Jeff Schwartz

Neuropsychological research on the neural basis of behaviour generally posits that brain mechanisms will ultimately suffice to explain all psychologically described phenomena. This assumption stems from the idea that the brain is made up entirely of material particles and fields, and that all causal mechanisms relevant to neuroscience can therefore be formulated solely in terms of properties of these elements. Thus, terms having intrinsic mentalistic and/or experiential content (e.g. ‘feeling’, ‘knowing’ and ‘effort’) are not included as primary causal factors. This theoretical restriction is motivated primarily by ideas about the natural world that have been known to be fundamentally incorrect for more than three-quarters of a century. Contemporary basic physical theory differs profoundly from classic physics on the important matter of how the consciousness of human agents enters into the structure of empirical phenomena. The new principles contradict the older idea that local mechanical processes alone can account for the structure of all observed empirical data. Contemporary physical theory brings directly and irreducibly into the overall causal structure certain psychologically described choices made by human agents about how they will act. This key development in basic physical theory is applicable to neuroscience, and it provides neuroscientists and psychologists with an alternative conceptual framework for describing neural processes. Indeed, owing to certain structural features of ion channels critical to synaptic function, contemporary physical theory must in principle be used when analysing human brain dynamics. The new framework, unlike its classic-physics-based predecessor, is erected directly upon, and is compatible with, the prevailing principles of physics. It is able to represent more adequately than classic concepts the neuroplastic mechanisms relevant to the growing number of empirical studies of the capacity of directed attention and mental effort to systematically alter brain function..

Although molecular systematists may use the terminology of cladism, claiming that the reconstruction of phylogenetic relationships is based on shared derived states , the latter is not the case. Rather, molecular systematics is based on the assumption, first clearly articulated by Zuckerkandl and Pauling , that degree of overall similarity reflects degree of relatedness. This assumption derives from interpreting molecular similarity between taxa in the context of a Darwinian model of continual and gradual change. Review of the history of molecular systematics and its claims in the context of molecular biology reveals that there is no basis for the “molecular assumption.”

We propose that the sudden emergence of metazoans during the Cambrian was due to the appearance of a complex genome architecture that was capable of computing. In turn, this made defining recursive functions possible. The underlying molecular changes that occurred in tandem were driven by the increased probability of maintaining duplicated DNA fragments in the metazoan genome. In our model, an increase in telomeric units, in conjunction with a telomerase-negative state and consequent telomere shortening, generated a reference point equivalent to a non-reversible counting mechanism.

I attempt to raise questions regarding elements of systematics—primarily in the realm of phylogenetic reconstruction—in order to provoke discussion on the current state of affairs in this discipline, and also evolutionary biology in general: e.g., conceptions of homology and homoplasy, hypothesis testing, the nature of and objections to Hennigian “phylogenetic systematics”, and the schism between Darwinian descendants of the “modern evolutionary synthesis” and their supposed antagonists, cladists and punctuationalists

Although the construction of neo-Darwinism grew out of Thomas Hunt Morgan's melding of Darwinism and Mendelism, his evidence did not soley support a model of gradual change. To the contrary, he was confronted with observations that could have led him to a more "evo-devo" understanding of the emergence of novel features. Indeed, since Morgan was an embryologist before he became a fruit-fly geneticist, one would have predicted that the combination of these two lines of research would have resulted in early formulations of concepts relevant to evolutionary developmental biology. It is thus of interest to review Morgan's thought processes and arguments for at first rejecting both Darwinism and Mendelism, and then for later dismissing data that would have yielded a model of rapid morphological change in favor of a model of change based on the accumulation of minor mutations and their morphological consequences.

Purpose: To assess noninvasive optical coherence tomography and optical Doppler tomography for early detection and evaluation of chemotherapy-induced oral mucositis. Experimental Design: Cheek pouches of 10 Syrian golden hamsters were imaged using OCT/ODT during development of chemotherapy-induced mucositis. I.p. injections of 5-fluorouracil and mechanical irritation induced oral lesions. At 2, 4, 7, and 11 days, one hamster was sacrificed and processed for histopathology. OCT images were visually examined; ODT results were semiquantified. Imaging data were compared with histologic findings. Results: During the development of mucositis, OCT/ODT identified the following events: change in epithelial thickness, loss of surface keratinized layer continuity, loss of epithelial and submucosal integrity, changes in axial blood flow velocity, and changes in blood vessel size. The semiquantitative imaging-based scoring system identified the severity of mucositis as defined by histopathology. The combination of imaging criteria used allowed for the detection of early, intermediate, and late mucositic changes. Imaging data gave higher scores compared with clinical scores early on, suggesting that the imaging-based diagnostic scoring was more sensitive to early mucositic change than the clinical scoring system. Once mucositis was established, imaging and clinical scores converged. Conclusion: OCT/ODT identified chemotherapy-induced oral changes before their clinical manifestation, and the proposed scoring system for oral mucositis was validated for the semiquantification of mucositic change. © 2007 American Association for Cancer Research.