The ability to detect and rapidly process harmonic sounds, which in nature are typical of animal vocalizations and speech, can be critical for communication among conspecifics and for survival. Single-unit studies have reported neurons in auditory cortex sensitive to specific combinations of frequencies (e.g., harmonics), theorized to rapidly abstract or filter for specific structures of incoming sounds, where large ensembles of such neurons may constitute spectral templates. We studied the contribution of harmonic structure to activation of putative spectral templates in human auditory cortex by using a wide variety of animal vocalizations, as well as artificially constructed iterated rippled noises (IRNs). Both the IRNs and vocalization sounds were quantitatively characterized by calculating a global harmonics-to-noise ratio (HNR). Using functional MRI, we identified HNR-sensitive regions when presenting either artificial IRNs and/or recordings of natural animal vocalizations. This activation included regions situated between functionally defined primary auditory cortices and regions preferential for processing human nonverbal vocalizations or speech sounds. These results demonstrate that the HNR of sound reflects an important second-order acoustic signal attribute that parametrically activates distinct pathways of human auditory cortex. Thus, these results provide novel support for the presence of spectral templates, which may subserve a major role in the hierarchical processing of vocalizations as a distinct category of behaviorally relevant sound.

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From 2010 to 2019, 40.5% fewer senior students from United States (US) allopathic medical schools pursued pathology in the Main Residency Match. To possibly explain this trend, we sought to identify major concerns about pathology which were made during this time. Because the Student Doctor Network (SDN) website is widely used by students at American medical schools during the residency application process, SDN has been shown to influence career decisions. So, the 50 all-time most-viewed SDN pathology threads (as of February 2018) were analyzed. The words "job" and "jobs" were used in the title of 11 of the 50 (22%) threads, which altogether received more than 400,000 views. However, the term "job(s)" was rarely used by 14 other major medical specialties. Seven of the 11 (63.6%) job-related threads were created from 2009 to 2011, corresponding with the start of the decline in medical students pursuing pathology residency. It was reasoned that job-market concerns within SDN threads may have discouraged students from pursuing pathology. To test this hypothesis, 5 pathology residents were asked to read all 11 threads and then complete a survey. Most thread reviewers agreed that commenters, which included medical students, were concerned about the pathology job-market and that medical students who viewed the threads would be less likely to pursue pathology residency. Because more than 85% of SDN users are from the US, the threads likely had a greater impact on American medical students compared to foreign students. In conclusion, job-market concerns over the past decade are so prominent in the SDN pathology forum that they likely contributed to fewer seniors from US allopathic medical schools pursuing pathology residency. As of 2019, there are 12 job-related threads among the 50 all-time most-viewed, including threads created in 2016 and 2017. To improve recruitment, the pathology community should carefully review and address concerns about employment opportunities. Due to conflicting reports, additional studies are needed to determine if a mismatch in workforce supply and demand warrants prompt and thoughtful intervention.