing of changes in five features of a consonant–vowel syllable (consonant, vowel, sound duration, frequency, and intensity) and their acoustically matched nonspeech counterparts in a simultaneous EEG–MEG recording of mismatch negativity (MMN/MMNm). Overall, speech–sound processing was enhanced compared to nonspeech sound processing. This effect was strongest for changes which affect word meaning (consonant, vowel, and vowel duration) in the left and for the vowel identity change in the right hemisphere also. Furthermore, in the right hemisphere, spe…
Electrophysiological evidence for change detection in speech sound patterns by anesthetized rats
2014
Human infants are able to detect changes in grammatical rules in a speech sound stream. Here, we tested whether rats have a comparable ability by using an electrophysiological measure that has been shown to reflect higher order auditory cognition even before it becomes manifested in behavioral level. Urethane-anesthetized rats were presented with a stream of sequences consisting of three pseudowords carried out at a fast pace. Frequently presented “standard” sequences had 16 variants which all had the same structure. They were occasionally replaced by acoustically novel “deviant” sequences of two different types: structurally consistent and inconsistent sequences. Two stimulus conditions we…
Age-related changes of NADPH-diaphorase-positive neurons in the rat inferior colliculus and auditory cortex
2007
Nitric oxide (NO) has been implied in age-related changes of the central nervous system (CNS) and the central auditory pathway. The present study was conducted to investigate whether the number of NO-producing cells and their morphometric characteristics in the inferior colliculus (IC) and the auditory cortex (AC) are changed with the increasing age of the subjects. IC and AC sections of adult and senile Wistar rats were studied using the histochemical detection of NADPH-diaphorase activity (NADPH-d), a marker for neurons containing nitric oxide synthase (NOS). Our results showed a decreased area of the somas of NADPH-d-positive neurons in the dorsal cortex (DC) of the IC and a diffuse loss…
Oscillatory Dynamics Underlying Perceptual Narrowing of Native Phoneme Mapping from 6 to 12 Months of Age
2016
During the first months of life, human infants process phonemic elements from all languages similarly. However, by 12 months of age, as language-specific phonemic maps are established, infants respond preferentially to their native language. This process, known as perceptual narrowing, supports neural representation and thus efficient processing of the distinctive phonemes within the sound environment. Although oscillatory mechanisms underlying processing of native and non-native phonemic contrasts were recently delineated in 6-month-old infants, the maturational trajectory of these mechanisms remained unclear. A group of typically developing infants born into monolingual English families, …
Change detection to tone pairs during the first year of life – Predictive longitudinal relationships for EEG-based source and time-frequency measures
2019
Abstract Brain responses related to auditory processing show large changes throughout infancy and childhood with some evidence that the two hemispheres might mature at different rates. Differing rates of hemispheric maturation could be linked to the proposed functional specialization of the hemispheres in which the left auditory cortex engages in analysis of precise timing information whereas the right auditory cortex focuses on analysis of sound frequency. Here the auditory change detection process for rapidly presented tone-pairs was examined in a longitudinal sample of infants at the age of 6 and 12 months using EEG. The ERP response related to change detection of a frequency contrast, i…
Cortical processing of musical sounds in children with Cochlear Implants
2012
Abstract Objective We studied the neurocognitive mechanisms of musical instrument sound perception in children with Cochlear Implants (CIs) and in children with normal hearing (NH). Methods ERPs were recorded in a new multi-feature change-detection paradigm. Three magnitudes of change in fundamental frequency, musical instrument, duration, intensity increments and decrements, and presence of a temporal gap were presented amongst repeating 295 Hz piano tones. Independent Component Analysis was utilized to remove artifacts caused by the Cochlear Implants. Results The ERPs were similar in the two groups across all perceptual dimensions except for intensity increment deviants. CI children had s…
Reading skill and neural processing accuracy improvement after a 3-hour intervention in preschoolers with difficulties in reading-related skills
2012
This study aimed at determining whether an intervention game developed for strengthening phonological awareness has a remediating effect on reading skills and central auditory processing in 6-year-old preschool children with difficulties in reading-related skills. After a 3-hour training only, these children made a greater progress in reading-related skills than did their matched controls who did mathematical exercises following comparable training format. Furthermore, the results suggest that this brief intervention might be beneficial in modulating the neural basis of phonetic discrimination as an enhanced speech-elicited mismatch negativity (MMN) was seen in the intervention group, indic…
Memory-Based Mismatch Response to Frequency Changes in Rats
2011
Any occasional changes in the acoustic environment are of potential importance for survival. In humans, the preattentive detection of such changes generates the mismatch negativity (MMN) component of event-related brain potentials. MMN is elicited to rare changes (‘deviants’) in a series of otherwise regularly repeating stimuli (‘standards’). Deviant stimuli are detected on the basis of a neural comparison process between the input from the current stimulus and the sensory memory trace of the standard stimuli. It is, however, unclear to what extent animals show a similar comparison process in response to auditory changes. To resolve this issue, epidural potentials were recorded above the pr…
Abnormal synchrony and effective connectivity in patients with schizophrenia and auditory hallucinations
2014
Auditory hallucinations (AH) are the most frequent positive symptoms in patients with schizophrenia. Hallucinations have been related to emotional processing disturbances, altered functional connectivity and effective connectivity deficits. Previously, we observed that, compared to healthy controls, the limbic network responses of patients with auditory hallucinations differed when the subjects were listening to emotionally charged words. We aimed to compare the synchrony patterns and effective connectivity of task-related networks between schizophrenia patients with and without AH and healthy controls. Schizophrenia patients with AH (n = 27) and without AH (n = 14) were compared with healt…
Abnormal functioning of the left temporal lobe in language-impaired children
2014
Specific language impairment is associated with enduring problems in language-related functions. We followed the spatiotemporal course of cortical activation in SLI using magnetoencephalography. In the experiment, children with normal and impaired language development heard spoken real words and pseudowords presented only once or two times in a row. In typically developing children, the activation in the bilateral superior temporal cortices was attenuated to the second presentation of the same word. In SLI children, this repetition effect was nearly nonexistent in the left hemisphere. Furthermore, the activation was equally strong to words and pseudowords in SLI children whereas in the typi…