  The extraordinary sensitivity of the mammalian inner ear has captivated
scientists for decades, largely due to the crucial role played by the outer
hair cells (OHCs) and their unique electromotile properties. Typically arranged
in three rows along the sensory epithelium, the OHCs work in concert via
mechanisms collectively referred to as the "cochlear amplifier" to boost the
cochlear response to faint sounds. While simplistic views attribute this
enhancement solely to the OHC-based increase in cochlear gain, the inevitable
presence of internal noise requires a more rigorous analysis. Achieving a
genuine boost in sensitivity through amplification requires that signals be
amplified more than internal noise, and this requirement presents the cochlea
with an intriguing challenge. Here, we analyze the effects of spatially
distributed cochlear-like amplification on both signals and internal noise.
