Figure 2. Time line showing day and approximate time of day for each procedure.

Acoustic startle reflex testing (ASR) for tinnitus perception, auditory brainstem response testing (ABR) for hearing loss, tinnitus induction, manganese injection and imaging in control (A), salicylate (B) and noise (C) groups during a given day. 8 – first eight hrs of day, 16 – second eight hr period of day, 24 – last eight hr period of day, SA – salicylate injection, NE – noise exposure, Mn²⁺ - manganese injection, MRI – magnetic resonance imaging.