somatosensory

Examples of somatosensory in the following topics:

• General Organization of the Somatosensory System

  • The somatosensory system is composed of the neurons that make sensing touch, temperature, and position in space possible.
  • The somatosensory system is distributed throughout all major parts of our body.
  • A somatosensory pathway will typically consist of three neurons: primary, secondary, and tertiary.
  • Somatosensory information involved with proprioception and posture is processed in the cerebellum.
  • The somatosensory system functions in the body’s periphery, spinal cord, and the brain.

• Somatic Sensory Pathways

  • The somatosensory pathway is composed of three neurons located in the dorsal root ganglion, the spinal cord, and the thalamus.
  • A somatosensory pathway will typically have three long neurons: primary, secondary, and tertiary.
  • In the spinal cord, the somatosensory system includes ascending pathways from the body to the brain .
  • The primary somatosensory area in the human cortex is located in the postcentral gyrus of the parietal lobe.
  • Somatosensory information involved with proprioception and posture also target an entirely different part of the brain, the cerebellum.

• Mapping the Primary Somatosensory Area

  • Typically, the area of the body corresponds to a point on the primary somatosensory cortex (postcentral gyrus).
  • Areas such as the appendages, digits, and face can draw their sensory locations upon the somatosensory cortex.
  • Areas that are finely controlled, such as the digits, have larger portions of the somatosensory cortex, whereas areas that are coarsely controlled, such as the trunk, have smaller portions.
  • The idea of the cortical homunculus was created by Wilder Penfield and serves as a rough map of the receptive fields for regions of primary somatosensory cortex.
  • The postcentral gyrus is located in the parietal lobe of the human cortex and is the primary somatosensory region of the human brain.

• Cutaneous Sensation

  • The somatosensory system is composed of the receptors and processing centers to produce the sensory modalities, such as touch and pain.
  • The somatosensory is the system of nerve cells that responds to changes to the external or internal state of the body, predominately through the sense of touch, but also by the senses of body position and movement.
  • Processing primarily occurs in the primary somatosensory area in the parietal lobe of the cerebral cortex.

• Sensory and Motor Tracts

  • The spinothalamic tract is a somatosensory tract and the corticospinal tract is a motor tract.
  • Somatosensory organization is divided into the dorsal column–medial lemniscus tract (the touch/proprioception/vibration sensory pathway) and the anterolateral system, or ALS (the pain/temperature sensory pathway).
  • However, connections to the somatosensory cortex suggest that the pyramidal tracts are also responsible for modulating sensory information from the body.

• Somatosensation: Pressure, Temperature, and Pain

  • The somatosensory system allows the human body to perceive the physical sensations of pressure, temperature, and pain.
  • The human sense of touch is known as the somatic or somatosensory system.
  • The somatosensory system uses specialized receptor cells in the skin and body to detect changes in the environment.
  • Sensory cell function in the somatosensory system is determined by location.
  • Summarize the stages of the somatosensory system in which physical stimuli are detected and processed

• Integration of Signals from Mechanoreceptors

  • The many types of somatosensory receptors work together to ensure our ability to process the complexity of stimuli that are transmitted.
  • Both primary somatosensory cortex and secondary cortical areas are responsible for processing the complex picture of stimuli transmitted from the interplay of mechanoreceptors.
  • In the somatosensory system, receptive fields are regions of the skin or of internal organs.

• Sensory Areas

  • The primary somatosensory cortex, located across the central sulcus and behind the primary motor cortex, is configured to generally correspond with the arrangement of nearby motor cells related to specific body parts.
  • For example, the right primary somatosensory cortex receives information from the left limbs, and the right visual cortex receives information from the left eye.
  • This somatotopic map has commonly been illustrated as a deformed human representation, the somatosensory homunculus, in which the size of different body parts reflects the relative density of their innervation.

• Somatic Sensory Pathways to the Cerebellum

  • It is part of the somatosensory system and runs in parallel with the dorsal spinocerebellar tract.
  • It is part of the somatosensory system and runs in parallel with the ventral spinocerebellar tract.
  • The anterior and posterior spinocerebellar tracts are the major somatosensory pathways communicating with the cerebellum.

• Thalamus

  • The ventral posterior nucleus is a key somatosensory relay, which sends touch and proprioceptive information to the primary somatosensory cortex.