A technique for estimating total spine numbers on golgi‐impregnated dendrites

Abstract

The functional significance of dendritic spines and their morphological sensitivity to a wide spectrum of experimental manipulations and pathological states have led to a number of studies in which counts of dendritic spine number have been carried out. These studies have, for the most part, involved the enumeration of only those spines which protrude from the opaque shafts of Golgi-impregnated dendrites into the clear zones flanking the dendrite. Such counts, limited to only those spines which are visible, underrepresent the true total number of spines borne by the dendrites. The magnitude of underrepresentation correlates positively with dendritic shaft diameter and negatively with spine length. This seriously restricts the usefulness of comparisons of spine density between dendrites, or even between segments of the same dendrite. In the present report, a geometrically based method is presented whereby total dendritic spine numbers can be estimated with reasonable accuracy, taking into account factors such as dendrite diameter and spine length. The technique entails the following principal steps: a determination, for a given length of dendrite over which spines are to be enumerated, of the volume of the flanking zones in which spines are visible and can be counted; a determination of the volume of the entire zone which encircles the dendritic shaft and which contains all spines, both visible and not visible; and a proportional extrapolation from the number of visible spines to obtain an estimate of the true total spine number. Tests of the predictive accuracy of the technique using dendrites of known total spine number suggest that estimates which deviate from true total spine numbers by less than 10% can be achieved.

Neonatal Phencyclidine Treatment in Mice Induces Behavioral, Histological and Neurochemical Abnormalities in Adulthood

“…Dendritic spines were counted manually using the point picker function of the partial analysis. As has been described by others, 18) this represents an underestimation of the total number of spines as those that extended downward or upward in the plane of the section were obscured by the shaft of the dendrite and therefore were not counted.…”

“…Spontaneous Locomotor Activity PCP-treated mice were subjected to the behavioral experiment at postnatal weeks [15][16][17][18][19]. The animals were housed individually in plastic cages (W-D-H: 215ϫ320ϫ140 mm) and acclimatized for 3 d before the measurement of spontaneous locomotor activity.…”

Amphetamine Sensitization Alters Dendritic Morphology in Prefrontal Cortical Pyramidal Neurons in the Non-Human Primate

“…Spines extending perpendicularly outward from the parent dendritic process were drawn. As has been described by others (Feldman and Peters, 1979), this represents an underestimation of the total number of spines as those that extend downward or upward in the plane of the section were obscured by the shaft of the dendrite and therefore were not counted. Cases were excluded from the analysis of spine density of specific processes if five well-impregnated and unobscured dendrites were not found (two control cases for apical trunk spine density in layer II/IIIs, one AMPH-sensitized monkey for apical trunk spine density in layer V/VI, and one AMPH-sensitized monkey for apical branch spine density in layer V/VI).…”

A novel computational approach for automatic dendrite spines detection in two-photon laser scan microscopy

“…However, the analysis of neuron images generated by either modality has remained largely manual. Even with computer assistance, such analysis is still extremely time-consuming, and subject to user bias, i.e., results cannot be easily confirmed by other investigators [14]- [16]. Thus, automation is in great need for dendritic spine analysis.…”