--- abstract: 'The span of complexity in brains, between the simplest flatworms and the most advanced mammals is exceedingly great, measured by the number of different anatomical parts, physiological processes, sensory discriminations, and behavioral alternatives in the repertoire. Most evolution of brains has been adaptive radiation within the same grade of complexity. Distinct grades of complexity have appeared a dozen or more times and quite often in the retrograde direction. Advancement has not been inevitable or obviously advantageous in survival value but has happened - long before primates or mammals or vertebrates. Compare cuttlefish and the most advanced gastropods, bees and the best brine shrimp, primates and the most advanced reptiles known - all twigs with common branches. This repeated achievement of evolution has had all too little study in respect of the detailed listing of differences between major taxa of distinct grades of complexity. Connectivity at the level now known for the mammalian cortex is much needed in other classes, with estimates of reciprocity, intrinsic differentiation, dendritic parcellation and afferent and efferent connections, both locally and projecting to other centers, each done quantitatively to permit comparison. Physiological system organization, personality properties of neurons and circuits, proclivities and emergent phenomena at several integrative levels are sketchily known only for parts of a few systems. Examples are given of opportunities for new research that can more adequately characterize grades of brains.' altloc: [] chapter: ~ commentary: ~ commref: ~ confdates: ~ conference: ~ confloc: ~ contact_email: ~ creators_id: [] creators_name: - family: Bullock given: TH honourific: '' lineage: '' date: 2002 date_type: published datestamp: 2002-11-08 department: ~ dir: disk0/00/00/25/81 edit_lock_since: ~ edit_lock_until: ~ edit_lock_user: ~ editors_id: [] editors_name: [] eprint_status: archive eprintid: 2581 fileinfo: /style/images/fileicons/text_html.png;/2581/1/anaheim_29May02.htm full_text_status: public importid: ~ institution: ~ isbn: ~ ispublished: inpress issn: ~ item_issues_comment: [] item_issues_count: 0 item_issues_description: [] item_issues_id: [] item_issues_reported_by: [] item_issues_resolved_by: [] item_issues_status: [] item_issues_timestamp: [] item_issues_type: [] keywords: 'Neuroscience, neural complexity, neurology' lastmod: 2011-03-11 08:55:05 latitude: ~ longitude: ~ metadata_visibility: show note: ~ number: 4 pagerange: 317-329 pubdom: FALSE publication: Integrative And Comperative Biology publisher: ~ refereed: FALSE referencetext: |- Braitenberg, V. and A. Schüz 1998. Cortex : statistics and geometry of neuronal connectivity. : Springer, Berlin, New York 2nd edition Bullock, T. H. 1980. Reassessment of neural connectivity and its specification. In H. M. Pinsker and W. D. Willis Jr. (eds.), Information Processing in the Nervous System, pp. 199-220. Raven Press, New York. Bullock, T. H. 1983. Electrical signs of activity in assemblies of neurons: compound field potentials as objects of study in their own right. Acta Morphol. Acad. Sci. Hung. 31:39-62. Bullock, T.H. 1984. Ongoing compound field potentials from octopus brain are labile and vertebrate-like. Electroencephalogr. Clin. Neurophysiol. 57:473-483. Bullock, T.H. and E. Ba ar. 1988. Comparison of ongoing compound field potentials in the brains of invertebrates and vertebrates. Brain Res. Rev. 13:57-75. Bullock, T.H. 1992. Introduction to induced rhythms: a widespread, heterogeneous class of oscillations. In E. Ba ar and T.H. Bullock (eds.), Induced Rhythms in the Brain, pp 1-26. Birkhäuser, Boston. Bullock, T.H. and J. Z. Achimowicz.1994. A comparative survey of oscillatory brain activity, especially gamma-band rhythms. In C. Pantev, T. Elbert and B. Lütkenhöner (eds.), Oscillatory Event-Related Brain Dynamics, (NATO A: Life Sciences series, vol. 271), pp. 11-26. Plenum Press, New York. Bullock, T. H., McClune M. C., Achimowicz, J. Z., Iragui- Madoz, V. J., Duckrow, R. B. and S. S. Spencer. 1995a. Temporal fluctuations in coherence of brain waves. Proc. Natl. Acad. Sci. U.S.A. 92:11568-11572. Bullock, T. H., McClune, M. C., Achimowicz, J. Z., Iragui- Madoz V. J., Duckrow, R. B. and S. S. Spencer. 1995b. EEG coherence has structure in the millimeter domain: subdural and hippocampal recordings from epileptic patients. Electroencephalogr. Clin. Neurophysiol. 95:161-177. Bullock, T. H., McClune, M. C. and J. Z. Achimowicz. 1995c. EEG coherence as a measure of synchrony shows fine structure in space and time. Abstr. of the Fourth IBRO World Cong. of Neurosci., Kyoto, Japan. p 494 Bullock, T. H., Achimowicz, J. Z., Duckrow, R. B., Spencer, S. S. and V. J. Iragui-Madoz.1997. Bicoherence of intracranial EEG in sleep, wakefulness and seizures. Electroencephalogr. Clin. Neurophysiol. 103:661-678. Felleman, D J; and D.C. Van Essen 1991 Distributed hierarchical processing in the primate cerebral cortex. Cerebral Cortex, 1 :1-47 Stephan, K. E., Kamper, L., Bozkurt, A., Burns, G. A. P. C., Young, M. P., and R. Koetter 2001 Advanced database methodology for the Collation of Connectivity data on the Macaque brain (CoCoMac). Phil. Trans. Roy. Soc., London B 356 (1412): 1159- 1186. Wicht, W. and R.G. Northcutt. 1992. The forebrain of the Pacific Hagfish: a cladistic reconstruction of the ancestral craniate forebrain. Brain Behav. Evol. 40:25-64. relation_type: [] relation_uri: [] reportno: ~ rev_number: 8 series: ~ source: ~ status_changed: 2007-09-12 16:45:53 subjects: - neuro-physio succeeds: ~ suggestions: ~ sword_depositor: ~ sword_slug: ~ thesistype: ~ title: 'Grades in neural complexity: how large is the span?' type: journalp userid: 479 volume: 42