Variation in the Meaning of Alarm Calls in Verreaux’s and Coquerel’s Sifakas (Propithecus verreauxi, P. coquereli)

The comprehension and usage of primate alarm calls appear to be influenced by social learning. Thus, alarm calls provide flexible behavioral mechanisms that may allow animals to develop appropriate responses to locally present predators. To study this potential flexibility, we compared the usage and function of 3 alarm calls common to 2 closely related sifaka species (Propithecus verreauxi and P. coquereli), in each of 2 different populations with different sets of predators. Playback studies revealed that both species in both of their respective populations emitted roaring barks in response to raptors, and playbacks of this call elicited a specific anti-raptor response (look up and climb down). However, in Verreaux’s sifakas, tchi-faks elicited anti-terrestrial predator responses (look down, climb up) in the population with a higher potential predation threat by terrestrial predators, whereas tchi-faks in the other population were associated with nonspecific flight responses. In both populations of Coquerel’s sifakas, tchi-fak playbacks elicited anti-terrestrial predator responses. More strikingly, Verreaux’s sifakas exhibited anti-terrestrial predator responses after playbacks of growls in the population with a higher threat of predation by terrestrial predators, whereas Coquerel’s sifakas in the raptor-dominated habitat seemed to associate growls with a threat by raptors; the 2 other populations of each species associated a mild disturbance with growls. We interpret this differential comprehension and usage of alarm calls as the result of social learning processes that caused changes in signal content in response to changes in the set of predators to which these populations have been exposed since they last shared a common ancestor

Leftward Lateralization of Auditory Cortex Underlies Holistic Sound Perception in Williams Syndrome

BACKGROUND: Individuals with the rare genetic disorder Williams-Beuren syndrome (WS) are known for their characteristic auditory phenotype including strong affinity to music and sounds. In this work we attempted to pinpoint a neural substrate for the characteristic musicality in WS individuals by studying the structure-function relationship of their auditory cortex. Since WS subjects had only minor musical training due to psychomotor constraints we hypothesized that any changes compared to the control group would reflect the contribution of genetic factors to auditory processing and musicality. METHODOLOGY/PRINCIPAL FINDINGS: Using psychoacoustics, magnetoencephalography and magnetic resonance imaging, we show that WS individuals exhibit extreme and almost exclusive holistic sound perception, which stands in marked contrast to the even distribution of this trait in the general population. Functionally, this was reflected by increased amplitudes of left auditory evoked fields. On the structural level, volume of the left auditory cortex was 2.2-fold increased in WS subjects as compared to control subjects. Equivalent volumes of the auditory cortex have been previously reported for professional musicians. CONCLUSIONS/SIGNIFICANCE: There has been an ongoing debate in the neuroscience community as to whether increased gray matter of the auditory cortex in musicians is attributable to the amount of training or innate disposition. In this study musical education of WS subjects was negligible and control subjects were carefully matched for this parameter. Therefore our results not only unravel the neural substrate for this particular auditory phenotype, but in addition propose WS as a unique genetic model for training-independent auditory system properties

Biology of learning in nonmammalian vertebrates: group report

Kroodsma DE, Bateson PPG, Bischof H-J, et al. Biology of learning in nonmammalian vertebrates: group report. In: Marler P, ed. The biology of learning: report of the Dahlem Workshop on the Biology of Learning, Berlin 1983, Oct.23 - 28. Life sciences research reports ; 29. Berlin: Springer; 1984: 399-418

Die lokale Oberflächenstruktur und -zusammensetzung bestimmt die Wasserstoffentwicklung an Eisen-Nickelsulfiden

Um leistungsfähigere Elektrokatalysatoren zu entwickeln, ist es notwendig, den Einfluss der Oberflächenstruktur und -zusammensetzung von Materialien mit hoher lokaler Auflösung besser zu verstehen. Dies trifft insbesondere auf die Entwicklung geeigneter Alternativen für Platin bei der elektrokatalytischen Wasserstofferzeugung zu. Elektrochemische Rasterzellmikroskopie (scanning electrochemical cell microscopy, SECCM) wurde benutzt, um die lokale elektrochemische Aktivität der Wasserstoffbildung an einkristallinen (111)-Oberflächen von Fe4.5Ni4.5S8, einem hochaktiven Elektrokatalysator für die Wasserstofferzeugung, zu untersuchen. In Kombination mit strukturaufklärenden Methoden zeigen wir, dass kleinste Veränderungen der chemischen Zusammensetzung die Aktivitat signifikant verändern können. Somit stellen die auf der Nanoskala durchgeführten elektrochemischen Messungen, ergänzt mit lokalen strukturellen Messungen sowie Kenntnis der lokalen Zusammensetzung ein wichtiges Hilfsmittel für das rationale Design neuer Katalysatoren dar