Where is sound interpreted in humans

When the cochlea receives the sound, it amplifies the signal detected by these hair cells and transmits the signal through the auditory nerve to the brain. While the ears are responsible for receiving sound from the environment, it is the brain that perceives and makes sense of these sounds. The auditory cortex of the brain is located within a region called the temporal lobe and is specialized for processing and interpreting sounds see Figure 3. The auditory cortex allows humans to process and understand speech, as well as other sounds in the environment.

What would happen if signals from the auditory nerve never reached the auditory cortex? Since many other areas of the brain are also active during the perception of sound, individuals with damage to the auditory cortex can often still react to sound.

In these cases, even though the brain processes the sound, it is unable to make meaning from these signals. One important function of human ears, as well as the ears of other animals, is their ability to funnel sounds from the environment into the ear canal. Though the outer ear funnels sound into the ear, this is most efficient only when sound comes from the side of the head rather than directly in front or behind it.

When hearing a sound from an unknown source, humans typically turn their heads to point their ear toward where the sound might be located. People often do this without even realizing it, like when you are in a car and hear an ambulance, then move your head around to try to locate where the siren is coming from.

Some animals, like dogs, are more efficient at locating sound than humans are. Sometimes animals such as some dogs and many cats can even physically move their ears in the direction of the sound!

Humans use two important cues to help determine where a sound is coming from. These cues are: 1 which ear the sound hits first known as interaural time differences , and 2 how loud the sound is when it reaches each ear known as interaural intensity differences.

If a dog were to bark on the right side of your body, you would have no problem turning and looking in that direction. This is because the sound waves produced by the barking hit your right ear before hitting your left ear, resulting in the sound being louder in your right ear.

Why is it that the sound is louder in your right ear when the sound comes from the right? Because, like objects in your house that block or absorb the sound of someone calling you, your own head is a solid object that blocks sound waves traveling toward you.

When sound comes from the right side, your head will block some of the sound waves before they hit your left ear.

This results in the sound being perceived as louder from the right, thereby signaling that that is where the sound came from. You can explore this through a fun activity. When a significant number of these cells are lost or damaged, hearing or balance disorders occur. Hair cell loss occurs for multiple reasons, including aging and damage to the ear from loud sounds. Damage or impairment to the process of adaptation may lead to the further loss of hair cells and, therefore, hearing.

Unlike many other species, including birds, humans and other mammals are unable to spontaneously regenerate these hearing cells. As the U. Stanford postdoctoral scholar Thomas Effertz , PhD, is also an author of the study. Prolonged exposure to loud sounds will eventually create sensorineural hearing loss as the cilia are damaged by the noise.

People who constantly operate noisy machinery without using appropriate ear protection are at high risk of hearing loss, as are people who listen to loud music on their headphones or who engage in noisy hobbies, such as hunting or motorcycling.

Sounds that are 85 decibels or more can cause damage to your hearing, particularly if you are exposed to them repeatedly. Sounds of more than decibels are dangerous even if you are exposed to them infrequently.

People who experience tinnitus a ringing or a buzzing sensation after being exposed to loud sounds have very likely experienced some damage to their cilia. Taking precautions when being exposed to loud sounds is important, as cilia do not grow back. While conductive hearing loss can often be improved through hearing aids that amplify the sound, they are of little help to sensorineural hearing loss.

But if the auditory nerve is still intact, a cochlear implant may be used. A cochlear implant is a device made up of a series of electrodes that are placed inside the cochlea.

The device serves to bypass the hair cells by stimulating the auditory nerve cells directly. The latest implants utilize place theory, enabling different spots on the implant to respond to different levels of pitch. The cochlear implant can help children who would normally be deaf hear. Chisolm, T. The aging auditory system: Anatomic and physiologic changes and implications for rehabilitation. International Journal of Audiology, 42 Suppl. Corey, D.

TRPA1 is a candidate for the mechano-sensitive transduction channel of vertebrate hair cells. Nature, , — Dettman, S.

Communication development in children who receive the cochlear implant younger than 12 months: Risk versus benefits. Ear and Hearing, 28 2, Suppl. Dorman, M. Ear drum vibrations continue into the middle ear where the 3 smallest bones in the human body are found. These are also known as the auditory ossicles — the hammer malleus , anvil incus and stirrups stapes — named because of their shapes.

The main function of these bones is sound amplification. Sound waves make them vibrate, causing sound to be transmitted to the inner ear. The inner ear is responsible for interpreting and transmitting sound auditory sensations and balance vestibular sensations to the brain. This is found in the temporal bone of the head and is made up of 3 related parts — the cochlea or spiral tube , 3 semicircular canals and the vestibule labyrinth.

The cochlea is responsible for hearing. It contains tiny hair-like cells connected to the acoustic nerve. This nerve changes energy vibrations in the inner ear fluid into nerve impulses that go to the brain. The brain interprets the impulses received to identify what you are hearing.