Optic flow stimuli update anterodorsal thalamus head direction neuronal activity in rats.

Head direction (HD) neurons fire selectively according to head orientation in the yaw plane relative to environmental landmark cues. Head movements provoke optic field flow signals that enter the vestibular nuclei, indicating head velocity, and hence angular displacements. To test whether optic field flow alone affects the directional firing of HD neurons, rats walked about on a circular platform as a spot array was projected onto the surrounding floor-to-ceiling cylindrical black curtain.

[Right intraventricular tumors. Apropos of a case].

The authors report a case of right ventricular tumour in a 16 year old girl who presented with dyspnoea on effort, chest pain on exertion and loss of consciousness. The diagnosis was made on the basis of abnormal right intraventricular echoes on two dimensional echocardiography and was confirmed by angiography. The patient was operated with success.

[Right pulmonary artery-left atrial fistula. Review of the literature apropos of a case].

This is a rare congenital abnormality with only 17 other reported cases in the world literature. The most frequent sign is cyanosis with peripheral arterial desaturation. Angiography with selective injection in the main pulmonary shows early opacification of the left atrium, so confirming the diagnosis.