Assesing the influence of scanner background noise on auditory processing. I. AnfMRI study comparing three experimental designs with varying degrees of scanner noise

Department of Psychology, Stanford University, Stanford, California, USA.
Human Brain Mapping (Impact Factor: 5.97). 08/2007; 28(8):703-20. DOI: 10.1002/hbm.20298
Source: PubMed


We compared two experimental designs aimed at minimizing the influence of scanner background noise (SBN) on functional MRI (fMRI) of auditory processes with one conventional fMRI design. Ten subjects listened to a series of four one-syllable words and had to decide whether two of the words were identical. This was contrasted with a no-stimulus control condition. All three experimental designs had a duration of approximately 17 min: 1) a behavior interleaved gradients (BIG; Eden et al. [1999] J Magn Reson Imaging 41:13-20) design (repetition time, TR, = 6 s), where stimuli were presented during the SBN-free periods between clustered volume acquisitions (CVA); 2) a sparse temporal sampling technique (STsamp; e.g., Gaab et al., [2003] Neuroimage 19:1417-1426) acquiring only one set of slices following each of the stimulations with a 16-s TR and jittered delay times between stimulus offset and image acquisition; and 3) an event-related design with continuous scanning (ERcont) using the stimulation design of STsamp but with a 2-s TR. The results demonstrated increased signal within Heschl's gyrus for the STsamp and BIG-CVA design in comparison to ERcont as well as differences in the overall functional anatomy among the designs. The possibility to obtain a time course of activation as well as the full recovery of the stimulus- and SBN-induced hemodynamic response function signal and lack of signal suppression from SBN during the STsamp design makes this technique a powerful approach for conducting auditory experiments using fMRI. Practical strengths and limitations of the three auditory acquisition paradigms are discussed.

Download full-text


Available from: Nadine Gaab, Jan 07, 2014
  • Source
    • "mpre - hensive review of scanner - related noise issues . However , scanner - noise contamination is not completely eliminated by the unique procedures noted above and their influence on experimental audi - tory tasks can vary ; being dependent on the type of acquisition paradigm utilized with greatest impact on auditory cortical areas ( e . g . , Gaab et al . , 2007a , b ) . In other cases where functional locali - zation of brainstem structures during acoustic activation might be of interest , cardiac gating may also be necessary to eliminate movement - related " anatomic " noise ( blurring ) associated with other physiological variables such as respiration and cardiovascular induced interactions ("
    [Show abstract] [Hide abstract]
    ABSTRACT: Manganese enhanced magnetic resonance imaging (MEMRI) is a method used primarily in basic science experiments to advance the understanding of information processing in central nervous system pathways. With this mechanistic approach, manganese (Mn2+) acts as a calcium surrogate, whereby voltage-gated calcium channels allow for activity driven entry of Mn2+ into neurons. The detection and quantification of neuronal activity via Mn2+ accumulation is facilitated by “hemodynamic-independent contrast” using high resolution MRI scans. This review emphasizes initial efforts to-date in the development and application of MEMRI for evaluating tinnitus (the perception of sound in the absence of overt acoustic stimulation). Perspectives from leaders in the field highlight MEMRI related studies by comparing and contrasting this technique when tinnitus is induced by high-level noise exposure and salicylate administration. Together, these studies underscore the considerable potential of MEMRI for advancing the field of auditory neuroscience in general and tinnitus research in particular. Because of the technical and functional gaps that are filled by this method and the prospect that human studies are on the near horizon, MEMRI should be of considerable interest to the auditory research community.
    Hearing research 05/2014; 311. DOI:10.1016/j.heares.2014.02.003 · 2.97 Impact Factor
  • Source
    • "Moreover, scanner noise overlaps in acoustic frequency with certain stimuli [8,15,16], leading to masking effects [17] and an increase in attentional resources required for the disambiguation of signal sources [18-20], as well as nonlinear interactions in the auditory cortex [16,21]. Scanning protocols that feature a decrease in scanner noise, such as sparse temporal sampling [22-24] have been proven to decrease the deleterious effects of scanner noise as demonstrated with fMRI (for reviews see 11,14), magnetoencephalography [25], positron emission tomography [26], as well as electroencephalography experimental results which show that during auditory working memory tasks, listening to recordings of scanner noise can differentially alter significantly the amplitude or latency of the P1, N1, N2 and P3 event related potential components [27]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of the present study was the investigation of interaction effects between functional MRI scanner noise and affective neural processes. Stimuli comprised of psychoacoustically balanced musical pieces, expressing three different emotions (fear, neutral, joy). Participants (N=34, 19 female) were split into two groups, one subjected to continuous scanning and another subjected to sparse temporal scanning that features decreased scanner noise. Tests for interaction effects between scanning group (sparse/quieter vs continuous/noisier) and emotion (fear, neutral, joy) were performed. Results revealed interactions between the affective expression of stimuli and scanning group localized in bilateral auditory cortex, insula and visual cortex (calcarine sulcus). Post-hoc comparisons revealed that during sparse scanning, but not during continuous scanning, BOLD signals were significantly stronger for joy than for fear, as well as stronger for fear than for neutral in bilateral auditory cortex. During continuous scanning, but not during sparse scanning, BOLD signals were significantly stronger for joy than for neutral in the left auditory cortex and for joy than for fear in the calcarine sulcus. To the authors' knowledge, this is the first study to show a statistical interaction effect between scanner noise and affective processes and extends evidence suggesting scanner noise to be an important factor in functional MRI research that can affect and distort affective brain processes.
    PLoS ONE 11/2013; 8(11):e80564. DOI:10.1371/journal.pone.0080564 · 3.23 Impact Factor
  • Source
    • "Data for Experiment 2 were acquired using the same EPI sequence as Experiment 1 except TR = 8 s. For Experiment 2 a sparse sampling sequence was be used in order to reduce the effect of scanner noise on spontaneous brain activity (Gaab et al., 2007a,b, 2008). Functional data were processed using the AFNI software package (Cox, 1996). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Previous studies suggest that there may be a distinct relationship between spontaneous neural activity and subsequent or concurrent self-specific stimulus-induced activity. This study aims to test the impact of spontaneous activity as recorded in an eyes-open (EO) resting state as opposed to eyes-closed (EC) on self-specific versus non-self-specific auditory stimulus-induced activity in fMRI. In our first experiment we used self-specific stimuli comprised of the subject's own name and non-self-specific stimuli comprised of a friend's name and an unknown name, presented during EO versus EC baselines in a 3 name condition × 2 baseline design. In Experiment 2 we directly measured spontaneous activity in the absence of stimuli during EO versus EC to confirm a modulatory effect of the two baseline conditions in the regions found to show an interaction effect in Experiment 1. Spontaneous activity during EO was significantly higher than during EC in bilateral auditory cortex and non-self-specific names yielded stronger signal changes relative to EO baseline than to EC. In contrast, there was no difference in response to self-specific names relative to EO baseline than to EC despite the difference between spontaneous activity levels. These results support an impact of spontaneous activity on stimulus-induced activity, moreover an impact that depends on the high-level stimulus characteristic of self-specificity.
    Frontiers in Human Neuroscience 07/2013; 7:437. DOI:10.3389/fnhum.2013.00437 · 3.63 Impact Factor
Show more