Functional magnetic resonance imaging of a human auditory cortex area involved in foreground-background decomposition.
Auditory foreground-background decomposition is a pattern recognition process which combines simultaneous and sequential grouping in complex sound sequences. Using functional magnetic resonance imaging with reduced scanner noise and stimulation through a new type of earphones, we investigated the possibility that this process activates topographically distinct areas of human auditory cortex. A basic matching-to-sample task with variable tones (sequential grouping) caused significant activity in three separate landmark-related territories on the supratemporal plane. A similar task in the presence of a strongly masking acoustic background pattern to challenge simultaneous grouping led to the distinction of the subterritory in which foreground signal-related or task-related signal properties were exclusively seen. In contrast to the remainder of territories the level of activity and the periodicity of the signal time-course was resistant to the masking influence of the background. This suggests that auditory foreground-background decomposition involves a specialized non-primary auditory cortex field. Generally, the findings demonstrate functional parcellation of auditory cortex for which the evidence in humans, in contrast to other primates, is only indirect to date.
Scheich
H
H
Federal Institute for Neurobiology, Magdeburg, Germany.
Baumgart
F
F
Gaschler-Markefski
B
B
Tegeler
C
C
Tempelmann
C
C
Heinze
H J
HJ
Schindler
F
F
Stiller
D
D
D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male