Hibernoma of the axillary region: a rare benign adipocytic tumor

Hibernoma is a rare benign tumor considered to arise from remnants of fetal brown adipose tissue. It tends to occur in sites where brown fat persists beyond fetal life, such as the interscapular region, but can occur in sites where brown fat is usually absent in adults. Clinicallywell, hibernomas are slow-growing, asymptomatic tumors. However, unlike lipomas, MRI findings sometimes mislead clinicians to diagnose a malignant neoplasm. We describe a 63-year-old male with an axillary hibernoma involving the brachial neurovascular bundles and mimicking a well-differentiated liposarcoma, from which it should be distinguished

Temporal regularity of the environment drives time perception

It’s reasonable to assume that a regularly paced sequence should be perceived as regular, but here we show that perceived regularity depends on the context in which the sequence is embedded. We presented one group of participants with perceptually regularly paced sequences, and another group of participants with mostly irregularly paced sequences (75% irregular, 25% regular). The timing of the final stimulus in each sequence could be varied. In one experiment, we asked whether the last stimulus was regular or not. We found that participants exposed to an irregular environment frequently reported perfectly regularly paced stimuli to be irregular. In a second experiment, we asked participants to judge whether the final stimulus was presented before or after a flash. In this way, we were able to determine distortions in temporal perception as changes in the timing necessary for the sound and the flash to be perceived synchronous. We found that within a regular context, the perceived timing of deviant last stimuli changed so that the relative anisochrony appeared to be perceptually decreased. In the irregular context, the perceived timing of irregular stimuli following a regular sequence was not affected. These observations suggest that humans use temporal expectations to evaluate the regularity of sequences and that expectations are combined with sensory stimuli to adapt perceived timing to follow the statistics of the environment. Expectations can be seen as a-priori probabilities on which perceived timing of stimuli depend

Neural tracking of speech envelope does not unequivocally reflect intelligibility

During listening, brain activity tracks the rhythmic structures of speech signals. Here, we directly dissociated the contribution of neural envelope tracking in the processing of speech acoustic cues from that related to linguistic processing. We examined the neural changes associated with the comprehension of Noise-Vocoded (NV) speech using magnetoencephalography (MEG). Participants listened to NV sentences in a 3-phase training paradigm: (1) pre-training, where NV stimuli were barely comprehended, (2) training with exposure of the original clear version of speech stimulus, and (3) post-training, where the same stimuli gained intelligibility from the training phase. Using this paradigm, we tested if the neural responses of a speech signal was modulated by its intelligibility without any change in its acoustic structure. To test the influence of spectral degradation on neural envelope tracking independently of training, participants listened to two types of NV sentences (4-band and 2-band NV speech), but were only trained to understand 4-band NV speech. Significant changes in neural tracking were observed in the delta range in relation to the acoustic degradation of speech. However, we failed to find a direct effect of intelligibility on the neural tracking of speech envelope in both theta and delta ranges, in both auditory regions-of-interest and whole-brain sensor-space analyses. This suggests that acoustics greatly influence the neural tracking response to speech envelope, and that caution needs to be taken when choosing the control signals for speech-brain tracking analyses, considering that a slight change in acoustic parameters can have strong effects on the neural tracking response

MEG and Language

This text is adapted from MEG and Language by the same authors, submitted to an issue of Neuroimaging Clinics on Magnetoencephalography, edited by Drs. Roland Lee and Mingxiong Huang All authors contributed equally to this work Synopsis We provide an introductory overview of research that uses magnetoencephalography (MEG) to understand the brain basis of human language. The cognitive processes and brain networks that have been implicated in written and spoken language comprehension and production are discussed in relation to different methodologies: we briefly review event-related brain responses, research on the coupling of neural oscillations to speech, oscillatory coupling between brain regions (e.g., auditory-motor coupling), and neural decoding approaches in naturalistic language comprehension. We end with a short section on the clinical relevance of MEG language research, focusing on dyslexia and specific language impairment

Magnetoencephalography and Language

International audienc

Bilateral gamma/delta transcranial alternating current stimulation affects interhemispheric speech sound integration

Perceiving speech requires the integration of different speech cues, that is, formants. When the speech signal is split so that different cues are presented to the right and left ear (dichotic listening), comprehension requires the integration of binaural information. Based on prior electrophysiological evidence, we hypothesized that the integration of dichotically presented speech cues is enabled by interhemispheric phase synchronization between primary and secondary auditory cortex in the gamma frequency band. We tested this hypothesis by applying transcranial alternating current stimulation (TACS) bilaterally above the superior temporal lobe to induce or disrupt interhemispheric gamma-phase coupling. In contrast to initial predictions, we found that gamma TACS applied in-phase above the two hemispheres (interhemispheric lag 0°) perturbs interhemispheric integration of speech cues, possibly because the applied stimulation perturbs an inherent phase lag between the left and right auditory cortex. We also observed this disruptive effect when applying antiphasic delta TACS (interhemispheric lag 180°). We conclude that interhemispheric phase coupling plays a functional role in interhemispheric speech integration. The direction of this effect may depend on the stimulation frequency

The effect of gadolinium-based contrast agents on rat testis

PMID = 2970083