Estimation of false discovery rates for wavelet-denoised statistical parametric maps.

Correction for multiple comparisons in neuroimaging data is an important area of research. Recently, wavelet-based methods have gained popularity and have been reported to achieve better sensitivity compared to spatial domain methods. However, these techniques produce smoothed statistical maps which are difficult to interpret. The generated maps have to be thresholded again in the spatial domain to delineate active from inactive regions. The selection of a proper threshold satisfying the required error rate control is not straightforward. In this paper, a framework is proposed for thresholding wavelet-denoised maps in which a rejection region is fixed, and the achieved false discovery rate (FDR) is estimated. This approach provides a meaningful strategy to choose thresholds for wavelet-denoised statistical parametric maps (SPMs). Two FDR estimation algorithms were used to assess the achieved error rate control when thresholding wavelet filtered SPMs at various rejection regions. Their performance was evaluated using both simulated and resting fMRI data. The proposed framework was also applied on in vivo data.

Impaired detection of variable duration embedded tones in ectopic NZB/BINJ mice.

Utilizing rodent models, prior research has demonstrated a significant association between focal neocortical malformations (i.e. induced microgyria, molecular layer ectopias), which are histologically similar to those observed in human dyslexic brains, and rate-specific auditory processing deficits as seen in language impaired populations. In the current study, we found that ectopic NZB/BINJ mice exhibit significant impairments in detecting a variable duration 5.6 kHz tone embedded in a 10.5 kHz continuous background, using both acoustic reflex modification and auditory event-related potentials (AERP). The current results add further support to the association between focal cortical malformations and impaired auditory processing, and the notion that these auditory effects may occur regardless of the cortical location of the anomaly.