Increased flexibility and selectivity in spatial learning of transgenic mice ectopically expressing the neural cell adhesion molecule L1 in astrocytes.
The expression of the neural cell adhesion molecule L1 is altered by neuronal activity and promotes neurite outgrowth in vitro. To study the effects of L1 on learning and synaptic plasticity, transgenic mice have been created which express L1 ectopically in glial fibrillary acidic protein (GFAP) expressing astrocytes. Ninety mice, including GFAP-L1-transgenic mice from two genetic backgrounds and their littermates, were tested for swimming navigation learning in the Morris water maze according to a standardized protocol. While learning the position of an invisible target platform and also relearning its position after relocation, GFAP-L1-transgenic mice spent a greater fraction of their swim time in the target quadrant. Moreover, they showed a more rapid improvement of escape performance during the first day of training. Factor analysis revealed that this difference in swimming pattern could not be explained by non-cognitive factors. Factor analysis also revealed that, during a probe trial, the GFAP-L1-transgenic mice spent comparatively less time in the old target quadrant than predicted by the increased searching they had shown during acquisition learning. Hence, ectopic expression of L1 by astrocytes in mice appears to be linked to a factor which increases behavioural flexibility and selectivity while learning and relearning, but concomitantly may lead to a relative reduction of spatial retention.
Wolfer
D P
DP
Department of Anatomy, University of Zürich, Switzerland. dpwolfer@anatomie.unizh.ch
Mohajeri
H M
HM
Lipp
H P
HP
Schachner
M
M
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D001522:Behavior, Animal / Q000502:physiology; D005163:Factor Analysis, Statistical; D005838:Genotype; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis / Q000235:genetics; D007858:Learning / Q000502:physiology*; D039841:Leukocyte L1 Antigen Complex; D018782:Maze Learning / Q000502:physiology; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D019006:Neural Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D013028:Space Perception / Q000502:physiology*
D005904:Glial Fibrillary Acidic Protein; D039841:Leukocyte L1 Antigen Complex; D008562:Membrane Glycoproteins; D019006:Neural Cell Adhesion Molecules