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

Abstract

In spite of extensive research conducted in studying pitch memory processing, knowledge about the functional anatomy of the brain while performing pitch discrimination task is still lacking. The purpose of this study was to investigate the effects of background noise and tonal frequencies on brain activation during a pitch discrimination task. Thirteen participants were presented with categories of low- and high-frequency tones during an fMRI scan. They listen, recognize and discriminate the target tone with the last tone in a series of four distracting tones. Cortical responses during which the participants engaged with the pitch discrimination task were explored globally and differentially with tonal frequency and background condition as factors. Similar integrative network consisting of bilateral superior temporal gyrus, pre-central gyrus, cerebellum, insula, putamen, inferior parietal lobe and supplementary motor area is established during the four pitch discrimination task conditions. The bilateral A1 and right M1 are effectively activated by noise and action respectively. Background noise increases the participants’ performance hence equalizing that in quiet, while participants performed significantly better in discriminating low-frequency tones as compared to high-frequency tones. This study revealed an integrative network that consists of areas responsible for pitch discrimination strategy. The bilateral primary auditory cortex played important roles in increasing participants’ pitch discrimination performance in noisy surrounding and in discriminating low frequency category of tones.