What is the locus coeruleus in the brain?
The locus coeruleus, which appears to mean “blue spot” in Latin, is the primary site in the brain for norepinephrine production (noradrenaline). The locus coeruleus and the parts of the body impacted by the norepinephrine it generates are referred to as the locus coeruleus-noradrenergic system, abbreviated as the LC-NA system.
What is the norepinephrine locus coeruleus?
The locus coeruleus (or “blue spot”) interacts with the amygdala, a group of cells near the brain responsible for emotional interpretation It is the primary source of noradrenaline, a neurotransmitter in the brain The norepinephrine (NE) locus coeruleus (LC) framework is implicated in the control of waking and sleeping processes.
What regions of the brain are part of the limbic system?
The brain regions that constitute the limbic system are: Limbic cortex Cingulate gyrus Hippocampal formation The dentate gyrus Amygdala Septal area Hypothalamus
Why is the locus coeruleus highlighted in Green?
Locus coeruleus highlighted in green. The locus coeruleus (LC) is located in the posterior area of the rostral pons in the lateral floor of the fourth ventricle. It is composed of mostly medium-size neurons. Melanin granules inside the neurons of the LC contribute to its blue colour.
Is locus coeruleus in thalamus?
Locus coeruleus (LC) sends widespread outputs to many brain regions to modulate diverse functions, including sleep/wake states, attention, and the general anesthetic state. The paraventricular thalamus (PVT) is a critical thalamic area for arousal and receives dense tyrosine-hydroxylase (TH) inputs from the LC.
Is the locus coeruleus in the amygdala?
The locus coeruleus innervates almost the entire forebrain, with the exception of the striatum Figure 1: it projects to the entire neocortex, the thalamus, limbic structures such as the amygdala and the hippocampus, the pallidum and the cerebellum, as well as other neuromodulatory nuclei controlling the release of ...
Is the locus coeruleus part of the midbrain?
The locus coeruleus (/sɪˈruːliəs/) (LC), also spelled locus caeruleus or locus ceruleus, is a nucleus in the pons of the brainstem involved with physiological responses to stress and panic. It is a part of the reticular activating system.
What part of the brain is the locus coeruleus?
The locus coeruleus (LC), or 'blue spot', is a small nucleus located deep in the brainstem that provides the far-reaching noradrenergic neurotransmitter system of the brain.
What is the limbic brain?
The limbic system is the part of the brain involved in our behavioural and emotional responses, especially when it comes to behaviours we need for survival: feeding, reproduction and caring for our young, and fight or flight responses.
Which attention system are locus coeruleus neurons associated?
The locus coeruleus It is the brain's main source of the neurotransmitter noradrenaline (norepinephrine). This chemical is excitatory and is released in response to pain or stress, stimulating what is referred to as the 'fight-or-flight' mechanism. This means that it activates the sympathetic nervous system.
What is the locus coeruleus?
The locus coeruleus (LC), a small brainstem nucleus, is the primary source of the neuromodulator norepinephrine (NE) in the brain. The LC receives input from widespread brain regions, and projects throughout the forebrain, brainstem, cerebellum, and spinal cord.
What happens if locus coeruleus is damaged?
Correspondingly, we have shown that locus coeruleus lesion leads to disorganization of tight junctions in cerebral endothelial cells (Kalinin et al., 2006a). Locus coeruleus damage could therefore increase infiltration of activated lymphocytes and exacerbation of disease.
What does locus coeruleus mean?
Definition of locus coeruleus : a bluish area of the brain stem with many norepinephrine-containing neurons.
What stimulates locus coeruleus?
The locus coeruleus (LC) is the major noradrenergic nucleus and sends projections to almost all brain areas. A marked increase in norepinephrine release has been demonstrated in several brain areas in response to exposure to acute stressful stimuli, especially those innervated by LC projections.
What is the role of the locus coeruleus in the stress response?
The locus coeruleus (LC) is a major node in the stress response that integrates input from multiple stress responsive neural circuits and releases norepinephrine (NE) throughout the central nervous system (CNS) to promote vigilance and anxiety.
Where does the locus coeruleus project to?
The locus coeruleus (LC), a small brainstem nucleus, is the primary source of the neuromodulator norepinephrine (NE) in the brain. The LC receives input from widespread brain regions, and projects throughout the forebrain, brainstem, cerebellum, and spinal cord.
What is the role of the locus coeruleus in the stress response?
The locus coeruleus (LC) is a major node in the stress response that integrates input from multiple stress responsive neural circuits and releases norepinephrine (NE) throughout the central nervous system (CNS) to promote vigilance and anxiety.
Where is norepinephrine made in the brain?
As a neurotransmitter, norepinephrine is made from dopamine. Norepinephrine is made from nerve cells in the brainstem area of your brain and in an area near your spinal cord.
What happens if locus coeruleus is damaged?
Correspondingly, we have shown that locus coeruleus lesion leads to disorganization of tight junctions in cerebral endothelial cells (Kalinin et al., 2006a). Locus coeruleus damage could therefore increase infiltration of activated lymphocytes and exacerbation of disease.
What is the role of the locus coeruleus in the brain?
The locus coeruleus is responsible for mediating many of the sympathetic effects during stress . The locus coeruleus is activated by stress, and will respond by increasing norepinephrine secretion, which in turn will alter cognitive function (through the prefrontal cortex), increase motivation (through nucleus accumbens ), activate the hypothalamic-pituitary-adrenal axis, and increase the sympathetic discharge /inhibit parasympathetic tone (through the brainstem ). Specific to the activation of the hypothalamic-pituitary adrenal axis, norepinephrine will stimulate the secretion of corticotropin-releasing factor from the hypothalamus, that induces adrenocorticotropic hormone release from the anterior pituitary and subsequent cortisol synthesis in the adrenal glands. Norepinephrine released from locus coeruleus will feedback to inhibit its production, and corticotropin-releasing factor will feedback to inhibit its production, while positively feeding to the locus coeruleus to increase norepinephrine production.
What is the locus coeruleus?
The locus coeruleus, which in Latin means "blue spot", is the principal site for brain synthesis of norepinephrine (noradrenaline). The locus coeruleus and the areas of the body affected by the norepinephrine it produces are described collectively as the locus coeruleus-noradrenergic system or LC-NA system.
Which neurotransmitter is used in the locus coeruleus?
The projections from the locus coeruleus consist of neurons that utilize norepinephrine as their primary neurotransmitter. These projections include the following connections:
Where does the noradrenergic neuronal pathway originate?
Psychiatric research has documented that enhanced noradrenergic postsynaptic responsiveness in the neuronal pathway (brain circuit) that originates in the locus coeruleus and ends in the basolateral nucleus of the amygdala is a major factor in the pathophysiology of most stress-induced fear-circuitry disorders and especially in posttraumatic stress disorder (PTSD). The LC neurons are probably the origin of the first or second "leg" of the "PTSD circuit." An important 2005 study of deceased American army veterans from World War II has shown combat-related PTSD to be associated with a postmortem-diminished number of neurons in the locus coeruleus (LC) on the right side of the brain.
Where is the locus coeruleus located?
The locus coeruleus (LC) is located in the posterior area of the rostral pons in the lateral floor of the fourth ventricle. It is composed of mostly medium-size neurons. Melanin granules inside the neurons of the LC contribute to its blue colour. Thus, it is also known as the nucleus pigmentosus pontis, meaning "heavily pigmented nucleus ...
Which part of the brain receives inputs from a number of other brain regions?
The locus coeruleus receives inputs from a number of other brain regions, primarily:
Which body system innervates the locus coeruleus?
The cingulate gyrus and the amygdala also innervate the LC , allowing emotional pain and stressors to trigger noradrenergic responses.
Where are the locus coeruleus nuclei located?
The neurons forming the locus coeruleus complex are found throughout much of the rostrocaudal extent of the pons and are generally classified into five distinct nuclei, although the number and organization does differ across species ( Dell et al., 2010 ). The four most commonly reported nuclei are the compact portion of the subcoeruleus (A7sc), the diffuse portion of the subcoeruleus (A7d), the diffuse portion of the locus coeruleus (A6d), and the fifth arcuate nucleus (A5). The A7sc is observed as a tightly packed cluster of tyrosine hydroxylase immunopositive neurons adjacent to the ventrolateral border of the periventricular gray matter within the dorsolateral portion of the parvocellular pontine tegmentum. This nucleus was previously termed the subcoeruleus ( Dahlström and Fuxe, 1964 ). Ventral and lateral to this nucleus, a diffusely organized aggregation of tyrosine hydroxylase immunoreactive neurons forms the A7d nucleus. These neurons are found throughout the majority of the parvocellular pontine tegmentum rostral to the trigeminal motor nucleus and lateral to the superior cerebellar peduncle in the parabrachial region. Within the ventrolateral portion of the periventricular gray matter, often adjacent to or intermixed with the cholinergic LDT nucleus ( Manger et al., 2002c ), is what is often referred to as the locus coeruleus proper ( Dahlström and Fuxe, 1964 ), but, with further comparative studies, is now termed the diffuse portion of the locus coeruleus complex (A6d). The last commonly reported nucleus of the locus coeruleus complex is the fifth arcuate nucleus (A5). This nucleus is found in the ventrolateral pontine tegmentum, from the level of the fifth motor nucleus to the caudal border of the pons, in a position within the divisions of the superior olivary complex and ventrolateral and caudal to the facial nerve nuclear complex. The neurons within the A5 form a mesh-like dendritic network around the fascicles located within the ventrolateral parvocellular pontine tegmentum.
How many nuclei are in the locus coeruleus?
The neurons forming the locus coeruleus complex are found throughout much of the rostrocaudal extent of the pons and are generally classified into five distinct nuclei, although the number and organization does differ across species ( Dell et al., 2010 ).
What is the name of the brain's main source of neurotransmitter?
The locus coeruleus. The locus coeruleus (from the Latin for ‘blue spot') communicates closely with the amygdala. It is the brain's main source of the neurotransmitter noradrenaline (norepinephrine). This chemical is excitatory and is released in response to pain or stress, stimulating what is referred to as the ‘fight-or-flight’ mechanism.
Where does the locus coeruleus end?
The majority of axons arising from the LC terminate in the neocortex and hippocampus. 1–3 Half of all LC terminals end by contacting neurons, whereas the remaining half ends at microglial and astroglial cells forming “nonsynaptic” contacts. Activation of adrenergic receptors (ARs) on glial cells can elicit potent antiinflammatory actions, which help limit neuroinflammatory events throughout the central nervous system (CNS). LC-derived NA and β-ARs have also been implicated in the physiological modulation of memory formation and retrieval. 2,4–6
Where do LC/SC neurons project?
The LC/SC neurons project to the spinal cord. Initially, bulbospinal noradrenergic fibers are thought to originate from the A1 cell group in the caudal medulla ( Dahlström and Fuxe, 1964 ). Using combined dopamine–beta-hydroxylase immunohistochemistry and retrograde tracing, Westlund et al. (1983) demonstrated that brainstem descending noradrenergic fibers are exclusively from the pontine noradrenergic cell groups. In the rat, the LC and SC provide major descending noradrenergic axons to the spinal cord. These findings form the anatomical basis for a role of the LC/SC in descending control. One concern on the spinal projection of LC/SC neurons is that they apparently terminate most heavily in laminae VII, VIII, and IX of the ventral horn. The termination of LC fibers is moderate in the deep dorsal horn and relatively sparse in the superficial dorsal horn ( Clark and Proudfit, 1991 ). However, there appears to be a substrain difference in LC/SC descending projection related to the commercial sources. More lamina I terminations are from the LC in rats raised in Harlan Sprague-Dawley while the SC of Sasco source provides more lamina I projection ( Fritschy and Grzanna, 1990; Sluka and Westlund, 1992; Willis et al., 1995; Proudfit, 2002 ).
Which neuron sends collateral branches to the cerebellum?
There is indirect evidence that a single neuron of the locus coeruleus may send collateral branches widely ramified into cerebellum and cerebrum ( Olson and Fuxe, 1971; Hoffer et al., 1973 ). Thus one nerve cell of the locus coeruleus can influence very wide-ranging areas of the brain. View chapter Purchase book.
How long does it take for a LC nucleus to develop?
9 In humans LC nucleus is present during 9–12 weeks of gestation with efferent fibers projecting to the neocortex. 9,16 Based on the morphologic evidence of the presence of LC nerve endings in the neocortex, it has been suggested that NA is involved in the development of the neocortex. 17 Axons with NA are first located in the lower part of the cortical marginal zone, which is the site where the tangential axons of Cajal-Retzius cells extend and give their numerous collaterals. Cajal-Retzius cells, the principal cells of the marginal zone, provide signals for the migration of cells born later in development and for lamination during neocortical development. 18,19 It has been proposed that Cajal-Retzius neurons are the targets of the early NA input, 20 since removal of the NA system after birth resulted in an altered number of Cajal-Retzius cells, revealing a more direct role for NA in development and regulation of neuronal migration and laminar formation in the cerebral cortex. 21
What is the limbic system?
Although not empirically proven, the limbic system is a functional concept which may be employed to explain various brain functions .[1]
Which lobe is located at the inferomedial aspect of the cerebral hemispheres?
The limbic lobe situated at the inferomedial aspect of the cerebral hemispheres, consists of two concentric gyri surrounding the corpus callosum. Broca proposed that the larger outer gyrus be named “limbic gyrus” and the smaller inner one “the intralimbic gyrus”. The limbic gyrus (limbic lobe) consists of the isthmus of the cingulate gyrus, the parahippocampal gyrus (both of which are continuous via a bundle of white matter called “cingulum”) and the subcallosal area.[6]
What are the components of the subicular complex?
The subicular complex has three components: the presubiculum, the parasubiculum and subiculum. Subiculum is the transitional zone between the six-layered, entorhinal cortex and the three-layered hippocampus.[5]
Which gyrus is associated with the corpus callosum?
The cingulate gyrus (Latin = Belt ridge) dorsal to the corpus callosum is heavily interconnected with the association areas of the cerebral cortex. The parahippocampal gyrus in the medial temporal lobe contains several distinct regions, the most important being the entorhinal cortex (ERC). The ERC funnels highly processed cortical information to the hippocampal formation and serves as its major output pathway.[5]
Which lobe of the brain is responsible for emotion?
Paul Pierre Broca in 1878 spoke of ‘le grand lobe limbique’or the great limbic lobe and applied the term “limbic” (from the Latin limbusfor border) to the curved rim of the cortex which incudes the cingulate and the parahippocampal gyri. However, its putative role in emotion was elaborated by the American physician, James Papez in 1937 in the seminal paper titled ‘A proposed mechanism of emotion’. This anatomical model is referred to as the Papez circuit.[2] Yakovlev in 1948 proposed Yakovlev's circuit in the control of emotion involving the orbitofrontal, insular and anterior temporal lobe cortex, the amygdala and the dorsomedial nucleus of thalamus.[3] In 1952, Paul D. MacLean coined the term “limbic system” to describe Broca's limbic lobe and related subcortical nuclei as the collective neural substrate for emotion.[1] MacLean was also instrumental in proposing and defining the Triune concept of the brain. MacLean's evolutionary “Triune brain theory” proposed that the human brain was in reality three brains in one: the R-complex (reptilian complex), the limbic system and the neocortex.[4] The concept of the limbic system has since been further expanded and developed by Nauta, Heimer and others.
What are the three zones of the hypothalamus?
It is subdivided from anterior to posterior into three zones: the supraoptic region, the tuberal region and the mammillary region. The three zones are divided on each side into medial and lateral areas by the fornix. The hypothalamic nuclei include the following [Table 1].[5]
How many zones are there in the hippocampal lobe?
Hippocampal formation in the temporal lobe has three distinct zones:
What is the locus coeruleus?
The locus coeruleus (LC), also known as the locus cerulean or locus caeruleus, is a nucleus composed mainly of noradrenergic neurons found in the pons of the brainstem. This center of is one of the parts belonging to the reticular activation system and its main functions are those related to physiological responses to stress and fear.
LC anatomy and connections
The specific location of the locus coeruleus is in the posterior area of the pons of the brainstem, more specifically in the lateral part of the fourth ventricle of the brain.
What functions does this brain region perform?
Due to the increased production of norepinephrine, the main functions of the nucleus coeruleus are those related to the effects that the sympathetic nervous system exerts on stress and fear responses.
Pathophysiology of this nucleus: associated disorders
The abnormal or pathological functioning of the locus coeruleus has been associated with a large number of mental disorders and disorders such as clinical depression, panic disorder, anxiety, and Parkinson's and Alzheimer's diseases.
How many neurons are in the locus coeruleus?
In an adult human, a healthy locus coeruleus can be made up of between 22.00 and 51.000 pigmented neurons of which it can vary in size to the point that the larger ones double in volume to the rest.
Why is the locus coeruleus important?
Due to the aging of the person or certain diseases, the locus coeruleus can suffer important losses in terms of the neuronal population, which contributes to the cognitive deterioration of the person and the appearance of a whole series of neurological disorders .
What functions does this brain region play?
In addition, recent research also points to the possibility that this brainstem center is of vital importance in the proper functioning of the vigil processes .
What are the disorders of the locus coeruleus?
The abnormal or pathological functioning of the locus coeruleus has been associated with a large number of disorders and mental disorders such as clinical depression, panic disorder, anxiety and Parkinson's and Alzheimer's diseases.
Which system is involved in the neural axis?
The connections and corresponding circuits between the locus coeruleus and the neocortex, the diencephalon, the limbic system and the spinal cord make its importance relevant to the functioning of the neural axis.
Which body system receives afferent fibers from the hypothalamus?
In addition, due to its important function as a homeostatic control center in the body, the LC also receives afferent fibers from the hypothalamus . Likewise, the cingulate gyrus and amygdala also innervate the locus coeruleus, allowing distress and emotional pain, and stimuli or stressors to trigger noradrenergic responses.
Who discovered the nervous system?
This center of the nervous system was discovered in the year 1784 by the French physician and anatomist Felix Vicq-d'Azyr, and later the German psychiatrist Christian Reil, redefined it in a more specific and specific way. However, it was not until 1812 that he received the name that remains to this day, which was granted to him by Brother Joseph Wenzel and Karl Wenzel.
What is the limbic lobe?
Broca subdivided his grand lobe limbique into inner (the hippocampus) and outer (the cingulate and parahippocampal gyri) rings. During the last decades of the nineteenth century and the first decades of the twentieth century, it was generally believed that most if not all structures of Broca’s limbic lobe were dominated by olfactory input and therefore form part of the rhinencephalon. In 1937, James Papez proposed that these structures are involved in a closed circuit. The circuit of Papez includes projections from the hippocampus via the fornix to the mamillary body and then via the mamillothalamic tract of Vicq d’Azyr to the anterior thalamic nucleus, from here to the cingulate gyrus, and as last step from the cingulate gyrus back to the hippocampus. Papez suggested that his circuit formed the anatomical basis for emotions. In 1952, Paul MacLean included the circuit of Papez with the amygdala and the hypothalamus into his limbic system, supposed to be responsible for emotional behaviour (the “visceral” or “emotional” brain). Lennart Heimer promoted an expanded version of the classic limbic lobe of Broca, which contains all non-isocortical parts of the cerebral hemisphere together with the laterobasal-cortical amygdaloid complex, with several output channels in the basal forebrain. Thus defined, the limbic lobe contains all of the major cortical and amygdaloid structures known to be especially important for emotional and behavioural functions. Experimental studies in the early 1970s identified the output channels of the limbic lobe in the basal forebrain as the ventral striatopallidal system, the extended amygdala and the basal nucleus of Meynert.
Which lobe of the brain is located in the basal forebrain?
of the limbic lobe in the basal forebrain. These include
Which brain system is responsible for emotions?
In 1952, Paul MacLean included the circuit of Papez with the amygdala and the hypothalamus into his limbic system, supposed to be responsible for emotional behaviour (the “visceral” or “emotional” brain).
Overview
The locus coeruleus (LC), also spelled locus caeruleus or locus ceruleus, is a nucleus in the pons of the brainstem involved with physiological responses to stress and panic. It is a part of the reticular activating system.
The locus coeruleus, which in Latin means "blue spot", is the principal site for brain synthesis of norepinephrine (noradrenaline). The locus coeruleus and the areas of the body affected by the n…
Anatomy
The locus coeruleus (LC) is located in the posterior area of the rostral pons in the lateral floor of the fourth ventricle. It is composed of mostly medium-size neurons. Melanin granules inside the neurons of the LC contribute to its blue colour. Thus, it is also known as the nucleus pigmentosus pontis, meaning "heavily pigmented nucleus of the pons." The neuromelanin is formed by the polymerization of norepinephrine and is analogous to the black dopamine-based neuromelanin i…
Connections
The projections of this nucleus reach far and wide. For example, they innervate the spinal cord, the brain stem, cerebellum, hypothalamus, the thalamic relay nuclei, the amygdala, the basal telencephalon, and the cortex. The norepinephrine from the LC has an excitatory effect on most of the brain, mediating arousal and priming the brain's neurons to be activated by stimuli.
As an important homeostatic control center of the body, the locus coeruleus receives afferents fro…
Function
It is related to many functions via its widespread projections. The LC-NA system modulates cortical, subcortical, cerebellar, brainstem, and spinal cord circuits. Some of the most important functions influenced by this system are:
• Arousal and sleep-wake cycle
• Attention and memory
Pathophysiology
The locus coeruleus may figure in clinical depression, panic disorder, Parkinson's disease, Alzheimer's disease and anxiety. Some medications including norepinephrine reuptake inhibitors (reboxetine, atomoxetine), serotonin-norepinephrine reuptake inhibitors (venlafaxine, duloxetine), and norepinephrine-dopamine reuptake inhibitors (bupropion) are believed to show efficacy by acting upon neurons in this area.
History
The locus coeruleus was discovered in 1784 by Félix Vicq-d'Azyr, redescribed later by Johann Christian Reil in 1809 and named by the brothers Joseph and Karl Wenzel in 1812. High monoamine oxidase activity in the rodent LC was found in 1959, monoamines were found in 1964 and the widespread projections of noradrenergic neurons in the 1970s. An important advance in understanding the anatomical organization of the locus coeruleus was the application of the Fal…
See also
• Reticular formation
External links
• "A Lecture, Higher Brain Function: Activation of the Brain and Levels of Consciousness" at East Tennessee State University
• Stained brain slice images which include the "locus coeruleus" at the BrainMaps project
• Diagram at University of Texas at Austin