Neural sources involved in auditory target detection and novelty processing: An event-related fMRI study

Abstract

We used event-related functional magnetic resonance imaging (erfMRI) techniques to examine the cerebral sites involved with target detection and novelty processing of auditory stimuli. Consistent with the results from a recent erfMRI study in the visual modality, target processing was associated with activation bilaterally in the anterior superior temporal gyrus, inferior and middle frontal gyrus, inferior and superior parietal lobules, anterior and posterior cingulate, thalamus, caudate, and the amygdala/hippocampal complex. Analyses of the novel stimuli revealed activation bilaterally in the inferior frontal gyrus, insula, inferior parietal lobule, and in the inferior, middle, and superior temporal gyri. These data suggest that the scalp recorded event-related potentials (e.g., N2 and P3) elicited during similar tasks reflect an ensemble of neural generators located in spatially remote cortical areas.

The hemodynamics of oddball processing during single-tone and two-tone target detection tasks

“…This extensive network of brain regions associated with target detection may be similar to the attention network discussed by Mesalum (Mesulam, 1990;Mesulam, 2000). Others have suggested that processing salient stimuli is associated with an 'reflexive' or 'automatic' orienting process that is reliably activates an extensive neural network despite the low probability that all activated brain regions are required for successful task performance (Kiehl et al, 2001a;Kiehl et al, 2001b;Kiehl & Liddle, 2003;Kiehl et al, 2005).Also consistent with study hypotheses, target detection was associated with greater hemodynamic activity during the single-tone condition compared to the two-tone condition in bilateral middle temporal gyrus, inferior frontal and middle prefrontal gyri. These findings are consistent with electrophysiological and magnetoencephalogram studies of single-, two-and three-tone oddball tasks.…”

“…This study illustrates that a large ensemble of brain regions, known to be involved in target detection during three-tone auditory oddball tasks (Kiehl et al, 2001a;Kiehl et al, 2001b;Kiehl & Liddle, 2003), also are engaged by target detection in single-and two-tone auditory oddball paradigms. Target detection in both single-tone and two-tone fMRI auditory oddball tasks elicited significant hemodynamic activity in all 34 a priori-defined regions of interest (ROIs).…”

“…Hemodynamic activity was examined in a group of participants who performed both a two-stimulus version of the oddball and a version containing only targets (single-stimulus) (Polich et al, 1994;Polich & Heine, 1996;Polich & Margala, 1997). The first aim of this study was to determine whether the brain areas previously activated by target detection during a three-stimulus oddball task (Kiehl et al, 2001a;Kiehl et al, 2001b;Kiehl & Liddle, 2003) also were activated by the different contextual task manipulations. It was hypothesized that target stimuli would elicit hemodynamic activity in the same diverse, spatially distributed neural network implicated in previous depth electrode and three-stimulus fMRI oddball studies.…”

“…Statistical significance of activity within the ROIs was maintained below an alpha of .05 using small volume correction (Worsley et al, 1996) and the false discovery rate (Nichols & Hayasaka, 2003). 2 Relatively small clusters were used to prevent overlap for those ROIs that were close together; one ROI from previous work (Kiehl et al, 2001b); located in the right temporal pole was excluded because of such overlap.To address the question of whether there are differences in the amplitude of the hemodynamic response elicited in the single-and two-tone conditions, a supplementary analysis examining the entire brain was done. For these post hoc tests, a correction for multiple comparisons used the False Discovery Rate to control Type I error (Nichols & Hayasaka, 2003).…”

Schizophrenia Subjects Show Intact Success-Related Neural Activation but Impaired Uncertainty Processing during Decision-Making

“…Specifically, attentional processes that involve sustained, and possibly selective, attention (Coull et al, 1996), switching from task-relevant local to global targets (Fink et al, 1996;Lamb et al, 1989), voluntary attentional control (Hopfinger et al, 2000), and the distinction between taskirrelevant and task-relevant events (Downar et al, 2001;Kiehl et al, 2001;McCarthy et al, 1997) support the view that this area is critical for the extraction and selection of task-relevant information. Moreover, this area has been implicated in inhibitory control in a number of different paradigms (Garavan et al, 1999;Menon et al, 2001;Rubia et al, 2001b;Steel et al, 2001;Doricchi et al, 1997), that is, the allocation of resources to a response that has to compete with a highly overlearned and potentially habitual behavior.…”