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This paper discusses the concepts of fractal geometry in a cellular biological context. It defines the concept of the fractal dimension. D, as a measure of complexity and illustrates the two different general ways of quantitatively measuring D by length-related and mass-related methods. Then, these several Ds are compared and contrasted. A goal of the paper(More)
Pyramidal neurons in the mammalian cerebral cortex can be described by a fractal dimension (Mandelbrot, 1982), which is an objective, quantitative measure of the complexity of their soma/dendritic borders. In the cat, the fractal dimensions of lamina V cells, which include pyramidal tract neurons (PTN), indicate that these cells are more complex than other(More)
Methods of digital image analysis have been adapted to measure the fractal dimension of cellular profiles. The fractal dimension is suggested as a useful measure of the complexity of a contour. Three methods produce similar results when applied to constructed, near-ideal fractal figures. Comparison of the measurements for a variety of image types indicates(More)
Details of the morphology of light microscope images of horseradish peroxidase labeled mammalian neurons in cell culture were investigated. A modified Marr-Hildreth edge-detecting algorithm was used in an image processor to obtain a continuous border of the labeled neurons. The interior of the border was filled to obtain isolated binary silhouettes of the(More)
Sympathetic nerve stimulation indirectly regulates pancreatic endocrine and exocrine secretion, in part, through actions on the cholinergic parasympathetic innervation of the secretory tissues. Earlier work identified noradrenergic nerves in pancreatic ganglia and demonstrated the effects of exogenous norepinephrine (NE) on synaptic transmission but no(More)
Astrocytes from area 11 of the human neocortex were Golgi-impregnated. The material was taken from four human subjects, (1) a neonate without obvious CNS damage, (2) a middle-aged adult serving as control, (3) an aged individual without apparent mental disturbances, and (4) an aged patient with dementia. Camera-lucida drawings of 7 to 26 astrocytic cells(More)
On each trial, after three squares of different sizes (inducing display) were sequentially presented at central fixation, a target square was briefly lateralized to the right or left hemisphere (RH or LH) of 24 normal right-handed males. Subjects determined whether or not the target differed in size from the third inducing square. Half of the targets that(More)
Pharmacological studies using an in vitro model system were carried out to determine if naloxone, an opiate receptor antagonist, could have effects on neuronal membranes which were unrelated to its action as an opiate receptor antagonist. Intracellular recordings were made from cultured mammalian spinal cord neurons. Putative amino acid neurotransmitters(More)