APPLICATION OF STEREOLOGY AND MORPHO:METRY ON SYNAPSES AND NEURONS IN THE HIPPOCAMPUS OF AGEING RATS APPLICATION OF STEREOLOGY AND MORPHOMETRY ON SYNAPSES AND NEURONS IN THE IDPPOCAMPUS OF AGEING RATS an illustration of problems and solutions

2D reconstruction and quantification of synapse orthogonal projections (shado\VS) are proposed as apractical approach to obtain information about differences in their actual configuration. Thequantification of the shadows implies estimation of size parameters (area and perimeter) and shapefunctions (i.e. second order moment invariants independent of location and size). The method wasapplied to twO synapse types. non-perforated and perforated synapses,. in the hippocampal CA3 area of3-months-old rats.Significant differences in size and shape between non-perforated and perforated synapses weredemonstrated. The perforated synapses are larger and the invaginations in their boundary aresignificantly more pronounced. This may reflect an increased efficacy of the perforated synapses ascompared with the non-perforated ones. The difference in invagination of the boundary of the twosynapse types could not be detected. from visual inspection of the reconstruCted orthogonal projections. Key-wordsgeometric moments moment invariants (non-)perforated synapses orthogonal projectiOns