synaptic plasticity

Examples of synaptic plasticity in the following topics:

• Embryonic Development of the Brain

  • Neural activity and sensory experience will mediate formation of new synapses, as well as synaptic plasticity, which will be responsible for refinement of the nascent neural circuits.

• Modulation of Movement by the Cerebellum

  • Several theoretical models have been developed to explain sensorimotor calibration in terms of synaptic plasticity within the cerebellum.
  • Although a full understanding of cerebellar function remains elusive, at least four principles are identified as important: 1) feedforward processing, 2) divergence and convergence, 3) modularity, and 4) plasticity.
  • Plasticity: The synapses between parallel fibers and Purkinje cells, and the synapses between mossy fibers and deep nuclear cells, are both susceptible to modification of their strength.

• Cholinergic Neurons and Receptors

  • Acetylcholine is a neurotransmitter in the central and peripheral nervous systems affecting plasticity, arousal, and reward.
  • In the central nervous system, ACh has a variety of effects as a neuromodulator of plasticity, arousal, and reward.
  • This enzyme is abundant in the synaptic cleft, and its role in rapidly clearing free acetylcholine from the synapse is essential for proper muscle function.

• The Synapse

  • The presynaptic neuron contains a chemical called a neurotransmitter that is packaged into synaptic vesicles clustered beneath the membrane in the axon terminal.
  • The neurotransmitter is released into and diffuses across the synaptic cleft, where it binds to specific receptors in the membrane on the postsynaptic side of the synapse.
  • A: Neuron (Presynaptic) B: Neuron (Postsynaptic)MitochondriaSynaptic vesicle full of neurotransmitterAutoreceptorSynaptic cleftNeurotransmitter receptorCalcium ChannelFused vesicle releasing neurotransmitterNeurotransmitter re-uptake pump

• Types of Neurotransmitters by Function

  • Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane in the axon terminal on the presynaptic side of a synapse.
  • They are released into and diffuse across the synaptic cleft, where they bind to specific receptors in the membrane on the postsynaptic side of the synapse.
  • Once released, acetylcholine binds to post-synaptic receptors and is degraded by acetylcholinesterase.

• Peripheral Motor Endings

  • This influx of Ca2+ causes neurotransmitter-containing vesicles to dock and fuse to the presynaptic neuron's cell membrane, which results in the emptying of the vesicle's contents (acetylcholine) into the synaptic cleft; this process is known as exocytosis.
  • Acetylcholine diffuses into the synaptic cleft and binds to the nicotinic acetylcholine receptors located on the motor end plate.
  • Detailed view of a neuromuscular junction: 1) Presynaptic terminal; 2) Sarcolemma; 3) Synaptic vesicle; 4) Nicotinic acetylcholine receptor; 5) Mitochondrion.

• Neuroglia of the Central Nervous System

  • Their numerous radiating processes cling to neurons and their synaptic endings.
  • They also regulate the external chemical environment of neurons by removing excess ions and recycling neurotransmitters released during synaptic transmission.

• Rhinoplasty

  • Rhinoplasty, a nose job, is a plastic surgery procedure for correcting and reconstructing the form of the nose.
  • Rhinoplasty, a nose job, is a plastic surgery procedure for correcting and reconstructing the form, restoring the functions, and aesthetically enhancing the nose by resolving nasal trauma (blunt, penetrating, blast), congenital defect, respiratory impediment, and a failed primary rhinoplasty.
  • The plastic surgical correction of congenital and acquired abnormalities of the nose restores functional and aesthetic properties by the surgeon's manipulations of the nasal skin, the subcutaneous (underlying) cartilage-and-bone support framework, and the mucous membrane lining.
  • Technically, the plastic surgeon's incisional approach classifies the nasal surgery either as an open rhinoplasty or as a closed rhinoplasty procedure.
  • The open rhinoplasty approach in turn affords the plastic surgeon the advantages of ease in securing the grafts (skin, cartilage, bone) and, most important, in seeing the nasal cartilages proper, and so make the appropriate diagnosis.

• Withdrawing Blood

  • A blood collection tube is a sterile glass or plastic tube with a closure.
  • The vein is first punctured with the hypodermic needle which is carried in a translucent plastic holder.
  • The test tubes are covered with a color-coded plastic cap .
  • They often include additives that mix with the blood when collected, and the color of the tube's plastic cap indicates which additives that tube contains.
  • The plastic caps are opaque for tubes with a normal vacuum.

• Adrenal Medulla

  • Chromaffin cells are the neuroendocrine cells found in the medulla, they are modified post-synaptic sympathetic neurons that receive sympathetic input.