Sensory System Information
A sensory system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory receptors, neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for vision, hearing, somatic sensation (touch), taste and olfaction (smell). In short, senses are transducers from the physical world to the realm of the mind.
The receptive field is the specific part of the world to which a receptor organ and receptor cells respond. For instance, the part of the world an eye can see, is its receptive field; the light that each rod or cone can see, is its receptive field.[1] Receptive fields have been identified for the visual system, auditory system and somatosensory system, so far.
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Stimulus
Sensory systems code for four aspects of a stimulus; type (modality), intensity, location, and duration. Arrival time of a sound pulse and phase differences of continuous sound are used for localization of sound sources. Certain receptors are sensitive to certain types of stimuli (for example, different mechanoreceptors respond best to different kinds of touch stimuli, like sharp or blunt objects). Receptors send impulses in certain patterns to send information about the intensity of a stimulus (for example, how loud a sound is). The location of the receptor that is stimulated gives the brain information about the location of the stimulus (for example, stimulating a mechanoreceptor in a finger will send information to the brain about that finger). The duration of the stimulus (how long it lasts) is conveyed by firing patterns of receptors. These impulses are transmitted to the brain through afferent neurons.
Modality
A stimulus modality (sensory modality) is a type of physical phenomenon that can be sensed. Examples are temperature, taste, sound, and pressure. The type of sensory receptor activated by a stimulus plays the primary role in coding the stimulus modality.
In the memory-prediction framework, Jeff Hawkins mentions a correspondence between the six layers of the cerebral cortex and the six layers of the optic tract of the visual system. The visual cortex has areas labelled V1, V2, V3, V4, V5, MT, IT, etc. Thus Area V1 mentioned below, is meant to signify only one class of cells in the brain, for which there can be many other cells which are also engaged in vision.
Hawkins lays out a scheme for the analogous modalities of the sensory system. Note that there can be many types of senses, some not mentioned here. In particular, for humans, there will be cells which can be labelled as belonging to V1, V2 A1, A2, etc.:
V1 (vision)
The human eye is the first element of a sensory system: in this case, vision, for the visual system.Visual Area 1, or V1, is used for vision, via the visual system to the primary visual cortex.
earA1 (auditory - hearing)
Auditory Area 1, or A1, is for hearing, via the auditory system, the primary auditory cortex.
S1 (somatosensory - touch and proprioception)
Somatosensory Area 1, or S1, is for touch and proprioception in the somatosensory system. The somatosensory system feeds the Brodmann Areas 3, 1 and 2 of the primary somatosensory cortex. But there are also pathways for proprioception (via the cerebellum), and motor control (via Brodmann area 4).
tongueG1 (gustatory - taste)
Gustatory Area 1, or G1, is used for taste. Taste does not refer to the flavor of food, because the flavor of the food refers to the odor. The five qualities of taste include sourness, bitterness, sweetness, saltiness, and recently umami(a Japanese for "good taste").
O1 (olfactory - smell)
Olfactory Area 1, or O1, is used for smell. In contrast to vision and hearing, the olfactory bulbs are not cross-hemispheric; the right bulb connects to the right hemisphere and the left bulb connects to the left hemisphere.
Human sensory system
The Human sensory system consists of the following sub-systems:
- Visual system consists of the photoreceptor cells, optic nerve, and V1.
- Auditory system
- Somatosensory system consists of the receptors, transmitters (pathways) leading to S1, and S1 that experiences the sensations labelled as touch or pressure, temperature (warm or cold), pain (including itch and tickle), and the sensations of muscle movement and joint position including posture, movement, and facial expression (collectively also called proprioception).
- Gustatory system
- Olfactory system
Human sensory receptors are:
Diseases
Amblyopia Anacusis Astigmatism (eye) Cataract Colour blindness Deafness Hyperopia
Disability-adjusted life year for sense organ diseases per 100,000 inhabitants in 2002.[2] no data less than 200 200-400 400-600 600-800 800-1000 1000-1200 1200-1400 1400-1600 1600-1800 1800-2000 2000-2300 more than 2300See also
- Sensor
- Sensory neuroscience
- Wikibook "Sensory Systems"
References
- ^ Kolb & Whishaw: Fundamentals of Human Neuropsychology (2003)
- ^ "Mortality and Burden of Disease Estimates for WHO Member States in 2002" (xls). World Health Organization. 2002. http://www.who.int/entity/healthinfo/statistics/bodgbddeathdalyestimates.xls.
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Times of India
Sukanya Dass, spokesperson of GD Birla Memorial School and Ashok Hall Girls Residential School, Ranikhet, said, We employ methods like multi- sensory ...
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Sensory Development - Touch, Taste And Smell, Movement Sensations, Auditory System, Visual System, Sensory Systems In Concert - Body Position Sense
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Thu, 14 Oct 2010 18:22:38 PDT
are two, or there's two primary systems that I evaluate, brain systems I evaluate. The first has to do with sensory motor processing systems ... ehow.com.
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Q. Lateral Line System Tympanic Membrane Echolocation Jacobsons organ Which one of these I am really confused! Please help!!!
Asked by chiffonqueen16 - Sun Mar 4 13:33:35 2007 - Biology - 1 Answers - Comments
A. Lateral Line System. It is the electrially sensitive cord of nerves running just below the skin along the dorsal side of the shark. It detects electrical impulses given of by animals so nothing is safe, the electrical impluses from your brain to your heart to pump can give you away. Mostly it is used for detecting fish when the are wounded and thrashing, or when they are swimming. They use this instead of their sight, as their sight is pretty bad. Their other strong organ is smell. They have a sense of smell so powerful they can detect blood at one part per billion, they can also smell it up to a mile away! They are pretty fascinating animals. And they are fish, not many people think of them as that, but they are.
Answered by Alex - Tue Mar 6 22:47:13 2007