Some are psychological, i.e. the fear response causes them to faint, or physical, such as the fainting that occurs when we over exert ourselves. Vagal nerve fainting (also known as vasovagal syncope) is quite simply any loss of consciousness caused by the vagus nerve. The vagus nerve runs directly from the brain stem, in front of the ears and down the neck towards the chest and abdomen. It branches off in several places to provide communication with the brain to a number of organs, such as the heart and the stomach.
The floor of the third ventricle is formed by a number of structures including the hypothalamus, subthalamus, mammilary bodies, infundibulum (pituitary stalk), and the tectum of the midbrain. The lateral walls of the third ventricle are formed by the walls of the left and right thalamus.
The paraventricular nucleus lies adjacent to the third ventricle, from which it derives its name, paraventricular meaning alongside a ventricle.. It does lie within the periventricular zone and must not be confused with the periventricular nucleus, which occupies a more medial position, beneath the third ventricle.mong these, inputs from neurons in structures adjacent to the anterior wall of the third ventricle (the AV3V region) carry information about the electrolyte composition of the blood, and about circulating concentrations of such hormones as angiotensin and relaxin, to regulate the magnocellular neurons.