E Martínez-Moreno | PubMed Health

PubMed1999

Gold chloride technique to study articular innervation. A protocol validated through computer-assisted colorimetry.

We studied variations in gold chloride techniques to elicit neural elements within articular samples, after "in toto" staining. These techniques attempt the differentiation of neural and vascular structures. Major changes in differential staining were observed when the gold chloride concentration was empirically modified. After the rest of the technique was standardized, we selected three gold chloride solutions to perform quantitative color experiments: 1%, 0.75%, and 0.5%. Significant sections of the same thickness were acquired with a digital camera to perform computer-assisted colorimetry. Color was measured through RGB (red-green-blue) channels in vessels, nerves, and background connective tissue as an internal control. By means of multivariate regression analysis, we compared differences in color measurements after 1%, 0.75% and 0.5% gold chloride preparation. Statistically significant coefficients confirmed that red color signals in vessels after the 0.75% and the 0.5% solution were both less intense than after the 1% preparation. Green and blue signals in vessels were also significantly less intense after the 0.5% protocol than after using the 1% solution. Red color signals in nerves between the 1% and the 0.75% preparation protocols were more intense and not significantly different, while the 0.5% preparation produced significantly less intense red signals in nerves. Non-significant differences were observed in green or blue signals from nerves after any protocol. We concluded that the 0.75% gold chloride solution protocol produced more intense red signals in nerves and less intense red signals in vessels. This was the most discriminant protocol in our series, based on color signals.

Adolescent↗

PubMed1987

General plan of the thalamic projections to the prefrontal cortex in the cat.

This study elucidates the general pattern of the thalamocortical neurons which project to the prefrontal cortex (PfC) in the cat, on the basis of the findings obtained using different retrograde labeling techniques in a large number of animals. The injections of the retrograde tracers covered the whole extent of the PfC, and did not invade gray or white matter outside the intended targets. The labeled neurons formed a vertical paramedian band throughout the rostrocaudal extent of the thalamus. This band was densest at the mediodorsal and ventromedial nuclei regions, encroached upon neurons located more medially and laterally, and largely spared the intralaminar nuclei. There were overlaps between neuron populations projecting to different subdivisions of the PfC, or to the PfC and sectors of the motor, insular, limbic and anterior ectosylvian sulcus cortices. However, these projections to separate cortical subdivisions apparently arise from different neuron clusters, with little collateralization of the axons arising from a single thalamocortical neuron. Only the neurons of the ventromedial nucleus, seem to possess somewhat more widespread terminal axons in the cortex.

Amidines↗