Publications by authors named "A E Hallanger"

The idea of working with a near-critical phase-separated liquid mixture whereby the surface tension becomes weak, has recently made the field of laser manipulation of liquid interfaces a much more convenient tool in practice. The deformation of interfaces may become as large as several tenths of micrometers, even with the use of conventional laser power. This circumstance necessitates the use of nonlinear geometrical theory for the description of surface deformations.

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The principal relay nuclei of the thalamus receive their cholinergic innervation from two midbrain cholinergic groups: the pedunculopontine tegmental nucleus and the laterodorsal tegmental nucleus. The different thalamic nuclei exhibit populations of cholinergic axons which vary in density and morphology when examined at the light microscopic level. However, the ultrastructure of the cholinergic terminals in different thalamic nuclei has not been described.

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The thalamic reticular nucleus has been shown to receive cholinergic innervation from both the nucleus basalis of Meynert in the forebrain and the pedunculopontine and laterodorsal tegmental nuclei in the brainstem (Steriade et al.: Brain Res. 408:372-376, '87; Levey et al.

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Previous studies have suggested that the pedunculopontine tegmental nucleus (PPTn) is reciprocally connected with extrapyramidal motor system nuclei (EPMS) whereas other studies have implicated the PPTn in behavioral state control phenomena such as sleep-wakefulness cycles. Many of these studies define the nonprimate PPTn as an area of mesopontine tegmentum which is labeled from injections of anterograde tracers into the basal ganglia. Recently, we have defined the rat PPTn as a large-celled, cholinergic nucleus.

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Ascending projections from the pedunculopontine tegmental nucleus (PPT) and the surrounding mesopontine tegmentum to the forebrain in the rat are here examined by using both retrograde and anterograde tracing techniques combined with choline acetyltransferase (ChAT) immunohistochemistry. The anterogradely transported lectin Phaseolus vulgaris-leukoagglutinin (PHA-L) was iontophoretically injected into the PPT in 12 rats. Anterogradely labelled fibers and varicosities were observed in the thalamic nuclei, confirming the findings of our previous retrograde studies (Hallanger et al: J.

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