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Interactive Specialization: A domain-general framework for human functional brain development?

A domain-general framework for interpreting data on human functional brain development is presented. Assumptions underlying the general theory and predictions derived from it are discussed. Developmental functional neuroimaging data from the domains of face processing, social cognition, word learning and reading, executive control, and brain resting states are used to assess these predictions. Finally, potential criticisms of the framework are addressed and challenges for the future presented.

from Developmental Cognitive Neuroscience

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Temporal changes in vocal functions of human scarred vocal folds after cordectomy

Some individual variation was observed in the temporal changes of vocal function of scarred vocal folds after cordectomy. However, in terms of vibratory and aerodynamic functions, this study suggests that it takes at least 6 months for maturation of vocal fold scarring. Laryngoscope, 2010

from The Laryngoscope

Latencies of Auditory Steady-State Responses Recorded in Early Infancy

Multiple-stimulus auditory steady-state responses (ASSRs) were assessed in 111 ears of 70 infants between -4 and 19 weeks of age at risk for hearing loss. ASSR thresholds obtained in infants with normal hearing (n = 69 ears) were compared with normal adult ASSR thresholds (n = 32 ears), and the linear relation between ASSR thresholds and behavioral thresholds (BHTs) was investigated in normal-hearing and hearing-impaired infants (n = 79 ears). Furthermore, latency estimates of significant responses to stimuli of 50 dB SPL were compared between the normal-hearing infants (n = 171 data points) and adults (n = 124 data points) and developmental changes in latency were evaluated within the infant group. Normal ASSR thresholds were on average 12 dB higher in infants compared with adults. Correlations between ASSR thresholds and BHTs were 0.75, 0.87, 0.87 and 0.79 for 500, 1000, 2000 and 4000 Hz, respectively. There was a significant effect of carrier frequency on ASSR latency, with higher carrier frequencies evoking shorter latencies in both infants and adults. Mean latencies in adults were 24.3 ± 1.5, 22.3 ± 1.1, 19.4 ± 1.0 and 18.0 ± 1.1 ms for 500, 1000, 2000 and 4000 Hz, respectively. Depending on the data fit of the infant latency estimates, mean latencies were 1.0 ms shorter or 9.5 ms longer in infants compared with adults. In infants, latencies were on average 2.0 ms longer in the youngest infant group (0 weeks) relative to the oldest infant group (3-8 weeks). These age-related trends, together with other arguments, point to longer latencies in infants compared with adults. The results of this study are valuable as a clinical reference for interpreting ASSR results obtained in high-risk infants within their first months of life and indicate that developmental changes occur regarding ASSR latency.

from Audiology & Neuro-Otology

Latencies of Auditory Steady-State Responses Recorded in Early Infancy

Multiple-stimulus auditory steady-state responses (ASSRs) were assessed in 111 ears of 70 infants between -4 and 19 weeks of age at risk for hearing loss. ASSR thresholds obtained in infants with normal hearing (n = 69 ears) were compared with normal adult ASSR thresholds (n = 32 ears), and the linear relation between ASSR thresholds and behavioral thresholds (BHTs) was investigated in normal-hearing and hearing-impaired infants (n = 79 ears). Furthermore, latency estimates of significant responses to stimuli of 50 dB SPL were compared between the normal-hearing infants (n = 171 data points) and adults (n = 124 data points) and developmental changes in latency were evaluated within the infant group. Normal ASSR thresholds were on average 12 dB higher in infants compared with adults. Correlations between ASSR thresholds and BHTs were 0.75, 0.87, 0.87 and 0.79 for 500, 1000, 2000 and 4000 Hz, respectively. There was a significant effect of carrier frequency on ASSR latency, with higher carrier frequencies evoking shorter latencies in both infants and adults. Mean latencies in adults were 24.3 ± 1.5, 22.3 ± 1.1, 19.4 ± 1.0 and 18.0 ± 1.1 ms for 500, 1000, 2000 and 4000 Hz, respectively. Depending on the data fit of the infant latency estimates, mean latencies were 1.0 ms shorter or 9.5 ms longer in infants compared with adults. In infants, latencies were on average 2.0 ms longer in the youngest infant group (0 weeks) relative to the oldest infant group (3-8 weeks). These age-related trends, together with other arguments, point to longer latencies in infants compared with adults. The results of this study are valuable as a clinical reference for interpreting ASSR results obtained in high-risk infants within their first months of life and indicate that developmental changes occur regarding ASSR latency.

from Audiology & Neuro-Otology

Spatiotemporal Patterns of Cortical Activity with Bilateral Cochlear Implants in Congenital Deafness

Congenital deafness affects developmental processes in the auditory cortex. In this study, local field potentials (LFPs) were mapped at the cortical surface with microelectrodes in response to cochlear implant stimulation. LFPs were compared between hearing controls and congenitally deaf cats (CDCs). Pulsatile electrical stimulation initially evoked cortical activity in the rostral parts of the primary auditory field (A1). This progressed both in the approximate dorsoventral direction (along the isofrequency stripe) and in the rostrocaudal direction. The dorsal branch of the wavefront split into a caudal branch (propagating in A1) and another smaller one propagating rostrally into the AAF (anterior auditory field). After the front reached the caudal border of A1, a “reflection wave” appeared, propagating back rostrally. In total, the waves took 13–15 ms to propagate along A1 and return back. In CDCs, the propagation pattern was significantly disturbed, with a more synchronous activation of distant cortical regions. The maps obtained from contralateral and ipsilateral stimulation overlapped in both groups of animals. Although controls showed differences in the latency–amplitude patterns, cortical waves evoked by contralateral and ipsilateral stimulation were more similar in CDCs. Additionally, in controls, LFPs with contralateral and ipsilateral stimulation were more similar in caudal A1 than in rostral A1. This dichotomy was lost in deaf animals. In conclusion, propagating cortical waves are specific for the contralateral ear, they are affected by auditory deprivation, and the specificity of the cortex for stimulation of the contralateral ear is reduced by deprivation.

from the Journal of Neuroscience

The representation of voice onset time in the cortical auditory evoked potentials of young children

Our results demonstrate that a representation of VOT, as recorded by scalp electrodes, exists in the developing cortical evoked response, but that representation is different than that in the adult response. The results describe the developmental changes in cortical representation of VOT in children ages 2–8 years.

Significance
The child’s CAEP reflects physiologic processes, which are involved in the cortical encoding of VOT. Overall, cortical representation of VOT in children ages 2–8 is different than in adults.

from Clinical Neurophysiology

Maturation of Visual and Auditory Temporal Processing in School-Aged Children

from the Journal of Speech, Language, and Hearing Research

Purpose: To examine development of sensitivity to auditory and visual temporal processes in children and the association with standardized measures of auditory processing and communication.

Methods: Normative data on tests of visual and auditory processing were collected on 18 adults and 98 children aged 6–10 years of age. Auditory processes included detection of pitch from temporal cues using iterated rippled noise and frequency modulation detection at 2 Hz, 40 Hz, and 240 Hz. Visual processes were coherent form and coherent motion detection. Test–retest data were gathered on 21 children.

Results: Performance on perceptual tasks improved with age, except for fine temporal processing (iterated rippled noise) and coherent form perception, both of which were relatively stable over the age range. Within-subject variability (as assessed by track width) did not account for age-related change. There was no evidence for a common temporal processing factor, and there were no significant associations between perceptual task performance and communication level (Children’s Communication Checklist, 2nd ed.; D. V. M. Bishop, 2003) or speech-based auditory processing (SCAN-C; R. W. Keith, 2000).

Conclusions: The auditory tasks had different developmental trajectories despite a common procedure, indicating that age-related change was not solely due to responsiveness to task demands. The 2-Hz frequency modulation detection task, previously used in dyslexia research, and the visual tasks had low reliability compared to other measures.