Open AccessEffects of attention on dichotic listening: An 15 O‐PET study
Author(s) -
Hugdahl Kenneth,
Law Ian,
Kyllingsbæk Søren,
Brønnick Kolbjørn,
Gade Anders,
Paulson Olaf B.
Publication year - 2000
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/(sici)1097-0193(200006)10:2<87::aid-hbm50>3.0.co;2-v
Subject(s) - dichotic listening , psychology , audiology , laterality , stimulus (psychology) , auditory cortex , sensory system , functional magnetic resonance imaging , stimulus modality , statistical parametric mapping , neuroscience , cognitive psychology , magnetic resonance imaging , medicine , radiology
The present study investigated the effect of attention on brain activation in a dichotic listening situation. Dichotic listening is a technique to study laterality effects in the auditory sensory modality. Two different stimuli were presented simultaneously, one in each ear. Twelve subjects listened to lists of consonant‐vowel syllables, or short musical instrument passages, with the task of detecting a “target” syllable or musical instrument by pressing a button. The target stimulus appeared an equal number of times in the left and right ear. The subjects were instructed to either concentrate on the stimuli presented in both ears, or only on the left or right ear stimulus. Brain activation was measured with 15 O‐PET, and significant changes in regional normalized counts (rNC) were evaluated using statistical parametric mapping (SPM96) software. Concentrating on either the right or left ear stimulus significantly decreased activity bilaterally in the temporal lobes compared to concentrating on both ear stimuli, at the expense of an increased activation in the right posterior and inferior superior parietal lobe. The CV‐syllables activated areas corresponding to the classic language areas of Broca and Wernicke. The musical instrument stimuli mainly activated areas in visual association cortex, cerebellum, and the hippocampus. An interpretation of the findings is that attention has a facilitating effect for auditory processing, causing reduced activation in the primary auditory cortex when attention is explicitly recruited. The observed activations in the parietal lobe during the focused attention conditions could be part of a modality non‐specific “attentional network”. Hum. Brain Mapping 10:87–97, 2000. © 2000 Wiley‐Liss, Inc.