Month: October 2017

Kurt Lewin

Gestalt Psychology, even though it no longer survives as a separate entity, has had an enormous impact.  Two people in particular lead the way in introducing it into other aspects of psychology:  Kurt Goldstein and Kurt Lewin.

Kurt Lewin was born September 9, 1890, in Mogilno, Germany.  He received his PhD from the University of Berlin under Stumpf.  After military service, he returned to Berlin where he worked with Wertheimer, Koffka, and Köhler.

He went to the U.S. as a guest lecturer at Stanford and Cornell, and took a position at the University of Iowa in 1935.  In 1944, he created and directed the Research Center for Group Dynamics at MIT.  He died in 1947, just beginning his work there.

Lewin created a topological theory that expressed human dynamics in the form of a map representing a person’s life space.  The map is patterned with one’s needs, desires, and goal, and vectors or arrows indicated the directions and strengths of these forces — all operating as a Gestalt.

This theory inspired any number of psychologists in the U.S., most particularly those in social psychology.  Among the people he influenced were Muzafer Sherif, Solomon Asch, and Leon Festinger.

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Kurt Goldstein

The other person was Kurt Goldstein.  Born in 1878, he received his MD from the University of Breslau in 1903.  He went to teach at the Neurological Institute of the University of Frankfurt, where he met the founders of Gestalt psychology.

He went to Berlin to be a professor there, and then went on to New York City in 1935.  There, he wrote The Organism in 1939, and later Human Nature in the Light of Pathology in 1963.  He died in 1965.

Golstein developed a holistic view of brain function, based on research that showed that people with brain damage learned to use other parts of their brains in compensation.  He extended his holism to the entire organism, and postulated that there was only one drive in human functioning, and coined the term self-actualization.  Self-preservation, the usual postulated central motive, he said, is actually pathological!

Goldstein and his idea of self-actualization influence quite a few young personality theorists and therapists.  Among them would be Gordon Allport, Carl Rogers, and Abraham Maslow, founders of the American humanistic psychology movement.

Action Research and Learning Circles

Action research is conducted in the workplace with others. It is a collaborative process. But, also, the doing of action research is more effective when action researchers can benefit from the help of a community of action researchers. The Center for Collaborative Action Research is part of a process of developing the community of action researchers for each cadre. In our program, action researchers carry out their work in learning circles—a structure for organizing group interaction. Combining this collaborative structure with the action research process is an effective way to provide high levels of support for action researchers as they design their action and engage in the process of studying the outcomes.

More recently it has been demonstrated that a distinct subset of var genes are highly transcribed following selection on human brain endothelial cells and that these same distinct subtypes are associated with cerebral malaria (Aird 2014; Cunnington 2013; Smith 2013). This tissue specific expression of particular var genes implies that different tissues are selecting out different parasite populations based on the particular PfEMP1 being expressed on the surface of the infected erythrocyte.

Although sequestration offers many advantages to the parasite, the expression of antigens on the surface of the infected erythrocyte provides a target for the host immune system. The parasite counters the host immune response by expressing antigenically distinct PfEMP1 molecules on the erythrocyte surface. This allows the parasite to avoid clearance by the host immune system, but yet maintain the cytoadherent phenotype. This antigenic switching may occur as frequently as 2% per generation in the absence of immune pressure (Roberts 1992). The molecular mechanism of antigenic switching is not known. Experimental evidence indicates that the mechanism is not associated with duplicative transposition into specific expression-linked sites as found in African trypanosomes. Only a single var gene is expressed at a time (i.e., allelic exclusion). The non-expressed genes are kept silent by proteins which bind to the promoter region. A gene can become activated by repositioning to a particular location in the nucleus and is associated with chromatin modification. This expression spot can only accommodate a single active gene promoter. Thus the var promoter is sufficient for both the silencing and the mono-allelic transcription of a PfEMP1 allele (Voss 2006; Guizetti 2013).

Summary

• The malarial parasite modifies the erythrocyte by exporting proteins into the host cell.
• One such modification is the expression of PfEMP1 on the erythrocyte surface which functions as the cytoadherent ligand.
• The binding of this ligand to receptors on host endothelial cells promotes sequestration and allows the infected erythrocyte to avoid the spleen.
• Numerous PfEMP1 genes (i.e., the var gene family) provide the parasite with a means to vary the antigen expressed on the erythrocyte surface.
• This antigenic variation also correlates with different cytoadherent phenotypes.