Atsutaka Hashimoto

Efferent connections of the rostral portion of medial agranular cortex in rats.

This study of the rostral part of medial agranular cortex (AGm) was undertaken with two principal aims in mind. First, to delineate the efferent connections of AGm and compare these with the pattern of afferents defined by us in a previous study. Second, to provide a firmer basis for anatomical and functional comparisons with cortical regions in monkeys. Autoradiographic, horseradish peroxidase, and fiber degeneration techniques were used. Rostral AGm has a variety of corticocortical connections--with lateral agranular motor cortex (AGl); visual, auditory, and somatic sensory regions; and limbic/paralimbic areas including orbital, insular, perirhinal, entorhinal, retrosplenial and presubicular fields. The projections to orbital, perirhinal and entorhinal cortices are bilateral. Thalamic projections of rostral AGm are concentrated in the ventral lateral, central lateral, paracentral, mediodorsal and ventromedial nuclei. Moderate terminal fields are consistently seen in the reticular, anteromedial, central medial, gelatinosus, parafascicular, and posterior nuclei. More caudal projections reach the central gray, superior colliculus and pontine gray. The efferents of the adjacent AGl were also examined. Although many of these overlapped those of rostral AGm, there were no efferents to visual or auditory cortex and limbic/paralimbic projections were reduced. Thalamic projections were more focused in the ventral lateral and posterior nuclei and there were no terminal fields in the central gray or superior colliculus. Based on its afferent and efferent connections, role in contralateral neglect, and the results of microstimulation studies, rostral AGm can be viewed as a multimodal association area with strong ties to the motor system. On these structural and functional grounds, rostral AGm bears certain striking resemblances to the frontal eye field, supplementary motor, and arcuate premotor areas of monkey cortex.

Afferent connections of medial precentral cortex in the rat

The principal sources of input to rat medial precentral cortex (PCm), as revealed by iontophoretically applied horseradish peroxidase, are: the ventral lateral, mediodorsal, central lateral and ventromedial thalamic nuclei; contralateral PCm; ipsilateral cortical areas related to vision, somatic sensation and audition; retrosplenial and ventrolateral orbital cortex. These results are compared to findings in monkeys and discussed in relation to the phenomenon of polymodal neglect of hemispace.

Apomorphine has a therapeutic effect on neglect produced by unilateral dorsomedial prefrontal cortex lesions in rats

Neglect is a disorder in which the response to stimulation is diminished or absent on the side of the body contralateral to the lesion in the absence of an elemental sensory or motor defect. Most cases of neglect in humans are induced by cortical damage, but there have been no investigations of the pharmacologic basis of neglect induced by cortical damage. We examined the role of the dopamine system in polymodal neglect caused by a unilateral lesion of the medial precentral prefrontal cortex of the rat. A dose-response examination of the effect of apomorphine on neglect revealed that apomorphine, at 0.5 mg/kg, the highest dose examined, significantly improved the orientation scores of subjects in all modalities tested and significantly decreased the total number of allesthetic responses. The therapeutic effect of apomorphine was mediated by dopamine receptors as the therapeutic effect of apomorphine was blocked by prior administration of spiroperidol. These results demonstrate the important role of disruption of dopamine mechanisms in neglect induced by a lesion of medial precentral cortex.

A Case Report of Myasthenia Gravis Associated with Hashimoto′s Thyroiditis

Abstract: An unusual case of myasthenia gravis is presented. The disease was clinically established in a 71‐year‐old Japanese woman by an electromyographic, pharmachologic test and anti‐acetylcholine receptor (anti‐AChR) antibodies demonstrated in the circulating blood. The coexistence of Hashimotos thyroiditis was diagnosed by the presence of a diffuse thyroid enlargement, anti‐thyroglobulin and anti‐microsomal antibodies and a lowered thyroidal 131I uptake. A delusion of persecution developed during the treatment with pyridostigmine and ephedrine chloride, but the symptom disappeared after discontinuing the use of ephedrine chloride.

Unique Behavioral Change with Cinepazide in Parkinsonism

A 56-year-old male parkinsonian patient developed a unique behavioral change following the oral administration of cinepazide, a cerebral vasodilator. This behavior consisted of an apparent infatuation