Anatomical differences in the human inferior colliculus relate to the perceived valence of musical consonance and dissonance.

Helmholtz himself speculated about a role of the cochlea in the perception of musical dissonance. Here we indirectly investigated this issue, assessing the valence judgment of musical stimuli with variable consonance/dissonance and presented diotically (exactly the same dissonant signal was presented to both ears) or dichotically (a consonant signal was presented to each ear--both consonant signals were rhythmically identical but differed by a semitone in pitch). Differences in brain organisation underlying inter-subject differences in the percept of dichotically presented dissonance were determined with voxel-based morphometry. Behavioral results showed that diotic dissonant stimuli were perceived as more unpleasant than dichotically presented dissonance, indicating that interactions within the cochlea modulated the valence percept during dissonance. However, the behavioral data also suggested that the dissonance percept did not depend crucially on the cochlea, but also occurred as a result of binaural integration when listening to dichotic dissonance. These results also showed substantial between-participant variations in the valence response to dichotic dissonance. These differences were in a voxel-based morphometry analysis related to differences in gray matter density in the inferior colliculus, which strongly substantiated a key role of the inferior colliculus in consonance/dissonance representation in humans.

Acoustocerebrography in septic patients: A randomized and controlled pilot study.

Sepsis-associated encephalopathy (SAE) is a common organ dysfunction in patients with severe sepsis or septic shock and leads to higher mortality and longer hospital stay. The diagnosis remains an exclusion process; none of the available measurements are specific for SAE. The aim of the presented prospective and controlled clinical study was to evaluate the possible role of molecular acoustics in determining acute brain injury in septic patients using an acoustocerebrography (ACG) system. ACG is a multifrequency, transcranial ultrasound method that measures the attenuation and time of flight to detect changes in the brain tissue. After approval from the local research ethics committee (of the University Hospital of Rostock: Reg. No.: A 2016-0026), 20 patients were included in two study groups: septic shock group (SG) and control group (CG; postoperative nonseptic patients). All patients were screened several times with the ACG on different days. Blood parameters of organ function, sepsis-related organ failure assessment score, and delirium scores [Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) and Intensive Care Delirium Screening Checklist (ICDSC)] were obtained as well. A neurologist examined all patients at inclusion. Predictive analysis was done using a data-driven statistical method and by deriving a parameter from the ACG data. The study was registered under "clinicaltrials.gov" (Reg. No.: NCT03173196). All patients in the SG were CAM-ICU-positive at inclusion (ICDSC: in mean 4.0) and had clinical signs of SAE. In contrast, all patients in the CG were CAM-ICU-negative, with an ICDSC score of 0. Predictive analysis using the ACG data presented an accuracy of 83.4% with a specificity of 89.0% and a sensitivity of 75.1%. The ACG method may be helpful for the monitoring and diagnosing acute brain injury; however, the results of this first report should be verified by further clinical studies. Further investigations should include long-established instruments of SAE diagnosis, e.g., electroencephalography, MRI, and biomarkers, to compare the results with the ACG measurements.

From understanding to appreciating music cross-culturally.

It has long been debated which aspects of music perception are universal and which are developed only after exposure to a specific musical culture. Here we investigated whether "iconic" meaning in Western music, emerging from musical information resembling qualities of objects, or qualities of abstract concepts, can be recognized cross-culturally. To this end we acquired a profile of semantic associations (such as, for example, fight, river, etc.) to Western musical pieces from each participant, and then compared these profiles across cultural groups. Results show that the association profiles between Mafa, an ethnic group from northern Cameroon, and Western listeners are different, but that the Mafa have a consistent association profile, indicating that their associations are strongly informed by their enculturation. Results also show that listeners for whom Western music is novel, but whose association profile was more similar to the mean Western music association profile also had a greater appreciation of the Western music. The data thus show that, to some degree, iconic meaning transcends cultural boundaries, with a high inter-individual variance, probably because meaning in music is prone to be overwritten by individual and cultural experience.