Brain Facts:
Sensory
| Topic | Discussion | Resource |
Auditory Impulse / Verbal Understanding |
The brain turns raw auditory impulses into meaningful verbal understanding. The process begins as impulses from primary hearing centers reach the brain’s main language center, usually located in the left cerebral hemisphere. For instant, the brain hears the sound “right” which sounds exactly the same as “write” and “rite”, and this auditory input is converted into intelligible words and sentences and understood logically in the context of grammar and syntax. Meanwhile a secondary language center, located in the right hemisphere, is informed of the left-side activity by impulses traveling across the connecting structures as well as directly from the primary hearing centers. Immediately, the right side, calling upon its powers of abstract, intuitive perception, begins to interpret the emotional tones and verbal inflections that give spoken language it subtle shades of meaning. |
Andrew Newberg, MD, Eugene D’Aquili, MD, PhD, and Vince Rause |
| Five Senses | Five senses: taste, smell, sight, hearing, and kinesthesia (feeling sense). We make most of the decisions that affect our behavior primarily using only three of these senses: visual, auditory, and kinesthetic systems. | Anthony Robbins Unlimited Power |
Hearing |
The brain has two major goals for sound information: to locate a sound in space, so you can look towards the sound’s source, and to identify the sound. Neither task is easy. Each is accomplished in different parts of the brain. |
Sandra Aamodt, PhD and Sam Wang, PhD |
Hearing |
Sound information from the two ears is brought together in the neurons of the brainstem. |
Sandra Aamodt, PhD and Sam Wang, PhD |
Hearing |
The outer ear transmits sound waves to an organ in the inner ear call the cochlea. The cochlea contains the ear’s sound-sensing cells, which are arranged in row along a long, coiled membrane. Sound pressure moves the fluid in the ear, causing the membrane to vibrate in different ways depending on the sound’s frequencies. This vibration activates the sensors, called hair cells because they have a bundle of fine fibers that stick up from the top of the cell like a punk hairdo. Movement of these fibers transforms the vibration signal into an electrical signal that can be understood by other neurons. |
Sandra Aamodt, PhD and Sam Wang, PhD |
Hearing |
One-third of people over sixty and half those over seventy have hearing loss. The most common cause is long-term exposure to loud noises. Baby boomers are losing their hearing earlier than their parents and grandparents did, presumably because our worlds are noisier than they used to be. |
Sandra Aamodt, PhD and Sam Wang, PhD |
Hearing |
Noise causes hearing loss by damaging hair cells, which detect sounds in the inner ear. Hair cells have a set of thin fibers call the hair bundle extending from their surface that moves in response to sound vibrations. If the hair bundle moves too much, the fibers can tear, and that hair cell will no longer be able to detect sound. The hair cells that respond to high-pitched sounds (like a whistle) are most vulnerable and tend to be lost earlier than the hair cells that respond to low-pitched sounds (like a foghorn). That’s why noise-related hearing loss tends to begin with difficulty in hearing high-pitched sounds. |
Sandra Aamodt, PhD and Sam Wang, PhD |
| Sensory Development | You are born with eyes and ears open, ready to engage and absorb the world. As these sensory areas develop, they begin shaping more remote parts of the brain, the floors above the sensory foundation. A flexible brain develops through a long and complex interaction with the world and builds the circuits of the mind. | Steven R. Quartz, PhD, and Terrence J. Sejnowski, PhD. |
| Smell | While the human sense of smell is relatively weak compared to that of mammals, we nevertheless have 347 different types of sensory neurons in the olfactory layer for smell inside the nose. Each one detects a different type of order, and all the varied aromas and stenches we know result from mixture of responses of these 347 types of receptor cells. | Judith Horstman |
| Smell | Smell is so emotionally evocative because the olfactory nerve is the only sensory channel that links directly to the brain’s emotional centers in the limbic system. All of the other senses reach the limbic system through intermediary connections. | Richard Restak Mozart’s Brain and the Fighter Pilot p. 84 |
Visual Association |
The visual association area may play a prominent role in religious and spiritual experiences that involve visual imagery. For example, the visual association area is likely to be active in individuals who use images (such as of a candle or cross) to help facilitate meditation or prayer. Furthermore, spontaneous visions that occur during meditation and prayer or that are associated with unusual spiritual states such as near-death experiences may also originate in this area. We know this in part, because electrical stimulation of this area results in various types of visual experiences. In addition, the area is closely tied to the brain’s memory banks, so it is possible that stored visions are remembered or associated—perhaps not fully consciously—with later religious and spiritual experiences. |
Andrew Newberg, MD, Eugene D’Aquili, MD, PhD, and Vince Rause |
| Wernicke’s Area | When we hear and understand words, something called the auditory association area (just behind the auditory area proper) is active. But in order to read, as well as to understand speech, we need a combination of visual and auditory processing. This occurs in the so-called receptive language area (Wernicke’s area), which receives signals from both the auditory and visual association areas. | Richard Restak, MD |
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