White matter microstructure alterations in bipolar disorder.

Genetic, neuropathological and magnetic resonance imaging findings support the presence of diffuse white matter cytoarchitectural disruption in bipolar disorder. In this study, diffusion-weighted imaging (DWI) was applied to study cortical white matter microstructure organisation in 24 patients with DSM-IV bipolar disorder and 35 matched normal controls. DWI images were obtained using a 1.5 Tesla scanner and apparent diffusion coefficient (ADC) values were determined over regions of interest placed, bilaterally, in the frontal, temporal, parietal, and occipital white matter. Significantly increased ADC values were found in bipolar patients with respect to normal controls in the right temporal lobe, left parietal lobe and bilateral occipital lobes. ADC values did not associate significantly with age or with clinical variables (p>0.05). Diffuse cortical white matter alterations on DWI in bipolar disorder denote widespread disruption of white matter integrity and may be due to altered myelination and/or axonal integrity.

Shared impairment in associative learning in schizophrenia and bipolar disorder.

BACKGROUND: Schizophrenia (SCZ) and bipolar disorder (BD) share some cognitive commonalities. However, the role of associative learning, which is a cornerstone of human cognition mainly relying on hippocampus, has been under-investigated. We assessed behavioral performance during associative learning in a group of SCZ, BD and healthy controls (HC). METHODS: Nineteen patients with SCZ (36 ± 8.1 years; 13 males, 6 females; all Caucasians), 14 patients with BD (41 ± 9.6 years; 5 males, 9 females; all Caucasians) and 45 HC (27.7 ± 6.9 years; 18 males, 27 females; all Caucasians) were studied. Learning was assessed using an established object-location paired-associative learning paradigm. Subjects learned associations between nine equi-familiar common objects and locations in a nine-location grid. Performance data were analyzed in a repeated measures analysis of variance with time (repeated) and group as factors. RESULTS: Learning curves (performance = (1-e(-k x time)) fitted to average performance data in the three groups revealed lower learning rates in SCZ and BD (k = 0.17 and k = 0.34) than HC (k = 0.78). Significant effects of group (F = 11.05, p < 0.001) and time (F = 122.06, p < 0.001) on learning performance were observed. CONCLUSIONS: Our study showed that associative learning is impaired in both SCZ and BD, being potentially not affected by medication. Future studies should investigate the neural substrates of learning deficits in SCZ and BD, particularly focusing on hippocampus function and glutamatergic transmission.

Orbitofrontal cortex abnormalities in schizophrenia.

The magnetic resonance imaging studies investigating the volumes of the orbitofrontal cortex in patients suffering from schizophrenia are here presented, trying to elucidate its role for the pathophysiology and for the cognition of the disease.

Increased left parietal volumes relate to delayed language development in autism: a structural mri study.

The neural basis of language and motor deficits in autism is still not completely clear. The aim of this study was to explore the involvement of the parietal lobe in language and motor development in autism, in view of the recognized role of this region in language and imitation functions. Twenty-eight autistic children underwent an extensive clinical assessment and an MRI examination. A significant direct correlation between age at first word and left parietal gray matter volumes was found (r=0.50, p=0.007). Conversely, age at reaching milestones of motor development, such as the ability to sit and to walk unaided, was not significantly associated with parietal size, after correcting for chronological age and for gender. To the best of our knowledge, this is the first structural MRI report demonstrating a role of left parietal gray matter volumes in delayed language development in autistic children representative of the 'real world' autistic population.

Laterality effects in schizophrenia and bipolar disorder.

There are numerous reports in the literature of lateralised structural cerebral abnormalities and alterations of the corpus callosum in the major psychoses. In the light of these findings the purpose of this study was to directly compare hemispheric differences and callosal interhemispheric transmission (IT) in schizophrenia and bipolar disorder. To do that we tested schizophrenic (SCZ), bipolar disorder (BD) patients and controls in a simple manual reaction time (RT) task with lateralised visual stimuli (Poffenberger paradigm) which enables one to test both laterality effects and IT time. We found an overall slowing of responses with the right hand in schizophrenics but not in bipolar patients, who, like controls, showed no hand differences. This selective slowing down of the right hand is likely to be related to abnormalities of intrahemispheric cortico-cortical connections in the left hemisphere. In contrast, IT time was similar in SCZ and BD patients and did not differ with respect to controls. Two are the novel findings of the present study: first both SZC and BD share a normal IT of visuomotor information despite the presence of callosal abnormalities. Second, an impairment of intrahemispheric left hemispheric processing is present only in SCZ patients. This represents a potentially important clue to a further understanding of the pathogenetic differences between the two major psychoses.

Specific linguistic and pragmatic deficits in Italian patients with schizophrenia.

OBJECTIVE: Verbal communication impairments are prominent features of schizophrenia. The grammatical and pragmatic components of expressive and receptive verbal abilities were systematically examined, for the first time, in Italian patients with schizophrenia. Indeed, most of the language literature is composed of studies on English speaking people. METHOD: Elicited narrative production, and syntactic and pragmatic receptive abilities were analyzed in a cohort of 37 patients with schizophrenia and 37 healthy controls. Furthermore, a conversational speech production task was administered to an age- and gender-matched subset of this population. The level of significance was set at p