Cross references:
Early Behavior
Amphioxus Amphioxus Behavior Amphioxus Nervous System Amphioxus Motor Nerves Ventral Motor Neurons Dorsal Motor Neurons Primary Motor Center Motor Nerve Organization Amphioxus Hormone-Nerve Interaction Amphioxus Muscles Amphioxus Fast-Slow Twitch Lamprey Locomotion Salamander Locomotion Subcortical Brain Although the Lamprey Nervous System is much more similar to ours, the Amphioxus Nervous System is interesting, so I'm going to start there. The long list of links in "Cross references", above, to pages in
Children of the Amphioxus is intended to provide general background to amphioxus locomotion. amphioxus locomotion - Google Search - 25,000 references NOTE: This article assumes that the amphioxus is predominately mobile. This disputes the view that the amphioxus remains buried in the sand for most of the time. amphioxus locomotion - Mozilla Yahoo Search Results - 48,000 references 2001 NOTE: amphioxus locomotion - PubMed - 13 references New perspectives on the evolution of protochordate sensory and locomotory systems, and the origin of brains and heads. Free PMC Article "Cephalochordates (i.e. amphioxus) are segmented and resemble vertebrates in having two distinct locomotory modes, slow for distance swimming and fast for escape, that depend on separate sets of motor neurons and muscle cells. The sense organs of both amphioxus and tunicate larvae serve essentially as navigational aids ..." "Similarities between amphioxus and tunicate sense organs are then most easily explained if distance swimming evolved before and escape behaviour after the two lineages diverged, leaving tunicates to adopt more passive means of avoiding predation." 2002 Dorsal Compartment Locomotory Control System (PubMed) http://www.ncbi.nlm.nih.gov/pubmed/11948671 See: Dorsal Motor Neurons . 2003 Ventral neurons in the anterior nerve cord ... I (PubMed) http://www.ncbi.nlm.nih.gov/pubmed/12833380 Please see: Ventral Motor Neurons . 2003 Ventral neurons in the anterior nerve cord of amphioxus larvae. II. Further data on the pacemaker circuit. (Goog) http://www3.interscience.wiley.com/journal/104528758/abstract or Please see:
Ventral Motor Neurons . 2006 Tuning and playing a motor rhythm: how metabotropic glutamate receptors orchestrate generation of motor patterns in the mammalian central nervous system (Goog) http://jp.physoc.org/content/572/2/323.full Full length HTML available online for free. Please see: Amphioxus Glutamate . 2008 My comment: The cholinergic gene locus in amphioxus: molecular characterization and developmental expression patterns. "Amphioxus has three types of motoneurons, ventral compartment (VC) motoneurons, which innervate the fast fibers of the myotome, dorsal compartment (DC) ones, which innervate the slow fibers, and visceral motoneurons, which innervate all other body muscles " Searching Google for "fast twitch muscles" yielded 1,120,000 claimed hits. Are human fast and slow twitch muscles innervated by different nerves? See: Muscle Innervation and Amphioxus Fast-Slow Twitch . |
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