Alfred Lee

© 2015 Elsevier Ireland Ltd.The fornix is the primary subcortical output fiber system of the hippocampal formation. In children with 22q11.2 deletion syndrome, hippocampal volume reduction has been commonly reported, but few studies as yet have evaluated the integrity of the fornix. Therefore, we investigated the fornix of 45 school-aged children with 22q11.2DS and 38 matched typically developing children. Probabilistic diffusion tensor imaging tractography was used to reconstruct the body of the fornix in each child[U+05F3]s brain native space. Compared with children, significantly lower fractional anisotropy and higher radial diffusivity was observed bilaterally in the body of the fornix in children with 22q11.2DS. Irregularities were especially prominent in the posterior aspect of the fornix where it emerges from the hippocampus. Smaller volumes of the hippocampal formations were also found in the 22q11.2DS group. The reduced hippocampal volumes were correlated with lower fornix FA and higher fornix RD in the right hemisphere. Our findings provide neuroanatomical evidence of disrupted hippocampal connectivity in children with 22q11.2DS, which may help to further understand the biological basis of spatial impairments, affective regulation, and other factors related to the ultra-high risk for schizophrenia in this population.

The present study is an attempt to represent a post-metaphysical thinking that Nietzsche ushered in as a reconstructive ethics. The argument presented here is that the key to such a formulation of ethics resides in Heidegger's 'fundamental ontology' as 'original ethics'. Such a formulation that is grounded in an ontology deconstructs that subjectivity and rationality which has been posited by traditional ethics or moral reasoning. The outcome of such a restructuring of reason in Western thinking ushers in an historical essence that problematizes thinking in terms of an issue that Heidegger raised regarding ground in reason and thinking itself. The vantage point of viewing such a development in ethics is that of a transcendence in conventional Western thinking, as destroyed by Nietzsche's metaphysics and thematized in Heidegger's ontology. Chapter One establishes the framework of thematizing ethics in a post-metaphysical era where subjectivity and rationality have become problematic in terms of an existential selfhood and an ontology of reason. Chapter Two establishes the framework of constructing a metaphysical ethics as that which is grounded in a deconstructed 'moral' self in ethics as moral reasoning. Chapter Three focuses on history as that essence and ground in thinking where the problem of truths is thematized as that which deconstructs subjectivity and reason. Chapter Four focuses on thinking as an ontological thematic in Heidegger which surpasses Nietzsche's metaphysics. The outcome of such a thinking is an ethics of existence, as that which problematizes conventional ethics as moral reasoning. The issue presented here is that of ground, and hence ontology and existence, in a metaphysical ethics. Chapter Five concludes by pointing out that such metaphysical thinking which has been presented in this study represents a reconstruction of Western thinking as ethics. The existential and ontological thematic of ground in thinking establishes existence as that essence of thinking and ethics which has been lost in conventional Western philosophical thinking.