Spatial navigation deficits — overlooked cognitive marker for preclinical Alzheimer disease?

Detection of incipient Alzheimer disease (AD) pathophysiology is critical to identify preclinical individuals and target potentially disease-modifying therapies towards them. Current neuroimaging and biomarker research is strongly focused in this direction, with the aim of establishing AD fingerprints to identify individuals at high risk of developing this disease. By contrast, cognitive fingerprints for incipient AD are virtually non-existent as diagnostics and outcomes measures are still focused on episodic memory deficits as the gold standard for AD, despite their low sensitivity and specificity for identifying at-risk individuals. This Review highlights a novel feature of cognitive evaluation for incipient AD by focusing on spatial navigation and orientation deficits, which are increasingly shown to be present in at-risk individuals. Importantly, the navigation system in the brain overlaps substantially with the regions affected by AD in both animal models and humans. Notably, spatial navigation has fewer verbal, cultural and educational biases than current cognitive tests and could enable a more uniform, global approach towards cognitive fingerprints of AD and better cognitive treatment outcome measures in future multicentre trials. The current Review appraises the available evidence for spatial navigation and/or orientation deficits in preclinical, prodromal and confirmed AD and identifies research gaps and future research priorities

Transformative sensemaking: Development in Whose Image? Keyan Tomaselli and the semiotics of visual representation

The defining and distinguishing feature of homo sapiens is its ability to make sense of the world, i.e. to use its intellect to understand and change both itself and the world of which it is an integral part. It is against this backdrop that this essay reviews Tomaselli's 1996 text, Appropriating Images: The Semiotics of Visual Representation/ by summarizing his key perspectives, clarifying his major operational concepts and citing particular portions from his work in support of specific perspectives on sense-making. Subsequently, this essay employs his techniques of sense-making to interrogate the notion of "development". This exercise examines and confirms two interrelated hypotheses: first, a semiotic analysis of the privileged notion of "development" demonstrates its metaphysical/ ideological, and thus limiting, nature especially vis-a-vis the marginalized, excluded, and the collective other, the so-called Developing Countries. Second, the interrogative nature of semiotics allows for an alternative reading and application of human potential or skills in the quest of a more humane social and global order, highlighting thereby the transformative implications of a reflexive epistemology.Web of Scienc

ECONOMIC HISTORY AND THE THEORY OF PRIMITIVE SOCIO-ECONOMIC DEVELOPMENT

This dissertation analyzes and critiques Marxist and non-Marxist economic history, in which primitive societies are treated as devoid of history and development. The dissertation argues that in both Marxist and non-Marxist historical writing, the treatment of primitive societies as lacking an historical dynamic is linked to the use of various kinds of essentialist and teleological discourses. Chapter I is a critical presentation of the forms of writing, such as historical narrative and realism, employed by historians and social scientists who produce these discourses. This chapter begins to present the concepts of an anti-essentialist Marxist discourse, as developed by Althusser, Hindess and Hirst, and Resnick and Wolff, in contradistinction to essentialist and teleological discourses. Chapter I argues that an anti-essentialist Marxism, with the concepts of class and over-determination as its entry point, can produce concepts of primitive history and development. Chapter II continues the presentation of basic concepts, such as necessary and surplus labor, fundamental and subsumed class processes and positions, social formation, overdetermination, transition, and development, that comprise an anti-essentialist Marxist discourse. Chapter III reviews and critiques the Marxist concept of primitive communism frequently used to analyze the socio-economic structure of primitive societies. Chapter III shows how most writing on primitive communism treats primitive communism as a signifier for the absence of history and development, as a discursive representation of the concept of historical origins and/or ends, and as a social scientific type in which primitivism is the central defining characteristic. These treatments, exemplified in the works of Anderson, Godelier, Hindess and Hirst, Leacock, Rey, and others, make problematic the theorization of primitive history and development. By contrast, Marx\u27s treatment of pre-capitalist forms of the commune in the Grundrisse provides the basis for an alternative formulation of primitive communism produced with the concepts primitive communal fundamental and subsumed class processes and non-class processes and overdetermination. Through the use of these concepts, Marx\u27s presentation in the Grundrisse can be read as a demonstration of how an anti-essentialist Marxism theorizes history and socio-economic development in primitive societies