How does the basilar membrane respond to different frequencies along its length?

How does the basilar membrane respond to different frequencies along its length?

• A. Low frequencies peak near the base and high frequencies near the apex.
• B. High frequencies peak near the base and low frequencies near the apex.
• C. All frequencies peak at the same place.
• D. There is no frequency-based pattern.

Answer: (B)

The basilar membrane encodes frequency by a place-based response along its length. Its stiffness and width change from base to apex, being narrow and stiff at the base and wide and flexible at the apex. When a sound travels through the cochlea, it generates a traveling wave that reaches its greatest displacement at a specific location depending on the frequency: high-frequency sounds cause the peak near the base, while low-frequency sounds peak farther toward the apex. This tonotopic organization means each frequency activates a distinct region, with high frequencies mapped to the base and low frequencies to the apex, enabling precise frequency separation.

The basilar membrane encodes frequency by a place-based response along its length. Its stiffness and width change from base to apex, being narrow and stiff at the base and wide and flexible at the apex. When a sound travels through the cochlea, it generates a traveling wave that reaches its greatest displacement at a specific location depending on the frequency: high-frequency sounds cause the peak near the base, while low-frequency sounds peak farther toward the apex. This tonotopic organization means each frequency activates a distinct region, with high frequencies mapped to the base and low frequencies to the apex, enabling precise frequency separation.