title: Regularity encoding and deviance detection of frequency modulated sweeps: human middle- and long-latency auditory evoked potentials.
abstract: Fast encoding of frequency modulated (FM) sweeps is crucial for communication. In humans, FM sweeps deviating from the acoustic regularity elicit the mismatch negativity (MMN) evoked potential. Yet, direction sensitivity to FM sweeps is found in animals' primary auditory cortex, upstream of MMN sources found in humans. Here, we were interested in whether direction deviants of complex FM sweeps modulated brain responses earlier than MMN. We used a controlled oddball paradigm, and measured the middle latency responses (MLRs) and the MMN. Our results showed a repetition enhancement to the standards at the Pa component of the MLR and a genuine MMN in the later response range. These results show that, early in the cortical hierarchy, the system is sensitive to the physical characteristics of the repetitive stimuli, but a higher-order mechanism is needed to detect violations of the acoustic regularity.
authors.affiliation: Institute for Brain, Cognition and Behavior (IR3C) and Cognitive Neuroscience Research Group, Department of Psychiatry and Clinical Psychobiology, University of Barcelona, Catalonia, Spain.
authors.forename: Miriam
authors.initials: M
authors.lastname: Cornella
authors.forename: Sumie
authors.initials: S
authors.lastname: Leung
authors.forename: Sabine
authors.initials: S
authors.lastname: Grimm
authors.forename: Carles
authors.initials: C
authors.lastname: Escera
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D004569:Electroencephalography / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D055815:Young Adult
keywords: Frequency modulated (FM); Middle latency responses (MLRs); Mismatch negativity (MMN); Sweeps