We report three patients with selective topographic disorientation due to small, focal hemorrhages extending from the right retrosplenial region to the medial parietal lobe. All three could discriminate and identify familiar buildings and landscapes, but had great difficulty remembering spatial positional relationships between two distant locations (i.e., the direction from one location to another) in familiar areas. These symptoms were different than the perception and memory deficits for buildings and landscapes caused by the medial temporo-occipital lesion. These findings suggest that the directional orientation between two locations within a familiar area ("sense of direction") is closely associated with the right retrosplenial region and the medial parietal lobe in humans.

Objective:To clarify the genetic, clinicopathologic, and neuroimaging characteristics of patients with hereditary diffuse leukoencephalopathy with spheroids (HDLS) with the colony stimulating factor 1 receptor (CSF-1R) mutation.Methods:We performed molecular genetic analysis of CSF-1R in patients with HDLS. Detailed clinical and neuroimaging findings were retrospectively investigated. Five patients were examined neuropathologically.Results:We found 6 different CSF-1R mutations in 7 index patients from unrelated Japanese families. The CSF-1R mutations included 3 novel mutations and 1 known missense mutation at evolutionarily conserved amino acids, and 1 novel splice-site mutation. We identified a novel frameshift mutation. Reverse transcription PCR analysis revealed that the frameshift mutation causes nonsense-mediated mRNA decay by generating a premature stop codon, suggesting that haploinsufficiency of CSF-1R is sufficient to cause HDLS. Western blot analysis revealed that the expression level of CSF-1R in the brain from the patients was lower than from control subjects. The characteristic MRI findings were the involvement of the white matter and thinning of the corpus callosum with signal alteration, and sequential analysis revealed that the white matter lesions and cerebral atrophy relentlessly progressed with disease duration. Spotty calcifications in the white matter were frequently observed by CT. Neuropathologic analysis revealed that microglia in the brains of the patients demonstrated distinct morphology and distribution.Conclusions:These findings suggest that patients with HDLS, irrespective of mutation type in CSF-1R, show characteristic clinical and neuroimaging features, and that perturbation of CSF-1R signaling by haploinsufficiency may play a role in microglial dysfunction leading to the pathogenesis of HDLS.

There is contradictory evidence regarding whether the impairments of the recognition of emotional facial expressions in Parkinson's disease are specific to certain emotions such as disgust and fear. Generally, neurological case reports on emotion-specific impairments have been suspected of being confounded with the factor of task difficulty. Using a refined assessment method in which the difficulty factors were controlled by means of mixed facial expressions and item response theory, we attempted to clarify whether Parkinson's disease disproportionately impaired the recognition of specific emotions. We studied 14 patients with Parkinson's disease and 39 healthy controls who were matched in terms of gender, age, years of education and intelligence quotient. Whereas the refined method revealed that the patients with Parkinson's disease displayed significantly lower scores in disgust recognition alone, conventional methods failed to detect this impairment. In addition, control measures including face recognition abilities did not statistically explain the impairment observed in the patients. The results indicate that Parkinson's disease can indeed selectively impair the recognition of facial expressions of disgust; this provides concrete evidence for emotion-specific impairments that sufficiently withstands criticisms regarding the difficulty artefacts. Furthermore, the results support the proposed role of the basal ganglia-insula system in disgust recognition. This study effectively demonstrates the benefits of refining neuropsychological assessment by taking advantage of the modern psychometric theory.

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Recent studies suggest that social recognition processes are affected by Parkinson's disease (PD). However, whether PD patients exhibit behavioral changes is still controversial. The purpose of the present study was to examine the decision making of PD patients performing the Iowa Gambling Task (IGT). We recruited a large number of early, nondemented PD patients for the IGT. We also recorded the skin conductance responses (SCRs) during the task as a measure of emotional arousal. Compared with the normal control (NC) subjects, PD patients selected more disadvantageous decks in the IGT, and their SCRs were lower than those of NC subjects before making decisions and after receiving reward or punishment. The tendency toward risky choices was not correlated with age, education, global cognitive function, or the severity of the disease. These results confirmed that the decision making of PD patients was affected by the disease, rather than by other cognitive functions; moreover, such behavior was related to lower emotional responses. Behavioral and SCR patterns of PD patients were similar to those of amygdala-damaged patients. The response bias toward risky choices in PD may be explained by the dysfunction of the amygdala, which is known to be involved in risk evaluation.

It remains controversial whether the left inferior frontal gyrus subserves syntactic processing or short-term memory demands. Here we devised a novel picture-sentence matching task involving Japanese sentences with different structures to clearly contrast syntactic reanalysis processes. Using event-related functional magnetic resonance imaging (fMRI), activations under three main conditions were directly compared: a canonical/subject-initial active sentence (AS), a noncanonical/subject-initial passive sentence (PS), and a noncanonical/object-initial scrambled sentence (SS). We found that activation in the dorsal region of the left inferior frontal gyrus (dF3t) was enhanced more by the noncanonical processing under the PS and SS conditions than by the canonical processing under the AS condition, and this enhancement was independent of domain-general factors, such as general memory demands and task difficulty. Moreover, the left posterior superior/middle temporal gyrus (pSTG/ MTG) showed more enhanced responses to object-initial sentences under the SS condition than to subject-initial sentences under the AS and PS conditions, which were not significantly affected by task difficulty. Furthermore, activation in the left lateral premotor cortex (LPMC) increased under the AS, PS, and SS conditions, in that order. It is possible that task difficulty affects the left LPMC, but the three distinct activations patterns suggest that these frontal and temporal regions work in concert to process syntactic structures, with their respective contributions dynamically regulated by linguistic requirements. Hum Brain Mapp 29: [1015][1016][1017][1018][1019][1020][1021][1022][1023][1024][1025][1026][1027] 2008. V V C 2007 Wiley-Liss, Inc.