wiki笔记--Septal area--2022/3/28

Septal area

Anatomical terms of neuroanatomy

[edit on Wikidata]

The septal area (medial olfactory area) is an area in the lower, posterior part of the medial surface of the frontal lobe, and refers to the nearby septum pellucidum.

The septal nuclei are located in this area. The septal nuclei are composed of medium-size neurons which are classified into dorsal, ventral, medial, and caudal groups.[1] The septal nuclei receive reciprocal connections from the olfactory bulb, hippocampus, amygdala, hypothalamus, midbrain, habenula, cingulate gyrus, and thalamus. The septal nuclei are essential in generating the theta rhythm of the hippocampus.

The septal area (medial olfactory area) has no relation to the sense of smell, but it is considered a pleasure zone in animals. The septal nuclei play a role in reward and reinforcement along with the nucleus accumbens(因为lateral septal area投射到VTA). In the 1950s, Olds & Milner showed that rats with electrodes implanted in this area will self-stimulate repeatedly (i.e., press a bar to receive electrical current that stimulate the neurons).[2]Experiments on the septal area of humans have taken place since the 1960s.[3][4][5][6]

Contents

1Connections

1.1Lateral septum and social behavior

2References

3External links

Connections[edit]

Detail of drawing showing components of septal area below corpus callosum.

The septal area is located on the lower posterior part of the frontal lobe. The septal area refers to the nearby septum pellucidum. It is located underneath the corpus callosum and in front of the lamina terminalis. The lamina terminalis is a layer of gray matter that connects the optic chiasma and the anterior commissure.[7] The septal nuclei are in the septal area, and are essential in generating the theta rhythm of the hippocampus.[8]

The dorsal septum projects to the lateral preoptic area, lateral hypothalamus, periventricular hypothalamus and midline thalamus

（dorsal septum投射到midline thalamus，这意味着dorsal septum涉及对疼痛的调节；投射到lateral preoptic area，意味着dorsal septum涉及对睡眠的调节；投射到lateral hypothalamus，意味着dorsal septum涉及对饮食的调节。）.

Fibers from the ventral half of the septum project topographically to the hippocampal formation, thalamus, hypothalamus and midbrain

（这里不应该是medial septal nucleus吗？难道ventral half of the septum是diagonal band of Broca？这个猜想倒是和本段后面的内容达成一致。）

. Specifically, neurons located along the midline in the vertical limb of the diagonal band of Broca project through the dorsal fornix to all CA fields of the dorsal hippocampus and adjacent subicular cortex. Other fibers from this region project through the stria medullaris to the medial and lateral habenular nuclei, the paratenial and anteromedial nucleus of the thalamus

(这句话对medial and lateral habenular nuclei的描述不清晰，基本等于无用；而paratenial and anteromedial nucleus of the thalamus也是涉及疼痛。这一段内容好像是在描述diagonal band of Broca，难道ventral half of the septum是diagonal band of Broca？)

, and through the medial forebrain bundle to the pars posterior of the medial mammillary nucleus.

Cells located in the intermediolateral septum also project through the lateral part of the fimbria to all CA fields of the ventral hippocampus and adjacent subicular and entorhinal cortices（这里好像说的是medial septal nucleus。但是为什么不用通用的说法呢？）. These cells also send fibers through the stria medullaris to the lateral habenular nucleus and mediodorsal thalamic nucleus. Other axons arising from these cells descend through the medial forebrain bundle to terminate in a region dorsal to the interpeduncular nucleus.

The lateral septum is a relay center for connections from the CA3 of the hippocampus to the ventral tegmental area.

（本词条中所有内容，只有这句话是描述最明确的，最有用的，说明只有CA3的活动是可以通过lateral septum兴奋VTA。） 

These connections help link reward signals with the context in which they occur.[9]

Fibers from the most lateral part of the ventral septum (i.e., bed nucleus of the anterior commissure) project through the stria terminalis to the ventral subiculum. In addition, cells located in the horizontal limb of the diagonal band project massively to the pars posterior of the medial mammillary nucleus, the ventral tegmental area, and amygdala.

Lateral septum and social behavior[edit]

Inhibitory GABA, and excitatory glutamate, which regulate lateral septum (LS) activity, have been found to be increased during social play in juvenile rats. No sex differences were found in extracellular GABA concentrations during social playing, however, glutamate plays a major role in female social playing. When glutamate receptors are blocked in the LS pharmacologically, there is a significant decrease in female social playing, while males had no decrease in playing. This suggests that in the lateral septum, GABA neurotransmission is involved in social play behavior regulation in both sexes, while glutamate neurotransmission is sex-specific, involved in regulation of social play only in female juvenile rats.[10]

总的来说，这是一个描述不清，以及一定程度混乱的词条，估计是现有的研究成果远没有弄清楚其功能吧，但是为什么词条中连起码的连接结构都描述得如此模糊，这解剖学上的知识不应该是科研难点啊。所以，septal area的连接结构和功能还不清楚，有待我去进一步确定。虽然常规的科学手段难以确定其功能，但是我有很多线索去研究septal area，比如它投射到海马区域，那么就可以通过海马区域活动时对应的行为去研究，还比如它投射到interpeduncular nucleus和habenular nucleus，那么就可以用对应的行为特征去研究。