Sunday, July 21, 2019

Monday, July 8, 2019

Your 8 Senses

Photo: Child and Therapist learning in the STAR Institute Treatment Center's world famous sensory garden.
 You Have Eight Sensory Systems
(Please note: figures below are from Wikipedia)


The five basic sensory systems:

          1. Visual

          2. Auditory

          3. Olfactory (smell) System

          4. Gustatory (taste) System

          5. Tactile System

The three sensory systems Ayres focused on in describing sensory integration dysfunction:

          5. Tactile System (see above)

          6. Vestibular (sense of head movement in space) System

          7. Proprioceptive (sensations from muscles and joints of body) System

The most recently discussed set of sensations related to internal organs

          8. Interoception

A.  The five basic sensory systems:

1.  Visual System
The visual system is responsible for seeing.

The primary visual area of the brain is the occipital lobe (see figure). Projections are received from the retina (through the thalamus) where different types of information are encoded. Types of visual information include: color, shape, orientation, and motion. From the ventral stream in the occipital lobe information projects to the temporal lobe to process what objects are. From the dorsal stream, information goes to the parietal lobes to process where objects are located.

2.  Auditory System
The auditory system is responsible for hearing.

The primary auditory cortex is located in the superior temporal gyrus of the brain (see figure). Specific sound frequencies can be mapped precisely onto the primary auditory cortex. Particular areas in the auditory cortex process changes in sound frequency or amplitude, while other areas process combinations of sound frequencies. The major area involved in comprehending language, (called Wernike’s area) is located in the left hemisphere in most people.

3.  Olfactory (smell) System

The olfactory system is responsible for processing smell.

The olfactory bulb is located in the most forward part of the brain on the bottom side of the brain (see figure). The olfactory bulb transmits smell information from the nose to the brain, and is thus necessary for a proper sense of smell. Unlike the other sensory systems, the olfactory bulb has only one source of sensory input (neurons of the olfactory epithelium) and one output. Thus it is assumed to be more of a filter than an associative circuit that has many inputs and many outputs.

The olfactory bulb does receive “top-down” information from areas such as the amygdala, neocortex, hippocampus, and others. It has four functions:

discriminating among odors
enhancing detection of odors
filtering out many background odors
allowing higher brain areas related to arousal and attention to modify the detection and/or the discrimination of odors
Looking up from the base of the brain

 4.  Gustatory (taste) System
The Gustatory system is responsible for the sense of taste.

It allows us to discriminate between safe and harmful foods. Usually, individuals prefer sweet and salty tastes to sour or bitter tastes. Detecting salt is critical to keeping a regulated and stable internal body environment. This taste is perceived positivity because it facilitates re-uptake of water into the blood. Since it helps survival, salt is perceived as a pleasant taste by most humans.

Sour taste can be good in small quantities, but when it gets too sour it becomes unpleasant to taste. This has occurred through evolution to protect us from eating over-ripe fruit, rotten meat, and other spoiled foods (dangerous because of bacteria which grow in these environments).

The bitter taste is almost completely unpleasant to humans. This is because many dangerous pharmacological agents taste bitter, including caffeine, nicotine, and strychnine. Some bitter tastes can be overcome (note how popular Starbucks is world wide! Also note how many medicines when chewed, have a bitter taste, apparently being interpreted by our bodies as poisons.)

Sweet taste signals that carbohydrates are present. Carbohydrates have a high calorie count and are desirable (humans in the distant past did not know when their next meal would occur, so they evolved to want/need to eat sweet tastes.)

The primary gustatory cortex is located near the somatotopic region for the tongue, in the insular cortex deep in the lateral fissure with the secondary taste areas in the opercula (see figure). This means the location is folded deeply within the cortex within the lateral sulcus between the temporal and frontal lobes.

5.  Tactile System
The tactile system is responsible for processing touch information from the body.

The body sends tactile information to the somatosensory cortex through neural pathways to the spinal cord, the brain stem, and the thalamus. The primary somatosensory cortex is the primary receptive area for touch sensations and is located in the lateral postcentral gyrus, a prominent structure in the parietal lobe of the human brain.

Due to its many connections to other brain areas, the somatosensory cortex is the part of the nervous system that integrates touch, pressure, temperature, and pain.

The tactile system is extremely important in SPD. Many individuals with the disorder have tactile symptoms such as tactile defensiveness or under-responsivity to touch and pain. The touch system is one of the three foundational systems used in sensory integration treatment.

B.  The three sensory systems Ayres focused on in describing the treatment of sensory integration dysfunction:

5.  Tactile system (see description above)

6.  Vestibular System

The vestibular system contributes to balance and orientation in space. It is the leading system informing us about movement and position of head relative to gravity.

Our movements include two positions rotations and linear directionality. Thus, the vestibular system has two related components: the semicircular canal system, (related to detecting rotation) and the otoliths, (related to detecting linear acceleration/deceleration).

The vestibular system sends signals primarily to the neural parts of the brain that control our eye movements, and that keep us upright.

The vestibular system contains three semicircular canals, which are approximately at right angles to each other:

the horizontal canal, which detects rotation around a vertical axis (as when you do spins in ice skating),

the anterior semicircular canal, detects movement in forward/backward plane as in a nodding movement,

the posterior canal, detects movement in a frontal plane as in when cartwheeling.

The canal on each side has an almost parallel counterpart on the other side. Each pair of canals works in a push-pull fashion: when one is stimulated, its partner is inhibited. Together the partners allow us to sense rotation in all directions.

Emphasis on the function of the vestibular system comes from Ayres influence when she identified sensory processing disorders as a new condition. This sensory system has a broad influence in many parts of the brain projecting to:

The cerebellum (to effect movements of the head, eyes, and posture).
Cranial nerves III, IV, and VI (to permit the eyes to fix on a moving object while staying in focus).
Reticular formation (to signal how to adjust circulation and breathing when the body assumes a new position).
Spinal Cord (to allow quick reflex reactions related to balancing).
Thalamus (to control head and body motor responses).
The information above is only a simple introduction to the role of the vestibular system as it relates to SPD. The figure below depicts the complex vestibular system. This figure is in the public domain from Gray’s Anatomy (book).

7.  Proprioception
Proprioception (sense of muscle and/or joint movements) System

The proprioceptive system (sometimes abbreviated as “prop” by therapists when they talk about it) senses the position, location, orientation, and movement of the body muscles and joints. Proprioception provides us with the sense of the relative position of neighboring parts of the body and effort used to move body parts.

Proprioception is activated by input to a proprioceptor in the periphery of the body. The proprioceptive sense combines sensory information from neurons in the inner ear (detecting motion and orientation) and stretch receptors in the muscles and the joint-supporting ligaments for stance.

Two types of proprioception exist:

  • Conscious proprioception, which travels up the posterior column-medial lemniscus pathway to the cerebrum; and
  • Unconscious proprioception which travels up the dorsal spinocerebellar tract,[20] to the cerebellum.

Proprioception was felt by Ayres to be the foundation (with vestibular impairments) of SPD. It is one of the three sensory systems used by SI trained therapists as the cornerstone of the sensory aspect of advanced treatment.

Temporary proprioceptive impairment is reported during times of quick growth, mostly during adolescence. Other large increases or drops in bodyweight/size due to fluctuations of fat (e.g., liposuction) and/or muscle content (e.g., body-building) also affect proprioception.

Proprioception is occasionally impaired in typically developing individuals, for example, if you are tired. Generally speaking we do not notice out proprioceptive sense because we disregard through habituation, desensitization, or adaptation sensory stimuli that is continuously present. In essence, the habituation makes the proprioceptive sensory impressions disappear. One practical advantage of this is that unnoticed sensation continue in the background while an individual’s attention can move to another concern.

Temporary impairment of proprioception has also been known to occur from an overdose of vitamin B6 and or by cytotoxic factors such as chemotherapy.
8. Interoception

Free interoception download

Watch this video explanation

The eighth, often neglected, but frequently problematic sensory system in SPD is the Interoceptive System. Interoception refers to sensations related to the physiological/physical condition of the body. Interoceptors are internal sensors that provide a sense of what our internal organs are feeling. Hunger and thirst are examples of interoception.

Interoception detects responses that guide regulation, including hunger, heart rate, respiration and elimination. The Interoceptive stimulation is detected through nerve endings lining the respiratory and digestive mucous membranes. Interoception works the vestibular and proprioceptive senses to determine how an individual perceives their own body. Well-modulated interoception helps the individual detect proprioceptive and vestibular sensation normally. For example, if a person feels his/her heart pounding, while it is not comfortable, trauma from the stimulation is not likely; nor will the stimulation be craved. The same is true for hunger and thirst, as well as the feeling of the need to urinate or have a bowel movement.

Interoception is associated with autonomic motor control, and is different than mechano-reception (in the skin) and proprioception (in the muscles and joints). Interoception is located in the dorsal posterior insula and it creates distinct feelings from the body including pain, temperature, itch, muscular and visceral sensations, vasomotor activity, hunger, thirst, and the need for air. In humans, the primary interoceptive activity occurs in the right anterior insula, which provides the basis for subjective feelings of ones’ emotional awareness.

Some researchers believe that our perceptions of well-being, energy and stress are based on sensations representing the physiological condition of our bodies. They suggest that interoception is a foundation subjective feelings, emotion and self-awareness. There is evidence that the anterior insula-cingulate system may integrate Interoceptive information with emotional salience to form a subjective representation of the body; while the mid-cingulate cortex, are more likely involved in environmental monitoring, response selection, and body orientation (see Taylor KS, Seminowicz DA, Davis KD (2009). Two systems of resting state connectivity between the insula and cingulate cortex. Human brain mapping, 30(9), 2731-2745).

See below for general diagram of the neuroanatomical locations noted in above descriptions. The brains depicted below are shown from a side view with the nose pointing to the left.

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How Do We Remember Things And Why? How Does Our Brain and Memory Work?

Why do we remember our first date, our first kiss, but not what we wrote to our partner at WhatsApp three weeks ago? Why can children name us 802 different Pokémon characters, but not the capital of Romania? Why can students get every spell from Harry Potter right, but forget their Latin vocabulary in the test?

How Do You Remember Things And Why?
Our brain works in a fascinating way. It is not only interesting, but very likely useful to understand how and why our memories are saved and recalled.
Life means learning and learning is easier when one understands how memory and its recalls works.

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Saturday, July 6, 2019

What is Multisensory Learning?

Multisensory learning means learning through more than one sensory system at the same time. I suggest presenting information to infants using more than one sensory system. You can do this whether you are teaching your baby new words, about music, math, colors, or other concepts.

With multisensory learning, what your baby sees should match what she hears. Other sensory information should match as well.

Why Is It Important to Use Multisensory Learning?
Babies often learn more with multisensory learning than they do through a single sensory system (Rose & Ruff, 1987). Children naturally use all of their senses when exploring their environments. For example, when learning about a toy, babies generally look at the toy, touch the toy, listen to sounds made by the toy, smell the toy, or put the toy in their mouths. Babies also often use movements to help them learn and this can help them gather additional information.

According to Edelman’s Theory of Neuronal Group Selection (a theory about brain development), more elaborate brain connections form when multisensory learning occurs compared to single sensory learning. Multisensory learning reaches visual learners, auditory learners, tactile learners, and physical or kinesthetic learners.

Be as Precise as You Can with Sensory Information
The sensory information is locked in time from the different sensory systems, so it is much better if you add extra sensory information that is relevant. For instance, if you are counting your baby’s toes while she or he watches, say each number at the precise instant that you touch your baby’s toes. This would give your baby three types of sensory information (visual, auditory, and haptic). If you gently move each of your baby’s toes at the moment you say the numbers, then you would also be adding kinesthetic information.

Incorporate Multisensory Learning to Make Daily Routines Multisensory Experiences
Think about the ways you spend time with your baby, then add more sensory information to these experiences that could help your baby learn. For example, when you are washing your baby, name your child’s body parts. Try to name them at the precise moment the cloth touches your baby’s skin. When you are talking about what your baby is seeing, hearing, touching, smelling, tasting, or about your child’s movements, carefully match your words to describe your child’s experience. In other words, if your baby is experiencing a flower, describe how the flower smells, looks, feels, and even how it sounds. Do this while your child is smelling the flower, looking at the flower, touching the flower, and listening for sounds as you and your baby move the flower.

Use Multisensory Learning to Acquire Languages
Allowing your baby to see and hear languages at the same time will give your babies more information compared to learning through one sensory system. Encourage your child to use touch, smell, taste, and to do physical actions related to the meanings of the words. Applying this multisensory approach to language acquisition allows your baby to learn English and other languages through more sensory systems.

Touch your nose! If a child touches his nose while hearing the word nose or seeing the word nose, that can be multisensory learning.

For example, you could draw your baby’s attention to your mouth while speaking. This allows your child to see and hear words as they are formed. It is even better to add touch and movement. Movement is sometimes called a sixth sense for babies since they gather so much information this way. If your baby does a physical action related to the word that involves touching, then your child should have even more brain connections related to the word. If the word is nose, your baby would have more multisensory information if all of the following occurred:

your baby sees and hears the word nose (visual and auditory info.)
your baby sees your nose (visual info.)
someone touches your baby’s nose (touch/haptic info.)
your baby touches his nose while looking into a mirror (kinesthetic, haptic, and visual info.)
your baby smells something with his nose (olfactory info.)
you describe and show what is happening as it happens (auditory and visual info.)

Edelman, G. M. (1987). Neural Darwinism. New York: Basic Books.

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