Uncertainty-based informational masking in a vowel discrimination task for young and old Mongolian gerbils.

Informational masking emerges with processing of complex sounds in the central auditory system and can be affected by uncertainty emerging from trial-to-trial variation of stimulus features. Uncertainty can be non-informative but confusing and thus mask otherwise salient stimulus changes resulting in increased discrimination thresholds. With increasing age, the ability for processing of such complex sound scenes degrades.

Interaction of spatial source separation, fundamental frequency, and vowel pairing in a sequential informational masking paradigm in Mongolian gerbils.

Informational masking (IM) defines the compromised ability to perceive and analyze signals from a single source in a clutter of other sounds even if there is no interference between these signals' excitation patterns in the inner ear. IM is affected by the similarity between target and masker and the variation of stimulus features from trial to trial, that is, stimulus uncertainty, both modulating discrimination thresholds. We applied a sequential IM paradigm measuring Mongolian gerbils' sensitivity to detect level increments between constant-level standard (reference) and deviant (target) vowels with a level increase in a background of level-varying distracting (masker) vowels.

Uncertainty in location, level and fundamental frequency results in informational masking in a vowel discrimination task for young and elderly subjects.

Informational masking (IM) is defined as the compromised ability to perceive and analyze signals from a single sound source in a cacophony of sounds from other sources even if the excitation patterns produced by these signals in the auditory periphery are well separated from those produced by the sounds from the other sources. IM that causes an elevation of discrimination thresholds is affected by the similarity between target and masker and by stimulus uncertainty. Here, six young and six elderly subjects were asked to discriminate between sequentially presented reference and target vowels of the vowel pairs /I/-/i/, /æ/-/ε/, and /α/-/Λ/.

Processing of interaural phase differences in components of harmonic and mistuned complexes in the inferior colliculus of the Mongolian gerbil.

Harmonicity and spatial location provide eminent cues for the perceptual grouping of sounds. In general, harmonicity is a strong grouping cue. In contrast, spatial cues such as interaural phase or time difference provide for strong grouping of stimulus sequences but weak grouping for simultaneously presented sounds.