Amphioxus Evolution

Cross references:  Amphioxus    Amphioxus Hormones    Amphioxus Neuropeptides  
Amphioxus Neurotransmitters   Amphioxus Receptors
Amphioxus Nervous System   

    from:  Amphioxus PDFs       I got the PDF through the library.    

The nervous system of amphioxus: structure, development, and evolutionary significance    

    from:  Amphioxus PDFs       I got the PDF through the library.    

Amphioxus molecular biology: insights into vertebrate evolution and developmental mechanisms (NRC) - 2005 
Only abstract available online for free.  I got the PDF through the library. 
The cephalochordate amphioxus is the best available proxy for the last common invertebrate ancestor of the vertebrates. During the last decade, the developmental genetics of amphioxus have been extensively examined for insights into the evolutionary origin and early evolution of the vertebrates. Comparisons between expression domains of homologous genes in amphioxus and vertebrates have strengthened proposed homologies between specific body parts. Molecular genetic studies have also highlighted parallels in the developmental mechanisms of amphioxus and vertebrates. In both groups, a similar nested pattern of Hox gene expression is involved in rostrocaudal patterning of the neural tube, and homologous genes also appear to be involved in dorsoventral neural patterning."  

Evolution of the brain developmental plan: Insights from agnathans. 
    Free full text (many informative diagrams)  


Lacalli TC. 
Philos Trans R Soc Lond B Biol Sci. 2001 Oct 29;356(1414):1565-72. Review.PMID: 11604123

New perspectives on the evolution of protochordate sensory and locomotory systems, and the origin of brains and heads.
Related articles
Free article 
PDF can  be read, but not copied. 
    New perspectives on the evolution of protochordate...(PubMed)$=relatedreviews&logdbfrom=pubmed 
"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.

    Also:  Amphioxus Fast-Slow Twitch   and Amphioxus Locomotion


Lacalli TC.
Int J Biol Sci. 2006;2(3):104-9. Epub 2006 May 5. Review.PMID: 16763669

Prospective protochordate homologs of vertebrate midbrain and MHB, with some thoughts on MHB origins.
Related articles
Free article

Lacalli: 1994
Apical Organs, Epithelial Domains, and the Origin of the Chordate Central Nervous System 
Link to abstract only.  I'm not sure this is relevant to psychology.    

Holland: 1999
Current Opinion in Neurobiology, Volume 9, Issue 5, 1 October 1999, Pages 596-602
Linda Z Holland, Nicholas D Holland

Chordate origins of the vertebrate central nervous system
Link to abstract only, but I have the PDF. 

Lacalli: 1996 
Landmarks and Subdomains in the Larval Brain of Branchiostoma: Vertebrate Homologs and Invertebrate Antecedents 
no electronic version available - Israel Journal of Zoology 
I have hard copy. 

EvoDevo | Full text | Genome-wide survey and expression analysis of the bHLH-PAS genes in the amphioxus Branchiostoma floridae reveal both conserved and diverged expression patterns between cephalochordates and vertebrates