Phantom Sensations: What's a Brain to Do? A Critical Review of the Re-mapping Hypothesis

I will review the most widely held account of phantom sensations; the “re-mapping hypothesis.” According to the re-mapping hypothesis, amputation is followed by significant neural reorganization that, over time, restores the alignment between the brain’s representation of and the actual condition of the body. Implicit in the re-mapping hypothesis is the view that the brain’s primary function is to accurately represent the body. In response, I propose an alternative theory, the “preservation hypothesis.” The preservation hypothesis argues that the primary function of the brain is to preserve the entirety of the brain’s structures and functional capacities. While these issues concern empirical matters, assessing our views on the subject discloses deeply held assumptions regarding the brain’s primary function; does the brain operate to provide an accurate representation of the body? Or, does the brain operate solely to preserve its structures and functional capacities in their entirety

Fcgamma receptor-mediated phagocytosis in macrophages lacking the Src family tyrosine kinases Hck, Fgr, and Lyn.

Macrophage Fcgamma receptors (FcgammaRs) mediate the uptake and destruction of antibody-coated viruses, bacteria, and parasites. We examined FcgammaR signaling and phagocytic function in bone marrow-derived macrophages from mutant mice lacking the major Src family kinases expressed in these cells, Hck, Fgr, and Lyn. Many FcgammaR-induced functional responses and signaling events were diminished or delayed in these macrophages, including immunoglobulin (Ig)G-coated erythrocyte phagocytosis, respiratory burst, actin cup formation, and activation of Syk, phosphatidylinositol 3-kinase, and extracellular signal-regulated kinases 1 and 2. Significant reduction of IgG-dependent phagocytosis was not seen in hck(-)(/)-fgr(-)(/)- or lyn(-)(/)- cells, although the single mutant lyn(-)(/)- macrophages did manifest signaling defects. Thus, Src family kinases clearly have roles in two events leading to FcgammaR-mediated phagocytosis, one involving initiation of actin polymerization and the second involving activation of Syk and subsequent internalization. Since FcgammaR-mediated phagocytosis did occur at modest levels in a delayed fashion in triple mutant macrophages, these Src family kinases are not absolutely required for uptake of IgG-opsonized particles

Antigen Complexed with a TLR9 Agonist Bolsters c-Myc and mTORC1 Activity in Germinal Center B Lymphocytes.

The germinal center (GC) is the anatomical site where humoral immunity evolves. B cells undergo cycles of proliferation and selection to produce high-affinity Abs against Ag. Direct linkage of a TLR9 agonist (CpG) to a T-dependent Ag increases the number of GC B cells. We used a T-dependent Ag complexed with CpG and a genetic model for ablating the TLR9 signaling adaptor molecule MyD88 specifically in B cells (B-MyD88- mice) together with transcriptomics to determine how this innate pathway positively regulates the GC. GC B cells from complex Ag-immunized B-MyD88- mice were defective in inducing gene expression signatures downstream of c-Myc and mTORC1. In agreement with the latter gene signature, ribosomal protein S6 phosphorylation was increased in GC B cells from wild-type mice compared with B-MyD88- mice. However, GC B cell expression of a c-Myc protein reporter was enhanced by CpG attached to Ag in both wild-type and B-MyD88- mice, indicating a B cell-extrinsic effect on c-Myc protein expression combined with a B cell-intrinsic enhancement of gene expression downstream of c-Myc. Both mTORC1 activity and c-Myc are directly induced by T cell help, indicating that TLR9 signaling in GC B cells either enhances their access to T cell help or directly influences these pathways to further enhance the effect of T cell help. Taken together, these findings indicate that TLR9 signaling in the GC could provide a surrogate prosurvival stimulus, "TLR help," thus lowering the threshold for selection and increasing the magnitude of the GC response

Club Ratios: A Four-Year Trend Analysis

This article is based on research of the United States club industry conducted over the four-year period of 2003-2006. Twenty ratios were reported, covering the five general classes of financial ratios. The ratio results suggested that 2003 was a banner year for the club industry

Satisfaction: Is Money Everything?

When people are asked whether they are satisfied with their jobs or careers, the first item that comes to mind, most of the time, is money. Then other factors such as advancement, work hours, autonomy, flexibility, etc. are soon added to the total equation. In this study, 140 financial and technology professionals in the lodging industry shared their satisfaction level and perceived importance of carious attributes of their career