Hippocampal-cerebellar involvement in enhancement of performance in word-based BRT with the presence of background noise: An initial fMRI study.

Abstract

Background noise may impose deleterious effects on cognitive processing. However, noise below the threshold level may increase the ability to detect stimuli via stochastic resonance mechanisms (SR). The present study investigates whether task performance is deteriorated or enhanced by 5-dB SNR and, if the task performance is enhanced, whether this facilitation in performance points to a particular neural area that serves to attenuate noise and/or increase effective task performance. The areas of interest are the cerebellum and hippocampus due to their roles in working memory (WM) and their links with attention. Fifteen healthy young Malay adults performed three tasks during fMRI scanning: listening to babble noise (N), WM task in quiet (WMQ), and WM task in noise (WMN). Activated regions during N are bilateral STG and MTG. Both WM tasks produced similar activation in a network of areas in the frontal, temporal and parietal lobes. However, the two tasks demonstrated marked differences in the left hippocampus, right posterior cerebellum, and bilateral anterior cerebellum. Moreover, the results obtained from the behavioral task demonstrated that participants responded better in the presence of noise. These results support the hypothesis that the left hippocampus, right posterior cerebellum, and bilateral anterior cerebellum may be involved in attenuating noise and/or increasing attention to task performance, which could be due to SR mechanisms operating in the presence of noise. These results collectively suggest leftward asymmetries during the tasks with the right posterior cerebellum, bilateral anterior cerebellum, and left hippocampus providing compensatory attention processes, at least in the context of this study.

Assessing Human Cortical Activation and Network During Pitch Discrimination Task in Quiet and in Noisy Background

“…The bilateral auditory areas including the right insula lobe seemed to be more sensitive to low frequency tone discrimination but only if the task is performed in noisy condition. Likewise, putamen and hippocampus, the two brain areas that have been known to be involved in motor performance and working memory respectively (Abdul Manan et al, 2012), showed significantly higher activation in quiet as compared to in noise because they are more sensitive to high frequency tones discrimination but only when the task is performed in quiet. In conjunction with the behavioral test results explained earlier, one possible explanation for the significant increase in the brain activation in the bilateral auditory areas for the respective (Noise > Quiet) condition mentioned above is to compensate for the degradation of cognitive processing performance that has been affected by the white noise which distract attention from the main tasks.…”

“…In conjunction with the behavioral test results explained earlier, one possible explanation for the significant increase in the brain activation in the bilateral auditory areas for the respective (Noise > Quiet) condition mentioned above is to compensate for the degradation of cognitive processing performance that has been affected by the white noise which distract attention from the main tasks. In our previous study on the effects of noise on verbal working memory processing, the bilateral primary auditory cortices have shown significant increase in activation in noisy condition as compared to in quiet (Abdul Manan et al, 2012). In the case of (Quiet > Noise) condition, comparison with behavioral test results is not possible due its one-way nature of test.…”

“…The results obtained from this study also complement recent findings that show pitch discrimination deficits in patients with global cerebellar degeneration who were in a great difficulty accomplishing pitch discrimination task (Parsons et al, 2009). In our recent work on verbal working memory via backward repeat test (BRT), this brain structure has been found to be involved in attenuating noise and/or increasing attention to task performance (Abdul Manan et al, 2012). Nevertheless, the role of cerebellum in pitch discrimination has yet to be fully understood, given a vast number of studies conducted.…”

“…From the results obtained, it can be said that task performance seemed to be less influenced by the background. Based on the behavioral test results, one possible explanation rests on the ability of the brain to eliviate its performance in accomplishing the tone discrimination task especially when it is distracted by noise, thus equalizing the performance it has in quiet, an argument similar to the idea of stochastic resonance (Abdul Manan et al, 2012;Moss et al, 2004). However, to determine the main areas in the brain that are responsible for the compensation, a lower height threshold was implemented.…”

Kesan Penuaan ke atas Kehubungan Berkesan Otak semasa Pemprosesan Ingatan Bekerja daripada Perspektif Pemodelan Sebab dan Akibat Dinamik

“…Kawasan otak ini dipilih berdasarkan kepada keputusan pengkhususan kefungsian (Abdul Manan et al 2013;Manan et al 2015Manan et al , 2013Manan et al , 2012 (Yusoff et al 2011), pemprosesan penumpuan iaitu talamus (Alexander et al 2012) dan kawasan otak yang terlibat dalam pemprosesan ingatan bekerja iaitu girus presentral (PCG) (Mitchell et al 2000). Kawasan otak ini dipilih kerana peranan yang dimainkan semasa pemprosesan BRT.…”