Visual pseudohallucinations: psychotherapy case study of a long-standing perceptual disorder.

The case of a woman with severe neurosis, seen in once weekly psychotherapy over a period of 3 years, illustrates many of the characteristics of pseudohallucinations: their relation to personality, to sensory deprivation and isolation, and to developmental factors. It also suggests that there may be more than one type of pseudohallucinatory experience.

Ultrastructural localization of somatostatin-like immunoreactivity in the rat dentate gyrus.

Neurons containing somatostatin (SOM) are enriched in the dentate gyrus. We sought to establish the ultrastructural localization of this peptide in the dentate gyrus of the rat brain with a double-bridged peroxidase-antiperoxidase (PAP) method localizing antisera directed against somatostatin (SOM)-28 and SOM-28. Initial light microscopic observations confirmed that the majority of perikarya and thick varicose processes with intense SOM-like immunoreactivity (SOM-LI) were observed in the hilus. Fine varicose processes with SOM-LI were found throughout all layers of the dentate gyrus but were most intense in the outer third of the molecular layer (ML), where an occasional perikaryon with SOM-LI was seen. By electron microscopy, SOM-LI was found in neuronal perikarya, dendrites, axons, and axon terminals. Two types of SOM-containing perikarya were observed. The first type was small (6-10 microns), round or avoid, and had a labeled cytoplasma with abundant Golgi complexes and a dense accumulation of PAP-reaction product. The second type of perikarya was larger (11-16 microns) and had a more abundant cytoplasm than the first type, but the Golgi complexes did not appear labeled. Most (96% of 374) of the synapses on the SOM-labeled perikarya and dendrites were from terminals without SOM-LI which formed nearly equal proportions of asymmetric and symmetric junctions. The remainder of the presynaptic terminals contained SOM-LI and made primarily symmetric synapses. Synaptic junctions from both unlabeled and labeled terminals were primarily on the shafts of the small (0.5-1.5 microns) SOM-immunoreactive dendrites. The terminals with SOM-LI (0.25-1.3 microns) contained many small, clear vesicles and from zero to four large dense-core vesicles. Terminals with SOM-LI were associated 1) with one unlabeled perikaryon or dendrite (49% of 215 in the hilus; 76% of 326 in the ML); 2) with two unlabeled perikarya or dendrites simultaneously (5% hilus; 4% ML); and 3) with one SOM-containing perikaryon or dendrite (6% hilus; 3% ML). In all three types of associations, synaptic contacts on perikarya were few while the majority were with small (distal) dendrites. Moreover, most of the terminals with SOM-LI formed symmetric junctions or lacked membrane specializations but were without any apparent glial intervention in the plane of section analyzed. The remaining SOM-labeled terminals (40% hilus; 17% ML) were without any apparent synaptic relations. However, a few of these terminals were in direct apposition to other terminals, some of which were also SOM-immunoreactive.(ABSTRACT TRUNCATED AT 400 WORDS)

GABAergic neurons in the rat hippocampal formation: ultrastructure and synaptic relationships with catecholaminergic terminals.

Numerous studies indicate that gamma-aminobutyric acid (GABA) can either hyperpolarize or depolarize hippocampal pyramidal and granule cells. While the inhibitory action of GABA may occur directly on these cells, the excitatory action may be mediated by interactions of GABAergic neurons with each other or with catecholaminergic afferents. We sought to examine the cellular basis for these interactions and their relative frequency. Thus, the ultrastructural morphology of GABAergic neurons and their relation to terminals exhibiting immunoreactivity for the catecholamine-synthesizing enzyme tyrosine hydroxylase (TH) were examined in the rat hippocampal formation using combined immunoautoradiographic and peroxidase-antiperoxidase labeling methods. By light microscopy, GABAergic perikarya and processes codistributed most noticeably with TH-containing processes in the hilus of the dentate gyrus (DG) and in strata lucidum, radiatum, and lacunosum-moleculare of the CA3 region of the hippocampus. Thus, these regions were examined further by electron microscopy. In the ultrastructural analysis, GABA-like immunoreactivity (GABA-LI) was detected in neuronal perikarya, dendrites, axons, and axon terminals. The GABA-containing perikarya were large, ovoid (20-40 microns in diameter), and contained abundant cytoplasm and an indented nucleus with one nucleolus. Synaptic junctions on the perikarya and dendrites with GABA-LI were both symmetric and asymmetric. Approximately equal numbers of TH-labeled terminals (19% of 133 in DG; 39% of 26 in CA3) and GABA-containing terminals (19% DG, 15% CA3) formed synapses with GABA-labeled perikarya. The remainder of the presynaptic terminals (62% DG, 46% CA3) were unlabeled, i.e., contained unidentified transmitters. Terminals with GABA-LI (0.5-1.6 microns) contained numerous small clear vesicles and from 0 to 2 large dense-core vesicles. The types of associations formed by terminals with GABA-LI were remarkably similar in the DG and hippocampus proper despite differences in intrinsic cell type and function. Terminals with GABA-LI formed associations with unlabeled perikarya and dendrites (24% of 151 in DG, 25% of 75 in CA3) and synapses with GABA-containing perikarya and dendrites (18% DG, 5% CA3). Additionally, GABAergic terminals converged upon the same perikarya or dendrite as a TH-containing terminal (15% DG, 21% CA3) and were in direct apposition to TH-labeled terminals (19% DG, 20% CA3). The remaining GABAergic terminals (24% DG, 28% CA3) were without any apparent synaptic relations. In both the DG and CA3, the junctions formed by GABAergic terminals were symmetric. Terminals showing colocalization of GABA-LI and TH-I were also detected although rarely.(ABSTRACT TRUNCATED AT 400 WORDS)

Ultrastructural localization of tyrosine hydroxylase-like immunoreactivity in the rat hippocampal formation.

The light and electron microscopic localization of antigenic sites for a polyclonal antiserum directed against the catecholamine synthesizing enzyme, tyrosine hydroxylase (TH), was examined in the hippocampal formation of the rat brain with a double-bridged peroxidase-antiperoxidase method. By light microscopy, the majority of varicose processes with intense TH-like immunoreactivity (LI) were contained in the hilus of the dentate gyrus (DG) and strata radiatum and lacunosum-moleculare of the CA3 region of the hippocampus. Only a few immunoreactive fibers were observed in the molecular and granule cell layers of the DG, in strata oriens and pyramidale of CA3, and in all layers of CA1. Electron microscopy confirmed that these labeled processes were primarily axons and axon terminals. Terminals with TH-LI were 0.4-1.1 micron in diameter and contained many small clear vesicles and from 0 to 3 larger dense-core vesicles. The number and types of associations formed by terminals with TH-LI were remarkably similar in the DG and hippocampus proper despite known differences in intrinsic cells and function. In both regions, the majority of terminals with TH-LI formed junctions on small (distal dendrites (52% of 112 in the DG; 67% of 116 in CA3) and dendritic spines (30% in the DG; 18% in CA3) that were both asymmetric and symmetric. In the DG, axosomatic junctions (2% of 112) were symmetric and occurred exclusively on the perikarya of granule cells, whereas junctions on large (proximal) dendrites were more numerous (16%), exhibited symmetric as well as asymmetric membrane specializations, and were of both granule (molecular layer) and nongranule (hilus) cell origin. In CA3, synaptic contacts on perikarya (5% of 116) and large (proximal) dendrites (10%) of both pyramidal cell and nonpyramidal cell origin were few and all symmetric. The distribution and types of synaptic associations formed by terminals with TH-LI in the CA1 region paralleled that seen in the CA3 region. In both the dentate and hippocampus proper, 10% of the terminals with TH-LI were observed closely apposed to unlabeled terminals that formed asymmetric synapses with dendrites and dendritic spines. In rare instances, TH-immunoreactive terminals were found in close association with the basement membrane of blood vessels, astrocytic processes, or with other unlabeled terminals not forming recognizable junctions. In addition TH-LI was occasionally detected within the cytoplasm of a minority of astrocytes.(ABSTRACT TRUNCATED AT 400 WORDS)