Abnormal regional cerebral blood flow (rCBF) and grey matter volume have been frequently reported in patients with major depressive disorder (MDD). However, it is unclear to what extent structural and functional change co-occurs in patients with MDD and whether markers of neural activity, such as rCBF, can be predicted by structural change. Using MRI, we investigated resting-state rCBF and brain structure in patients with MDD and healthy controls between July 2008 and January 2013. We acquired perfusion images obtained with continuous arterial spin labelling, used voxel-based morphometry to assess grey matter volume and integrated biological parametric mapping analyses to investigate the impact of brain atrophy on rCBF. We included 43 patients and 29 controls in our study. Frontotemporal grey matter volume was reduced in patients compared with controls. In patients, rCBF was reduced in the anterior cingulate and bilateral parahippocampal areas and increased in frontoparietal and striatal regions. These abnormalities were confirmed by analyses with brain volume as a covariate. In patients with MDD there were significant negative correlations between the extent of depressive symptoms and bilateral parahippocampal rCBF. We found a positive correlation between depressive symptoms and rCBF for right middle frontal cortical blood flow. Medication use in patients has to be considered as a limitation of our study. Our data suggest that while changes of cerebral blood flow and brain volume co-occur in patients with MDD, structural change is not sufficient to explain altered neural activity in patients at rest. Abnormal brain structure and function in patients with MDD appear to reflect distinct levels of neuropathology.

Cortico-hypoglossal projections were investigated in II patients with unifocal ischaemic lesions of different brainstem levels using transcranial magnetic stimulation. Lesion topography was documented by MRI studies. In seven patients the projections to the ipsi- and contralateral hypoglossal nuclei were separately affected. Pontine lesions at the ventral paramedian base close to the midline affect the contralateral projections while lateral lesions at the pontine base affect the ipsilateral projections. Lesions of the paramedian dorsal pontine base do not involve the cortico-hypoglossal projections. Our findings indicate that the cortico-hypoglossal fibres branch off the main ventral pyramidal tract. Lesions of the dorso- and mediolateral medulla impair only the ipsilateral projections. We conclude that ipsilateral projections enter the hypoglossal nucleus from its lateral aspect and that the contralateral projections cross the midline at the pontomedullary junction.

The neurophysiologic mechanisms involved in nonorganic paralysis are unclear. Because there is no established standard therapy, the authors investigated the effect of repetitive transcranial magnetic stimulation (rTMS) in four patients with nonorganic limb paralysis. Within the framework of a treatment trial, the patients were treated over a period of 5–12 weeks with rTMS applied to the contralateral motor cortex. Stimulation frequency was 15 Hz, train length 2 seconds, intertrain interval 4 seconds; daily total number of stimuli 4000. In one patient, motor function was completely restored; two patients experienced a marked improvement correlating with rTMS treatment. By contrast, one patient who had been diagnosed as a malingerer did not improve. Apart from possible favorable psychological factors that could partly explain the rTMS-associated effects, high-frequency rTMS might have enhanced or substituted an insufficient input to the motor cortex from failing frontal executive areas, and thereby opened the way to a learning process that lead to the reacquisition of limb use. rTMS may have a therapeutic effect in motor conversion disorder and may help elucidate neurophysiologic aspects of this condition. The potential benefit of rTMS in motor conversion disorder should be evaluated in larger, controlled samples.