|Brain: Subfornical organ|
|Mesal aspect of a brain sectioned in the median sagittal plane. (Subfornical organ not labeled, but fornix and foramen of Monro are both labeled near the center.)|
Relations with other circumventricular organs
The OVLT and the SFO are both strongly interconnected with the nucleus medianus, and together these three structures comprise the so called "AV3V" region - the region anterior and ventral to the third ventricle. The AV3V region is very important in the regulation of fluid and electrolyte balance, by controlling thirst, sodium excretion, blood volume regulation, and vasopressin secretion.
The SFO is outside the blood-brain barrier, and so neurons in this region can respond to factors that are present in the systemic circulation.
Some neurons in the SFO are osmoreceptors, being sensitive to the osmotic pressure of the blood. These neurons project to the supraoptic nucleus and paraventricular nucleus to regulate the activity of vasopressin-secreting neurons. These neurons also project to the nucleus medianus (also called the median preoptic nucleus) which is involved in controlling thirst.
Neurons in the SFO have receptors for many hormones that circulate in the blood but which do not cross the blood-brain barrier, including angiotensin, atrial natriuretic hormone, endothelin and relaxin.
- ↑ Lind R, Johnson A (1982). "Subfornical organ-median preoptic connections and drinking and pressor responses to angiotensin II". J Neurosci 2 (8): 1043-51. PMID 7108583.
|Epithalamus||Pineal body • Habenula (Habenular nuclei) • Stria medullaris • Habenular trigone|
|Thalamus/nuclei||paired: AN • Ventral (VA/VL, VP/VPM/VPL) • Lateral (Pulvinar) • Metathalamus (MG, LG)
surface: reticulartracts to thalamus: Mammillothalamic tract • Thalamic fasciculus • Lenticular fasciculus • Ansa lenticularis • Medial lemniscus • Trigeminal lemniscus • Spinothalamic tract • Lateral lemniscus
|Hypothalamus||autonomic zones: Anterior (parasympathetic/heat loss) • Posterior (sympathetic/heat conservation)
tracts: Medial forebrain bundlePituitary: (Posterior is diencephalon, but anterior is glandular)
|Subthalamus||Subthalamic nucleus • Zona incerta|
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