Blog Archives
Distraction task rather than focal attention modulates gamma activity associated with auditory steady-state responses (ASSRs)
Conclusions
The phase-locked measures of 40Hz ASSR are attenuated when attention to the stimulation is low, i.e. the subject is effortfully focused on the competitive “distraction” task performance. Lower arousal level increases the total intensity of 40Hz ASSRs.
Distraction task rather than focal attention modulates gamma activity associated with auditory steady-state responses (ASSRs)
Conclusions
The phase-locked measures of 40Hz ASSR are attenuated when attention to the stimulation is low, i.e. the subject is effortfully focused on the competitive “distraction” task performance. Lower arousal level increases the total intensity of 40Hz ASSRs.
Comparison of auditory electrophysiological responses in normal-hearing patients with and without tinnitus
Conclusion: The pathogenesis and optimum management of tinnitus are still unclear. It often occurs with primary ear disease, usually associated with hearing loss, but may occur in patients with normal hearing. Observed changes in auditory brainstem and middle latency responses indicate central auditory alterations. Tinnitus involves both peripheral and central activity, and complete audiological and neurophysiological investigation is required. Management should be based on both audiological and neurophysiological findings.
from the Journal of Laryngology and Otology
Functional ear (a)symmetry in brainstem neural activity relevant to encoding of voice pitch: A precursor for hemispheric specialization?
Pitch processing is lateralized to the right hemisphere; linguistic pitch is further mediated by left cortical areas. This experiment investigates whether ear asymmetries vary in brainstem representation of pitch depending on linguistic status. Brainstem frequency-following responses (FFRs) were elicited by monaural stimulation of the left and right ear of 15 native speakers of Mandarin Chinese using two synthetic speech stimuli that differ in linguistic status of tone. One represented a native lexical tone (Tone 2: T2); the other, T2′, a nonnative variant in which the pitch contour was a mirror image of T2 with the same starting and ending frequencies. Two 40-ms portions of f0 contours were selected in order to compare two regions (R1, early; R2 late) differing in pitch acceleration rate and perceptual saliency. In R2, linguistic status effects revealed that T2 exhibited a larger degree of FFR rightward ear asymmetry as reflected in f0 amplitude relative to T2′. Relative to midline (ear asymmetry = 0), the only ear asymmetry reaching significance was that favoring left ear stimulation elicited by T2′. By left- and right-ear stimulation separately, FFRs elicited by T2 were larger than T2′ in the right ear only. Within T2′, FFRs elicited by the earlier region were larger than the later in both ears. Within T2, no significant differences in FFRS were observed between regions in either ear. Collectively, these findings support the idea that origins of cortical processing preferences for perceptually-salient portions of pitch are rooted in early, preattentive stages of processing in the brainstem.
from Brain and Language
Auditory-Motor Expertise Alters “Speech Selectivity” in Professional Musicians and Actors
Several perisylvian brain regions show preferential activation for spoken language above and beyond other complex sounds. These “speech-selective” effects might be driven by regions’ intrinsic biases for processing the acoustical or informational properties of speech. Alternatively, such speech selectivity might emerge through extensive experience in perceiving and producing speech sounds. This functional magnetic resonance imaging (fMRI) study disambiguated such audiomotor expertise from speech selectivity by comparing activation for listening to speech and music in female professional violinists and actors. Audiomotor expertise effects were identified in several right and left superior temporal regions that responded to speech in all participants and music in violinists more than actresses. Regions associated with the acoustic/information content of speech were identified along the entire length of the superior temporal sulci bilaterally where activation was greater for speech than music in all participants. Finally, an effect of performing arts training was identified in bilateral premotor regions commonly activated by finger and mouth movements as well as in right hemisphere “language regions.” These results distinguish the seemingly speech-specific neural responses that can be abolished and even reversed by long-term audiomotor experience.
from Cerebral Cortex
Cortical organization of environmental sounds by attribute
Semantic knowledge is supported by a widely distributed neuronal network, with differential patterns of activation depending upon experimental stimulus or task demands. Despite a wide body of knowledge on semantic object processing from the visual modality, the response of this semantic network to environmental sounds remains relatively unknown. Here, we used fMRI to investigate how access to different conceptual attributes from environmental sound input modulates this semantic network. Using a range of living and manmade sounds, we scanned participants whilst they carried out an object attribute verification task. Specifically, we tested visual perceptual, encyclopedic, and categorical attributes about living and manmade objects relative to a high-level auditory perceptual baseline to investigate the differential patterns of response to these contrasting types of object-related attributes, whilst keeping stimulus input constant across conditions. Within the bilateral distributed network engaged for processing environmental sounds across all conditions, we report here a highly significant dissociation within the left hemisphere between the processing of visual perceptual and encyclopedic attributes of objects.
from Human Brain Mapping
Brainstem auditory evoked potential with speech stimulus
CONCLUSION: based on the gathered data it can be observed that this potential works as a new tool for understanding the encoding of sound at the brainstem level.
Improving digit span assessment of short-term verbal memory
We measured digit span (DS) in two experiments that used computerized presentation of randomized auditory digits with performance-adapted list length adjustment. A new mean span (MS) metric of DS was developed that showed reduced variance, improved test-retest reliability, and higher correlations with the results of other neuropsychological test results when compared to traditional DS measures. The MS metric also enhanced the sensitivity of forward versus backward span comparisons, enabled the development of normative performance criteria with subdigit precision, and elucidated changes in DS performance with age and education level. Computerized stimulus delivery and improved scoring metrics significantly enhance the precision of DS assessments of short-term verbal memory.
from the Journal of Clinical and Experimental Neuropsychology
Distributed processing and cortical specialization for speech and environmental sounds in human temporal cortex
Using functional MRI, we investigated whether auditory processing of both speech and meaningful non-linguistic environmental sounds in superior and middle temporal cortex relies on a complex and spatially distributed neural system. We found that evidence for spatially distributed processing of speech and environmental sounds in a substantial extent of temporal cortices. Most importantly, regions previously reported as selective for speech over environmental sounds also contained distributed information. The results indicate that temporal cortices supporting complex auditory processing, including regions previously described as speech-selective, are in fact highly heterogeneous.
from Brain and Language
Maturation of auditory function related to hearing threshold estimations using the auditory brainstem response during infancy
The maturation of the ABR should be considered during the estimation of an infant’s audiogram and subsequent diagnosis.
from the International Journal of Pediatric Otorhinolaryngology
Effect of task-irrelevant high-speed verbal stimulation on a visual/verbal word-discrimination task: An event-related potential study
Conclusions
We considered that high-speed speech stimulation was processed without conscious comprehension and competed with verbal processing during the visual-word-discrimination task, possibly by interfering with the use of WM.