Altered resting-state functional connectivity of the anterior cingulate cortex in rats post noise exposure

We aimed to find where and how noise-induced cochlear hearing loss affects the central nervous system during the early state and identify the neural substrate for aberrant patterns that mediating noise-related anxiety-/depression- like behaviors.

Broad band noise with 122 dB for 2 hours was conducted to induce hearing loss. We defined 0 day (N0D) and 10 days (N10D) post noise as the acute and sub-acute period. Behavioral tests (Open field test and light/dark test) and resting-state fMRI were computed to evaluate emotional conditions and aberrant neural activity. Functional connectivity analysis using the anterior cingulate cortex as a seed was computed to reveal the spatial distribution beyond auditory network during both periods.

Anxiety-/depression-like behaviors were found in rats with noise exposure. Between-group analysis revealed that N0D rats displayed widespread reductions in functional connectivity, spanning primary somatosensory cortex, medial geniculate body, inferior colliculus, cingulate cortex, cerebellar lobule comparing with N10D rats and a similar pattern was also occurred in comparison with the control group.

Taken together, an "acoustic-causing" network accounting for distress and gating of noise exposure related anxiety/depression was proposed.