Morphometric dendritic field analysis of pyramidal neurons in the human prefrontal cortex: relation to section thickness.

The 3-dimensional (3D) basal dendritic branching patterns of the layers IIIc and V pyramidal neurons in the human prefrontal cortex were morphometrically analyzed using Golgi-Cox stained single sections without reconstruction. Since the dendritic field extends beyond the section, the section thickness affected its 3D measures, such as total dendritic length per neuron. An exploratory analysis to assess the cutting effect in relation to section thickness was performed by examine the graphic display of the following dendritic measures per section thickness class of 10 microns, within a total range of 101-210 microns: (1) percentage cut dendritic segments, (2) individual terminal segment length, (3) radial distance from the terminal tips, and (4) total dendritic length per neuron. Additionally, 1-way analysis of variance (ANOVA) was applied with section thickness as main factor. The graphic displays did not show a trend towards increasing dendritic lengths and distances with increasing section thickness. In general the ANOVA showed no statistically significant effect of section thickness, with the exception of one thickness class (layer IIIc: 151-160 microns). This leads to the conclusion that the thickness range has to be larger to detect a cutting effect related to section thickness.

Postnatal maturation of layer V pyramidal neurons in the human prefrontal cortex. A quantitative Golgi analysis.

The pattern of dendritic development of layer V pyramidal neurons in the human prefrontal cortex was studied quantitatively. The main objective was to determine how dendritic growth and differentiation continued postnatally. In order to do this, we analyzed the three-dimensional branching pattern of the basal dendritic field of Golgi-Cox impregnated neurons. The subjects ranged in age from 7.5 months after birth up to 27 years. The results revealed a maturational time-course with a rapid dendritic growth phase during the first postnatal year. The dendritic length and radial extension of the basal field increased. The growth continued, at a reduced rate, up to around 5 years of age by a lengthening of the terminal segments and a slight increase in soma size. The morphological maturation of the layer V pyramidal neurons was completed between one and five years. After this age the dendritic values appeared to level off and reach a stable level that lasted up to at least 27 years. This paper gives no indications for overgrowth or regressive events of the layer V basal dendritic trees during development.

Postnatal maturation of the layer III pyramidal neurons in the human prefrontal cortex: a quantitative Golgi analysis.

In this study we examined the morphological maturation of the basal dendritic field of layer III pyramidal neurons located in the human dorsolateral prefrontal cortex in subjects ranging from 7.5 months after birth up to 27 years. The sections were stained with the Golgi-Cox method and the three-dimensional branching pattern was measured with a semi-automatic dendrite measuring system. Results show a rapid growth phase of the dendritic field from 7.5 months after birth up to one year. A marked increase in total dendritic length is observed, for which elongation of the terminal segments, longer intermediate segments and an increase in number of segments is an explanation. The dendritic length appears to have stabilized after one year, leading us to conclude that the postnatal morphological maturation of the layer III pyramidals does not continue well into childhood, but is completed at a much younger age. Additionally we analyzed the effect of varying section thickness on dendritic parameters and found no tendency for higher dendritic values with increasing section thickness for the range of thickness values of the histological sections used.

Non-invasive assessment of autonomic nervous function in Gilles de la Tourette syndrome.

Autonomic nervous function was investigated in 18 Gilles de la Tourette (GTS) patients and in 23 controls, who matched the patients in age, sex, baseline blood pressure and baseline heart rate. Four heart rate tests were used (variation at rest, during deep breathing, following standing up and during a Valsalva manoeuvre), and two blood pressure tests (standing up and sustained handgrip). The only significant difference between the groups was found in the Valsalva test. This was due to the initial heart rate increase which was higher in the GTS group; the subsequent decrease did not differ between the groups. Increased sympathetic activity is a possible explanation for this finding, but no additional evidence in its favour was found. No signs of autonomic failure were found.

Autonomic nervous function in progressive supranuclear palsy.

Autonomic nervous function was assessed in 11 patients with progressive supranuclear palsy, 26 patients with Parkinson's disease, matched for age, medications, disease severity, and disease duration, and 19 age-matched controls. Results of both parasympathetic (heart rate response to deep breathing and Valsalva maneuver) and sympathetic (blood pressure decrease on standing and increase on sustained handgrip) tests were abnormal in both patient groups. Abnormalities in the group of patients with progressive supranuclear palsy were similar to those in the group with Parkinson's disease but were more pronounced. Autonomic dysfunction may have to be considered a feature of progressive supranuclear palsy.

Long-term EEG monitoring in the early premature: developmental and chronobiological aspects.

Long-term cassette EEG monitoring in the neonatal intensive care unit has established prognostic criteria regarding the developmental outcome by quantifying seizure activity. The clinical significance of the organization of continuous and discontinuous EEG patterns in the early premature is still an open question. This report presents quantified EEG data from repeated 24 h records during the first week of life in premature infants (conceptional age less than 32 weeks) with and without ultrasound evidence of intracerebral hemorrhage. The repartition and evolution of EEG background activity is not a reliable parameter regarding pathology. The continuity index is rather a maturational variable and its ultradian fluctuation is an early expression of the "basic rest activity cycle" (BRAC) rhythm.

Autonomic nervous system tests depend on resting heart rate and blood pressure.

In order to study the effects of baseline blood pressure and heart frequency on autonomic function tests, 75 normal subjects (aged 8-96 years) were investigated. Heart rate variability was studied at rest, during deep breathing, following standing up and during a Valsalva manoeuvre. Blood pressure changes were recorded during standing up and during sustained handgrip. Responses were described as ratios and as differences to study the efficacy of both methods. Multiple regression analysis showed that significant relationships with the resting heart rate existed for ratios but not for differences. The blood pressure rise in the sustained handgrip test showed a significant relationship with resting blood pressure regardless of the description method. As expected, relationships with age existed for all four heart rate tests regardless of the description method. The blood pressure responses were not significantly related to age. We advise that heart rate test results should be presented as differences, as this avoids the need for correction for the resting heart rate. Correction for the resting blood pressure improves the accuracy of the standing up blood pressure test. Correction for age remains necessary for heart rate tests but not for blood pressure tests.