Nonsurgical Treatment of Postpartum Lower Abdominal Skin and Soft-Tissue Laxity Using Microfocused Ultrasound With Visualization.

BACKGROUND: Microfocused ultrasound with visualization (MFU-V) is a well-established treatment modality for skin tightening. There is a paucity of evidence for its use in body treatments, such as the lower abdomen. OBJECTIVE: To investigate the effectiveness and safety of MFU-V in treating lower abdominal skin and soft-tissue laxity in postpartum women. METHODS: The lower abdomen of 20 female patients between 6 and 24 months postpartum are treated with MFU-V using 1.5-, 3.0-, and 4.5-mm transducers. Data are prospectively collected and analyzed at 3 and 6 months using subject-reported and investigator-reported outcome measures. One additional patient underwent planned abdominoplasty 6 weeks after MFU-V treatment with tissue assessed intraoperatively and histologically. RESULTS: There was a mean improvement of 1.0 and 1.3 grades at 6 months using the investigator-reported and patient-reported skin laxity scale, respectively (p < .001). Patient-reported outcomes and satisfaction survey showed consistent improvement at 6 months. Histological examination of pretreated tissue showed increased total collagen, increased number and thickness of fibrous septae, and no change in fat cells within pretreated tissue compared with the control. No significant adverse events were recorded. CONCLUSION: MFU-V is an effective and safe treatment modality for lower abdominal skin laxity in postpartum patients.

Behavioral relevance helps untangle natural vocal categories in a specific subset of core auditory cortical pyramidal neurons.

Sound categorization is essential for auditory behaviors like acoustic communication, but its genesis within the auditory pathway is not well understood-especially for learned natural categories like vocalizations, which often share overlapping acoustic features that must be distinguished (e.g., speech). We use electrophysiological mapping and single-unit recordings in mice to investigate how representations of natural vocal categories within core auditory cortex are modulated when one category acquires enhanced behavioral relevance. Taking advantage of a maternal mouse model of acoustic communication, we found no long-term auditory cortical map expansion to represent a behaviorally relevant pup vocalization category-contrary to expectations from the cortical plasticity literature on conditioning with pure tones. Instead, we observed plasticity that improved the separation between acoustically similar pup and adult vocalization categories among a physiologically defined subset of late-onset, putative pyramidal neurons, but not among putative interneurons. Additionally, a larger proportion of these putative pyramidal neurons in maternal animals compared with nonmaternal animals responded to the individual pup call exemplars having combinations of acoustic features most typical of that category. Together, these data suggest that higher-order representations of acoustic categories arise from a subset of core auditory cortical pyramidal neurons that become biased toward the combination of acoustic features statistically predictive of membership to a behaviorally relevant sound category.

Subset of thin spike cortical neurons preserve the peripheral encoding of stimulus onsets.

An important question in auditory neuroscience concerns how the neural representation of sound features changes from the periphery to the cortex. Here we focused on the encoding of sound onsets and we used a modeling approach to explore the degree to which auditory cortical neurons follow a similar envelope integration mechanism found at the auditory periphery. Our "forward" model was able to predict relatively accurately the timing of first spikes evoked by natural communication calls in the auditory cortex of awake, head-restrained mice, but only for a subset of cortical neurons. These neurons were systematically different in their encoding of the calls, exhibiting less call selectivity, shorter latency, greater precision, and more transient spiking compared with the same factors of their poorly predicted counterparts. Importantly, neurons that fell into this best-predicted group all had thin spike waveforms, suggestive of suspected interneurons conveying feedforward inhibition. Indeed, our population of call-excited thin spike neurons had significantly higher spontaneous rates and larger frequency tuning bandwidths than those of thick spike neurons. Thus the fidelity of our model's first spike predictions segregated neurons into one earlier responding subset, potentially dominated by suspected interneurons, which preserved a peripheral mechanism for encoding sound onsets and another longer latency subset that reflected higher, likely centrally constructed nonlinearities. These results therefore provide support for the hypothesis that physiologically distinct subclasses of neurons in the auditory cortex may contribute hierarchically to the representation of natural stimuli.

Inhibitory plasticity in a lateral band improves cortical detection of natural vocalizations.

The interplay between excitation and inhibition in the auditory cortex is crucial for the processing of acoustic stimuli. However, the precise role that inhibition plays in the distributed cortical encoding of natural vocalizations has not been well studied. We recorded single units (SUs) and local field potentials (LFPs) in the awake mouse auditory cortex while presenting pup isolation calls to animals that either do (mothers) or do not (virgins) recognize the sounds as behaviorally relevant. In both groups, we observed substantial call-evoked inhibition. However, in mothers this was earlier, longer, stronger, and more stereotyped compared to virgins. This difference was most apparent for recording sites tuned to tone frequencies lower than the pup calls' high-ultrasonic frequency range. We hypothesize that this auditory cortical inhibitory plasticity improves pup call detection in a relatively specific manner by increasing the contrast between call-evoked responses arising from high-ultrasonic and lateral frequency neural populations.