Nature issued an Expression of Concern regarding a 1999 paper. The article, "En passant neurotrophic action of an intermediate axonal target in the developing mammalian CNS," faces scrutiny. Concerns arose over image irregularities in Figure 5, panels a and b.

The announcement, published online October 21, 1999, highlights unexpectedly similar backgrounds in the figure panels. Authors stated the panels depict the same tissue explant at 24 and 52 hours. They intended to illustrate axonal degeneration. Crucially, the original data is now unavailable, according to the authors.

Nature's editors urge caution in interpreting the paper's results and conclusions. This expression of concern serves as a flag for the scientific community. Readers should carefully consider the potential impact on subsequent research.

The 1999 study explored axonal behavior in the developing mammalian central nervous system. It investigated how intermediate targets influence neuronal growth. Such research is foundational for understanding neural development.

Further investigation is unlikely due to the unavailability of original data. The scientific community will now re-evaluate the paper's findings in light of these concerns. Future research building upon this work may require additional validation.