Patterns of neuropsychological deficits that discriminate schizophrenic individuals from siblings and control subjects

Previous research on persons with schizophrenia and their relatives suggests two independent etiologic factors may combine to produce schizophrenia, and these factors may be indexed respectively by independent neuropsychological tests. Two neurocognitive measures, the Trail Making and Wisconsin Card Sorting (WCST) tests, were administered to 28 schizophrenic subjects, 15 nonschizophrenic siblings, and 35 control subjects by investigators blind to DSM-III-R diagnoses. Results support key predictions of a two-factor model: 1) having poor scores on both tests discriminated schizophrenic individuals from both siblings and control subjects, and 2) poor Trail Making and WCST performance were inversely associated among schizophrenic individuals' non-schizophrenic siblings.

Neurologic signs in patients with paranoid and nonparanoid schizophrenia

Previous research found that both persons with schizophrenia and their unaffected relatives had significantly more neurologic signs than normal controls. As hypothesized, in this study neurologic signs were significantly greater in patients with nonparanoid than paranoid schizophrenia; the difference was greatest for "hard" signs.

Neurological "hard" signs and family history of psychosis in schizophrenia

Previous research found schizophrenics to have significantly more neurological signs than normal controls, even when signs were screened to exclude possible artifacts, and limited to "hard" signs of localizing significance. Schizophrenics with a family history of psychosis also tended to have more neurological signs than those without such a history. The present study examined whether these findings could be confirmed in new samples of schizophrenics and controls, using interview-based DSM-III and DSM-III-R diagnoses. Schizophrenics had significantly more hard signs than controls, and schizophrenics with a family history for psychosis again had more signs than those without this history. When present study data were analyzed alone, as well as when pooled with data from previous research using similar methods, hard signs were significantly greater in both (a) schizophrenics versus controls and (b) schizophrenics with versus without a family history of psychosis, supporting the hypothesis that neurological signs reflect a significant etiologic factor in schizophrenia.

Hard neurologic signs and psychopathology in relatives of schizophrenic patients

Previous research found more hard neurologic signs (i.e., signs that have localizing significance and exclude likely artifacts) in the nonschizophrenic relatives of schizophrenic patients than in control subjects, and in the psychiatrically normal relatives of schizophrenic patients compared with their ill relatives. Using interview-based DSM-III-R diagnoses and standard clinical neurological examinations on new samples, we found a trend to more hard signs in the 52 nonschizophrenic relatives of schizophrenic patients than in 20 control subjects, and significantly more signs in psychiatrically normal relatives than in ill ones. When pooled with previous data, signs were significantly higher in (1) relatives vs. controls and (2) normal vs. ill relatives, suggesting neurologic signs reflect an etiologic factor that often runs in families of schizophrenic patients.

The neuronal architecture of the anteroventral cochlear nucleus of the cat in the region of the cochlear nerve root: horseradish peroxidase labelling of identified cell types

Golgi impregnations of the posterior part of the cat's anteroventral cochlear nucleus have revealed two types of neurons, bushy cells with short bush-like dendrites and stellate cells with long, tapered processes; Nissl stains have revealed globular and multipolar cell bodies with dispersed and clumped ribosomal patterns, respectively. In the present study, we injected horseradish peroxidase into the trapezoid body. Ipsilaterally, retrograde, diffuse labelling of neurons, presumably through damaged fibers, yielded Golgi-like profiles of numerous bushy cells with typical dendrites and with thick axons projecting toward the trapezoid body. Stellate cells were almost never labelled in this way. Anterograde diffuse labelling of thick axons demonstrated calyx endings in the contralateral medial nucleus of the trapezoid body. In the electron-microscope, the perikarya of diffusely-filled bushy neurons were found to have the dispersed ribosomal pattern and the kinds of synaptic endings typical of globular cells, including large profiles of end-bulbs from cochlear nerve axons. After injections restricted to the medial trapezoid nucleus, granularly-labelled cells in the cochlear nucleus were almost completely confined to the contralateral side; Nissl counterstaining showed them to be globular cells in the posterior part of the anteroventral cochlear nucleus. After larger injections, involving surrounding regions of the superior olivary complex, granular labelling occurred throughout the ventral cochlear nucleus on both sides. There is also evidence that stellate cells in Golgi impregnations correspond to multipolar cell bodies in Nissl stains. We conclude that bushy cells typically correspond to globular cells, which receive end-bulbs from the cochlea and send thick axons to the contralateral medial trapezoid nucleus, where they form calyces on principal cells. Principal cells, in turn, are known to project to the lateral superior olive and to one of the nuclei of origin of the crossed olivo-cochlear bundle, which feeds back to the cochlea. In this circuit, correlations between synaptic patterns and particular physiological signal transfer characteristics can be suggested. These could be related to binaural intensity interactions in the lateral superior olive and to a regulatory loop involving the olivo-cochlear bundles.