An electroencephalographic examination of the autonomous sensory meridian response (ASMR).

Autonomous sensory meridian response (ASMR) is a perceptual phenomenon characterized by pleasurable tingling sensations in the head and neck, as well as pleasurable feelings of relaxation, that reliably arise while attending to a specific triggering stimulus (e.g., whispering or tapping sounds). Currently, little is known about the neutral substrates underlying these experiences. In this study, 14 participants who experience ASMR, along with 14 control participants, were presented with four video stimuli and four auditory stimuli. Half of these stimuli were designed to elicit ASMR and half were non-ASMR control stimuli. Brain activity was measured using a 32-channel EEG system. The results indicated that ASMR stimuli-particularly auditory stimuli-elicited increased alpha wave activity in participants with self-reported ASMR, but not in matched control participants. Similar increases were also observed in frequency bands associated with movement (gamma waves and sensorimotor rhythm). These results are consistent with the reported phenomenology of ASMR, which involves both attentional and sensorimotor characteristics.

Theta-gamma coupling reflects the interaction of bottom-up and top-down processes in speech perception in children.

This study investigates how the interaction of different brain oscillations (particularly theta-gamma coupling) modulates the bottom-up and top-down processes during speech perception. We employed a speech perception paradigm that manipulated the congruency between a visually presented picture and an auditory stimulus and asked participants to judge whether they matched or mismatched. A group of children (mean age 10 years, 5 months) participated in this study and their electroencephalographic (EEG) data were recorded while performing the experimental task. It was found that in comparison with mismatch condition, match condition facilitated speech perception by eliciting greater theta-gamma coupling in the frontal area and smaller theta-gamma coupling in the left temporal area. These findings suggested that a top-down facilitation effect from congruent visual pictures engaged different mechanisms in low-level sensory (temporal) regions and high-level linguistic and decision (frontal) regions. Interestingly, hemispheric asymmetry is with higher theta-gamma coupling in the match condition in the right hemisphere and higher theta-gamma coupling in the mismatch condition in the left hemisphere. This indicates that a fast global processing strategy and a slow detailed processing strategy were differentially adopted in the match and mismatch conditions. This study provides new insight into the mechanisms of speech perception from the interaction of different oscillatory activities and provides neural evidence for theories of speech perception allowing for top-down feedback connections. Furthermore, it sheds light on children's speech perception development by showing a similar pattern of integration of bottom-up and top-down information during speech perception as previous studies have revealed in adults.

ERPs reveal the temporal dynamics of auditory word recognition in specific language impairment.

We used event-related potentials (ERPs) to compare auditory word recognition in children with specific language impairment (SLI group; N=14) to a group of typically developing children (TD group; N=14). Subjects were presented with pictures of items and heard auditory words that either matched or mismatched the pictures. Mismatches overlapped expected words in word-onset (cohort mismatches; see: DOLL, hear: dog), rhyme (CONE -bone), or were unrelated (SHELL -mug). In match trials, the SLI group showed a different pattern of N100 responses to auditory stimuli compared to the TD group, indicative of early auditory processing differences in SLI. However, the phonological mapping negativity (PMN) response to mismatching items was comparable across groups, suggesting that just like TD children, children with SLI are capable of establishing phonological expectations and detecting violations of these expectations in an online fashion. Perhaps most importantly, we observed a lack of attenuation of the N400 for rhyming words in the SLI group, which suggests that either these children were not as sensitive to rhyme similarity as their typically developing peers, or did not suppress lexical alternatives to the same extent. These findings help shed light on the underlying deficits responsible for SLI.

Electrophysiological indices of phonological impairments in dyslexia.

PURPOSE: A range of studies have shown difficulties in perceiving acoustic and phonetic information in dyslexia; however, much less is known about how such difficulties relate to the perception of individual words. The authors present data from event-related potentials (ERPs) examining the hypothesis that children with dyslexia have difficulties with processing phonemic information within spoken words compared to age-matched readers with typical development. METHOD: The authors monitored ERPs to auditory words during a simple picture-word matching task. The key manipulation was the inclusion of both matching stimuli and three types of mismatches (cohort, CONE-comb; rhyme, CONE-bone; and unrelated, CONE-fox). RESULTS: Children with dyslexia showed atypical N400 ERP waveforms to both types of phonological mismatches, but not to phonologically unrelated mismatches, reflecting a relative insensitivity to phonological overlap among auditory words. CONCLUSION: The data suggest that children with dyslexia have impairments in integrating phonological information into word-level representations. The results suggest that speech perception difficulties in dyslexia might have consequences for processing auditory words.

Distinct representations of subtraction and multiplication in the neural systems for numerosity and language.

It has been proposed that recent cultural inventions such as symbolic arithmetic recycle evolutionary older neural mechanisms. A central assumption of this hypothesis is that the degree to which a preexisting mechanism is recycled depends on the degree of similarity between its initial function and the novel task. To test this assumption, we investigated whether the brain region involved in magnitude comparison in the intraparietal sulcus (IPS), localized by a numerosity comparison task, is recruited to a greater degree by arithmetic problems that involve number comparison (single-digit subtractions) than by problems that involve retrieving number facts from memory (single-digit multiplications). Our results confirmed that subtractions are associated with greater activity in the IPS than multiplications, whereas multiplications elicit greater activity than subtractions in regions involved in verbal processing including the middle temporal gyrus (MTG) and inferior frontal gyrus (IFG) that were localized by a phonological processing task. Pattern analyses further indicated that the neural mechanisms more active for subtraction than multiplication in the IPS overlap with those involved in numerosity comparison and that the strength of this overlap predicts interindividual performance in the subtraction task. These findings provide novel evidence that elementary arithmetic relies on the cooption of evolutionary older neural circuits.

Investigating the time course of spoken word recognition: electrophysiological evidence for the influences of phonological similarity.

Behavioral and modeling evidence suggests that words compete for recognition during auditory word identification, and that phonological similarity is a driving factor in this competition. The present study used event-related potentials (ERPs) to examine the temporal dynamics of different types of phonological competition (i.e., cohort and rhyme). ERPs were recorded during a novel picture-word matching task, where a target picture was followed by an auditory word that either matched the target (CONE-cone), or mismatched in one of three ways: rhyme (CONE-bone), cohort (CONE-comb), and unrelated (CONE-fox). Rhymes and cohorts differentially modulated two distinct ERP components, the phonological mismatch negativity and the N400, revealing the influences of prelexical and lexical processing components in speech recognition. Cohort mismatches resulted in late increased negativity in the N400, reflecting disambiguation of the later point of miscue and the combined influences of top-down expectations and misleading bottom-up phonological information on processing. In contrast, we observed a reduction in the N400 for rhyme mismatches, reflecting lexical activation of rhyme competitors. Moreover, the observed rhyme effects suggest that there is an interaction between phoneme-level and lexical-level information in the recognition of spoken words. The results support the theory that both levels of information are engaged in parallel during auditory word recognition in a way that permits both bottom-up and top-down competition effects.