Septal area

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Septal area
Mouse Septal Nuclei.pdf
Lateral and medial septal nuclei in the septal area of the mouse brain
Details
Identifiers
Latin nuclei septales
MeSH D012686
NeuroNames 259
TA98 A14.1.09.266
TA2 5548
FMA 61845
Anatomical terms of neuroanatomy

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

Contents

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. In the 1950s, Olds & Milner showed that rats with electrodes implanted in this area will self-stimulate repeatedly (e.g., press a bar to receive electric current that stimulate the neurons). [2] Experiments on the septal area of humans have taken place since the 1960s. [3] [4] [5] [6]

Connections

Detail of drawing showing components of septal area below corpus callosum. Septal area below the corpus callosum.jpg
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 in the septal area 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.

Fibers from the ventral half of the septum project topographically to the hippocampal formation, thalamus, hypothalamus and midbrain. 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, 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. 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. [9] [10] These connections help link reward signals with the context in which they occur. [11] [12]

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. [13] 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.

Functions of the lateral septum

The lateral septum and movement and reward

The lateral septum is involved in a variety of functions, including emotional, motivational, and spatial behavior. It has been suggested that the LS may regulate interactions between the hippocampus and other regions that mediate goal directed behavior, such as the ventral tegmental area. [14] [15] Firing of LS neurons is modulated by both speed and acceleration [16] and spatial location, and that firing is also related to reward and context. [14] [17] It has thus been suggested that the lateral septum may incorporate movement into the evaluation of environmental context with respect to motivation and reward. [10]

Lateral septum and social behavior

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. [18]

Lateral septum and reproduction

Experiments [19] [20] have shown that both testosterone and dihydrotestosterone, when implanted directly into the lateral septum of male rats, caused a significant rise in serum LH and FSH levels, while not significantly increasing serum testosterone and dihydrotestosterone levels respectively. This indicates that the effect is occurring through testosterone receptors and independently of conversion to estrogen via aromatization. As of now, it is unclear, what exact pathway is mediating this phenomenon. Septal lesions significantly decreased serum LH and testosterone levels in male rats, while FSH and prolactin production were unaffected by the surgery. Electrical stimulation of the septum induced the elevation of serum LH and FSH levels. [21] These data suggest that the lateral and/or the medial septum may play a role in the control of GnRH/gonadotropin secretion, and thus, the reproductive axis.

Lateral septum and memory [22]

Despite the diverse direct projection system between the hippocampus and the lateral septum, the first pieces of evidence regarding the role of latter brain area in memory formation and retention have only started to emerge as of 2022. However, recent research has started to shed light on the potentially diverse roles of the lateral septum.

Social memory

The roles of the lateral septum in formation of social memories remain unclear and controversial. It is clear, that some role is being played, as oxytocin and vasopressin, when administered into the lateral septum after social training were able to enhance memory formation, [23] [24] while their respective receptor blockers had the opposite effect. [23] [25] However, data on effects of pre-training administration of these compounds is mixed, hence the lack of consensus.

Fear memory

Pieces of evidence suggesting the role the lateral septum could be playing in fear memory formation and consolidation have started emerging at the end of the XX. century. [26] Inhibitory avoidance tasks using footshock chambers on mice were deployed to study the effects of the disruption of the lateral septum and hippocampal inputs on fear memory formation and retrieval respectively. [27] [28] In both cases, fear memory formation/retrieval was impaired, supporting the hypothesis that hippocampal projections to the lateral septum are at least in part responsible for these mechanisms. The lateral septum could also prove essential in fear memory consolidation. Post-shock adminitration of CRF into the lateral septum enhanced fear memory in the relelvant context; [29] however, this finding still needs to be supported by further studies.

Related Research Articles

<span class="mw-page-title-main">Hippocampus</span> Vertebrate brain region involved in memory consolidation

The hippocampus is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. The hippocampus is located in the allocortex, with neural projections into the neocortex, in humans as well as other primates. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In humans, it contains two main interlocking parts: the hippocampus proper, and the dentate gyrus.

<span class="mw-page-title-main">Limbic system</span> Set of brain structures involved in emotion and motivation

The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.

<span class="mw-page-title-main">Fornix (neuroanatomy)</span> Bundle of nerve fibers in the brain

The fornix is a C-shaped bundle of nerve fibers in the brain that acts as the major output tract of the hippocampus. The fornix also carries some afferent fibers to the hippocampus from structures in the diencephalon and basal forebrain. The fornix is part of the limbic system. While its exact function and importance in the physiology of the brain are still not entirely clear, it has been demonstrated in humans that surgical transection—the cutting of the fornix along its body—can cause memory loss. There is some debate over what type of memory is affected by this damage, but it has been found to most closely correlate with recall memory rather than recognition memory. This means that damage to the fornix can cause difficulty in recalling long-term information such as details of past events, but it has little effect on the ability to recognize objects or familiar situations.

<span class="mw-page-title-main">Ventral tegmental area</span> Group of neurons on the floor of the midbrain

The ventral tegmental area (VTA), also known as the ventral tegmental area of Tsai, or simply ventral tegmentum, is a group of neurons located close to the midline on the floor of the midbrain. The VTA is the origin of the dopaminergic cell bodies of the mesocorticolimbic dopamine system and other dopamine pathways; it is widely implicated in the drug and natural reward circuitry of the brain. The VTA plays an important role in a number of processes, including reward cognition and orgasm, among others, as well as several psychiatric disorders. Neurons in the VTA project to numerous areas of the brain, ranging from the prefrontal cortex to the caudal brainstem and several regions in between.

<span class="mw-page-title-main">Subiculum</span> Most inferior part of the hippocampal formation

The subiculum is the most inferior component of the hippocampal formation. It lies between the entorhinal cortex and the CA1 subfield of the hippocampus proper.

<span class="mw-page-title-main">Habenula</span> Small bilateral neuronal structure in the brain of vertebrates

The habenula is a small bilateral neuronal structure in the brain of vertebrates, that has also been called a microstructure since it is no bigger than a pea. The naming as little rein describes its elongated shape in the epithalamus, where it borders the third ventricle, and lies in front of the pineal gland.

Theta waves generate the theta rhythm, a neural oscillation in the brain that underlies various aspects of cognition and behavior, including learning, memory, and spatial navigation in many animals. It can be recorded using various electrophysiological methods, such as electroencephalogram (EEG), recorded either from inside the brain or from electrodes attached to the scalp.

<span class="mw-page-title-main">Median raphe nucleus</span> Brain region having polygonal, fusiform, piriform neurons

The median raphe nucleus, also known as the nucleus raphes medianus (NRM) or superior central nucleus, is a brain region composed of polygonal, fusiform, and piriform neurons, which exists rostral to the nucleus raphes pontis. The MRN is located between the posterior end of the superior cerebellar peduncles and the V. Afferents of the motor nucleus. It is one of two nuclei, the other being the dorsal raphe nucleus (DnR), in the midbrain-pons.

<span class="mw-page-title-main">Medial forebrain bundle</span>

The medial forebrain bundle (MFB) is a neural pathway containing fibers from the basal olfactory regions, the periamygdaloid region and the septal nuclei, as well as fibers from brainstem regions, including the ventral tegmental area and nigrostriatal pathway.

<span class="mw-page-title-main">Diagonal band of Broca</span>

The diagonal band of Broca interconnects the amygdala and the septal area. It is one of the olfactory structures. It is situated upon the inferior aspect of the brain. It forms the medial margin of the anterior perforated substance.

<span class="mw-page-title-main">Preoptic area</span> Region of the anterior hypothalamus

The preoptic area is a region of the hypothalamus. MeSH classifies it as part of the anterior hypothalamus. TA lists four nuclei in this region,.

The trisynaptic circuit or trisynaptic loop is a relay of synaptic transmission in the hippocampus. The circuit was initially described by the neuroanatomist Santiago Ramon y Cajal, in the early twentieth century, using the Golgi staining method. After the discovery of the trisynaptic circuit, a series of research has been conducted to determine the mechanisms driving this circuit. Today, research is focused on how this loop interacts with other parts of the brain, and how it influences human physiology and behaviour. For example, it has been shown that disruptions within the trisynaptic circuit lead to behavioural changes in rodent and feline models.

<span class="mw-page-title-main">Hippocampus anatomy</span> Component of brain anatomy

Hippocampus anatomy describes the physical aspects and properties of the hippocampus, a neural structure in the medial temporal lobe of the brain. It has a distinctive, curved shape that has been likened to the sea-horse monster of Greek mythology and the ram's horns of Amun in Egyptian mythology. This general layout holds across the full range of mammalian species, from hedgehog to human, although the details vary. For example, in the rat, the two hippocampi look similar to a pair of bananas, joined at the stems. In primate brains, including humans, the portion of the hippocampus near the base of the temporal lobe is much broader than the part at the top. Due to the three-dimensional curvature of this structure, two-dimensional sections such as shown are commonly seen. Neuroimaging pictures can show a number of different shapes, depending on the angle and location of the cut.

<span class="mw-page-title-main">Pallium (neuroanatomy)</span> Layers of grey and white matter that cover the upper surface of the cerebrum in vertebrates

In neuroanatomy, pallium refers to the layers of grey and white matter that cover the upper surface of the cerebrum in vertebrates. The non-pallial part of the telencephalon builds the subpallium. In basal vertebrates, the pallium is a relatively simple three-layered structure, encompassing 3–4 histogenetically distinct domains, plus the olfactory bulb.

<span class="mw-page-title-main">Medial septal nucleus</span>

The medial septal nucleus (MS) is one of the septal nuclei. Neurons in this nucleus give rise to the bulk of efferents from the septal nuclei. A major projection from the medial septal nucleus terminates in the hippocampal formation.

The ventral pallidum (VP) is a structure within the basal ganglia of the brain. It is an output nucleus whose fibres project to thalamic nuclei, such as the ventral anterior nucleus, the ventral lateral nucleus, and the medial dorsal nucleus. The VP is a core component of the reward system which forms part of the limbic loop of the basal ganglia, a pathway involved in the regulation of motivational salience, behavior, and emotions. It is involved in addiction.

<span class="mw-page-title-main">Septum verum</span> Region of the brain

Septum Verum is a region in the lower medial part of the telencephalon that separates the two cerebral hemispheres. The human septum consists of two parts: the septum pellucidum, a thin membrane consisting of white matter and glial cells that separate the lateral ventricles, and the lower, precommisural septum verum, which consists of nuclei and grey matter. The term is sometimes used synonymously with Area Septalis, to refer to the precommisural part of the lower base of the telencephalon. The Septum verum contains the septal nuclei, which are usually considered part of the limbic system. 

The dorsal tegmental nucleus (DTN), also known as dorsal tegmental nucleus of Gudden (DTg), is a group of neurons located in the brain stem, which are involved in spatial navigation and orientation.

The supramammillary nucleus (SuM), or supramammillary area, is a thin layer of cells in the brain that lies above the mammillary bodies. It can be considered part of the hypothalamus and diencephalon. The nucleus can be divided into medial and lateral sections. The medial SuM, or SuMM, is made of smaller cells which release dopamine and give input to the lateral septal nucleus. The lateral SuM, or SuML, is made of larger cells that project to the hippocampus.

References

  1. ↑ St-Amant, Maxime. "Septal nuclei | Radiology Reference Article | Radiopaedia.org". Radiopaedia. Retrieved 23 October 2019.
  2. ↑ Olds J, Milner P (1954). "Positive reinforcement produced by electrical stimulation of septal area and other regions of rat brain". Journal of Comparative and Physiological Psychology. 47 (6): 419–27. doi:10.1037/h0058775. PMID   13233369 . Retrieved 17 March 2013.
  3. ↑ Heath RG (1963). "Electrical self-stimulation of the brain in man". The American Journal of Psychiatry. 120 (6): 571–577. doi:10.1176/ajp.120.6.571. ISSN   0002-953X. PMID   14086435.
  4. ↑ Moan CE, Heath RG (1972). "Septal stimulation for the initiation of heterosexual behavior in a homosexual male". Journal of Behavior Therapy and Experimental Psychiatry. 3 (1): 23–30. doi:10.1016/0005-7916(72)90029-8. ISSN   0005-7916.
  5. ↑ Szalavitz, Maia. "Controversial Surgery for Addiction Burns Away Brain's Pleasure Center". Time. ISSN   0040-781X . Retrieved 4 May 2018.
  6. ↑ Zamiska, Nicholas (28 April 2008). "China Bans Irreversible Brain Procedure" . Wall Street Journal. ISSN   0099-9660 . Retrieved 4 May 2018.
  7. ↑ Gaillard, Frank. "Septal area | Radiology Reference Article | Radiopaedia.org". Radiopaedia. Retrieved 21 October 2019.
  8. ↑ Butler, T (15 August 2014). "Comparison of human septal nuclei MRI measurements using automated segmentation and a new manual protocol based on histology". NeuroImage. 97: 245–51. doi:10.1016/j.neuroimage.2014.04.026. PMC   4180657 . PMID   24736183.
  9. ↑ Wirtshafter, Hannah S.; Wilson, Matthew A. (2020-05-26). "Differences in reward biased spatial representations in the lateral septum and hippocampus". eLife. 9: e55252. doi: 10.7554/eLife.55252 . ISSN   2050-084X. PMC   7274787 . PMID   32452763.
  10. 1 2 Wirtshafter, Hannah S.; Wilson, Matthew A. (July 2021). "Lateral septum as a nexus for mood, motivation, and movement". Neuroscience and Biobehavioral Reviews. 126: 544–559. doi: 10.1016/j.neubiorev.2021.03.029 . ISSN   1873-7528. PMID   33848512. S2CID   233202402.
  11. ↑ Wirtshafter HS, Wilson MA (July 2021). "Lateral Septum as a Nexus for Mood, Motivation, and Movement". Neuroscience & Biobehavioral Reviews. 126: 544–559. doi: 10.1016/j.neubiorev.2021.03.029 . PMID   33848512. S2CID   233202402.
  12. ↑ Luo AH, Tahsili-Fahadan P, Wise RA, Lupica CR, Aston-Jones G (14 July 2011). "Linking Context with Reward: A Functional Circuit from Hippocampal CA3 to Ventral Tegmental Area". Science. 333 (6040): 353–357. Bibcode:2011Sci...333..353L. doi:10.1126/science.1204622. PMC   3150711 . PMID   21764750.
  13. ↑ Risold, P. Y.; Swanson, L. W. (1997-09-19). "Connections of the rat lateral septal complex". Brain Research. Brain Research Reviews. 24 (2–3): 115–195. doi:10.1016/s0165-0173(97)00009-x. PMID   9385454. S2CID   30199261.
  14. 1 2 Wirtshafter, Hannah S.; Wilson, Matthew A. (2020-05-26). "Differences in reward biased spatial representations in the lateral septum and hippocampus". eLife. 9. doi: 10.7554/eLife.55252 . ISSN   2050-084X. PMC   7274787 . PMID   32452763.
  15. ↑ Jiang, Jin-Xiang; Liu, Huan; Huang, Zhen-Zhen; Cui, Yue; Zhang, Xue-Qin; Zhang, Xiao-Long; Cui, Yu; Xin, Wen-Jun (January 2018). "The role of CA3-LS-VTA loop in the formation of conditioned place preference induced by context-associated reward memory for morphine: Role of LSc in morphine reward". Addiction Biology. 23 (1): 41–54. doi:10.1111/adb.12468. PMID   27862708. S2CID   2572656.
  16. ↑ Wirtshafter, Hannah S.; Wilson, Matthew A. (October 2019). "Locomotor and Hippocampal Processing Converge in the Lateral Septum". Current Biology. 29 (19): 3177–3192.e3. doi: 10.1016/j.cub.2019.07.089 . PMID   31543450.
  17. ↑ Wirtshafter, Hannah S.; Wilson, Matthew A. (2019-10-07). "Locomotor and Hippocampal Processing Converge in the Lateral Septum". Current Biology. 29 (19): 3177–3192.e3. doi: 10.1016/j.cub.2019.07.089 . ISSN   1879-0445. PMID   31543450.
  18. ↑ Bredewold R, Schiavo JK, van der Hart M, Verreij M, Veenema AH (2015). "Dynamic changes in extracellular release of GABA and glutamate in the lateral septum during social play behavior in juvenile rats: Implications for sex-specific regulation of social play behavior". Neuroscience. 307: 117–27. doi:10.1016/j.neuroscience.2015.08.052. PMC   4591248 . PMID   26318330.
  19. ↑ Carreras, Alfonso; Mendoza, Carmen; Ortega, Esperanza; Ruiz, Estrella (1987-07-01). "Testosterone implants into the lateral septum of male rats, a positive effect on LH and FSH secretion". Brain Research Bulletin. 19 (1): 149–151. doi:10.1016/0361-9230(87)90179-1. ISSN   0361-9230. PMID   3115497. S2CID   13489400.
  20. ↑ Roca, G. (July 7, 2009). "Crystalline Dihydrotestosterone Implants in the Lateral Septum of Male Rats. A Positive Effect on Lh and FSH". Endocrine Research. 27 (1–2): 35–40. doi:10.1081/ERC-100107167. PMID   11428719. S2CID   38059247 . Retrieved December 11, 2022.
  21. ↑ Carreras, A.; Robles, R.; Ruiz, E.; Ortega, E.; Mendoza, C.; Osorio, C. (1984-08-01). "Role of the septum on LH, FSH and prolactin secretion in male rats". Brain Research Bulletin. 13 (2): 339–342. doi:10.1016/0361-9230(84)90136-9. ISSN   0361-9230. PMID   6437605. S2CID   8531335.
  22. ↑ Rizzi-Wise, Candace A.; Wang, Dong V. (2021-11-01). "Putting Together Pieces of the Lateral Septum: Multifaceted Functions and Its Neural Pathways". eNeuro. 8 (6). doi:10.1523/ENEURO.0315-21.2021. ISSN   2373-2822. PMC   8647703 . PMID   34764187.
  23. 1 2 Dantzer, Robert; Koob, George F.; Bluthe´, Rose-Marie; Le Moal, Michel (1988-08-02). "Septal vasopressin modulates social memory in male rats". Brain Research. 457 (1): 143–147. doi:10.1016/0006-8993(88)90066-2. ISSN   0006-8993. PMID   3167559. S2CID   32037924.
  24. ↑ P. Popik 1, P.E. Vos, J.M. Van Ree Behav Pharmacol 1992 Aug;3(4):351-358. Neurohypophyseal hormone receptors in the septum are implicated in social recognition in the rat PMID 11224137
  25. ↑ Lukas, Michael; Toth, Iulia; Veenema, Alexa H.; Neumann, Inga D. (2013-06-01). "Oxytocin mediates rodent social memory within the lateral septum and the medial amygdala depending on the relevance of the social stimulus: Male juvenile versus female adult conspecifics". Psychoneuroendocrinology. 38 (6): 916–926. doi:10.1016/j.psyneuen.2012.09.018. ISSN   0306-4530. PMID   23102690. S2CID   43827714.
  26. ↑ Desmedt, Aline; Garcia, René; Jaffard, Robert (1999-11). "Vasopressin in the lateral septum promotes elemental conditioning to the detriment of contextual fear conditioning in mice: Vasopressin in the LS promotes elemental conditioning". European Journal of Neuroscience. 11 (11): 3913–3921. doi:10.1046/j.1460-9568.1999.00815.x.
  27. ↑ Opalka, Ashley N.; Wang, Dong V. (2020-08-01). "Hippocampal efferents to retrosplenial cortex and lateral septum are required for memory acquisition". Learning & Memory. 27 (8): 310–318. doi:10.1101/lm.051797.120. ISSN   1072-0502. PMC   7365017 . PMID   32669386.
  28. ↑ Besnard, Antoine; Gao, Yuan; TaeWoo Kim, Michael; Twarkowski, Hannah; Reed, Alexander Keith; Langberg, Tomer; Feng, Wendy; Xu, Xiangmin; Saur, Dieter; Zweifel, Larry S.; Davison, Ian; Sahay, Amar (2019). "Dorsolateral septum somatostatin interneurons gate mobility to calibrate context-specific behavioral fear responses". Nature Neuroscience. 22 (3): 436–446. doi:10.1038/s41593-018-0330-y. ISSN   1097-6256. PMC   6387640 . PMID   30718902.
  29. ↑ E H Lee (1995) Chin J Physiol Corticotropin-releasing factor injected into the lateral septum improves memory function in rats 1995;38(3):200 PMID 8697897
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