High resolution anatomical mapping confirms the absence of a magnetic sense system in the rostral upper beak of pigeons.
The cells that are responsible for detecting magnetic fields in animals remain undiscovered. Previous studies have proposed that pigeons employ a magnetic sense system that consists of six bilateral patches of magnetite containing dendrites located in the rostral subepidermis of the upper beak. We have challenged this hypothesis arguing that clusters of iron-rich cells in this region are macrophages, not magnetosensitive neurons. Here we present additional data in support of this conclusion. We have undertaken high resolution anatomical mapping of iron-rich cells in the rostral upper beak of pigeons, excluding the possibility that a conserved six-loci magnetic sense system exists. In addition we have extended our immunohistochemical studies to a second cohort of pigeons, confirming that iron rich cells in the upper beak are positive for MHCII and CD44, which are expressed by macrophages. We argue that it is important to critically assess conclusions that have been made in the past, while keeping an open mind as the search for the magnetoreceptor continues.
Centre for Neural Circuits and Behaviour; University of Oxford; Oxford, UK.
Christoph Daniel
CD
Treiber
Marion
M
Salzer
Martin
M
Breuss
Lyubov
L
Ushakova
Mattias
M
Lauwers
Nathaniel
N
Edelman
David Anthony
DA
Keays
anatomical mapping; magnetite; magnetoreception; navigation; pigeons