cortical

Examples of cortical in the following topics:

• Embryonic Development of the Brain

  • An example of tangential migration is the movement of Cajal-Retzius cells from the cortical hem to the superfitial part of cortical neuroepithelium.
  • Radial fibers (also known as radial glia) can translocate to the cortical plate and differentiate either into astrocytes or neurons.
  • An example of tangential migration is the movement of Cajal-Retzius cells from the cortical hem to the superfitial part of cortical neuroepithelium.
  • This is seen in multipolar cells, which are abundantly present in the cortical intermediate zone.

• Mapping the Primary Somatosensory Area

  • The cortical sensory homunculus is located in the postcentral gyrus and provides a representation of the body to the brain.
  • A cortical homunculus is a pictorial representation of the anatomical divisions of the primary motor cortex and the primary somatosensory cortex; it is the portion of the human brain directly responsible for the movement and exchange of sensory and motor information of the body.
  • This technique also allowed him to create maps of the sensory and motor cortices of the brain,  showing their connections to the various limbs and organs of the body.
  • 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.

• Phantom Limb Sensation

  • Ramachandran argued that the perception of being touched on different parts of the phantom limb was the perceptual correlate of cortical reorganization in the brain.
  • However, research published in 1995 by Flor et al. demonstrated that pain (rather than referred sensations) was the perceptual correlate of cortical reorganization.
  • In 1996, Knecht et al. published an analysis of Ramanchandran's theory that concluded that there was no topographic relationship between referred sensations and cortical reorganization in the primary cortical areas.
  • Recent research by Flor et al. suggests that non-painful referred sensations are correlated with a wide neural network outside the primary cortical areas.

• Gross Anatomy

  • There are two types of bone tissue: cortical and cancellous bone.
  • Cortical bone is compact bone, while cancellous bone is trabecular and spongy bone.
  • Cortical bone forms the extremely hard exterior while cancellous bone fills the interior.
  • They consist of a thin layer of cortical bone with cancellous interiorly.
  • These typically have a thin cortical layer with more cancellous bone in their tissue.

• Sensory Areas

  • A cortical homunculus is a physical representation of the human body located within the brain.
  • Areas with lots of sensory innervation, such as the fingertips and the lips, require more cortical area to process finer sensation.
  • Cortical Homunculus: A depiction of the human brain areas directly associated with the activity of a particular body part.

• Nephron: The Functional Unit of the Kidney

  • Eighty-five percent of nephrons are cortical nephrons, deep in the renal cortex; the remaining 15 percent are juxtamedullary nephrons, which lie in the renal cortex close to the renal medulla.
  • A nephron consists of three parts: a renal corpuscle, a renal tubule, and the associated capillary network, which originates from the cortical radiate arteries.

• Integration of Signals from Mechanoreceptors

  • Both primary somatosensory cortex and secondary cortical areas are responsible for processing the complex picture of stimuli transmitted from the interplay of mechanoreceptors.
  • Tactile-sense-related cortical neurons have receptive fields on the skin that can be modified by experience or by injury to sensory nerves, resulting in changes in the field's size and position.

• Association Areas

  • Associated cortical regions involved in vision, touch sensation, and non-speech movement are also shown.

• General Organization of the Somatosensory System

  • A cortical homunculus is the brain's physical representation of the human body; it is a neurological map of the anatomical divisions of the body.
  • Image representing the cortical sensory homunculus.

• Cholinergic Neurons and Receptors

  • As a result, these layer-specific effects of ACh might function to improve the signal-to-noise ratio of cortical processing.
  • At the same time, acetylcholine acts through nicotinic receptors to excite certain groups of inhibitory interneurons in the cortex that further dampen cortical activity.
  • Phasic increases of ACh during visual, auditory, and somatosensory stimulus presentations have been found to increase the firing rate of neurons in the corresponding primary sensory cortices.