The Limbic System
The limbic system is marked by an eventful history in neuroscience. For a long time, it was considered the single center of our emotions, a message which has been conveyed by numerous popular science texts. In fact, the function of the limbic system goes far beyond this. In addition to controlling emotions, it also influences memory, motivation and the endocrine system. Conversely, our emotional life is too complex to be explained solely by the rather limited structures of the limbic system.
Scientific support: Prof. Dr. Herbert Schwegler, Prof. Dr. Anne Albrecht
Published: 22.12.2023
Difficulty: intermediate
The term “limbic system” is very vague and refers to a group of structures involved in the processing of emotions and Memory processes. There are different ideas about which structures these are. The most important ones are the hippocampus, amygdala, cingulate gyrus, and parahippocampal gyrus.
emotions
Neuroscientists understand "emotions" to be complex response patterns that include experiential, physiological, and behavioral components. They arise in response to personally relevant or significant events and generate a willingness to act, through which the individual attempts to deal with the situation. Emotions typically occur with subjective experience (feeling), but differ from pure feeling in that they involve conscious or implicit engagement with the environment. Emotions arise in the limbic system, among other places, which is a phylogenetically ancient part of the brain. Psychologist Paul Ekman has defined six cross-cultural basic emotions that are reflected in characteristic facial expressions: joy, anger, fear, surprise, sadness, and disgust.
Memory
Memory is a generic term for all types of information storage in the organism. In addition to pure retention, this also includes the absorption of information, its organization, and retrieval.
Historical misinterpretations
It is not possible to say unequivocally which structures and areas belong to the Limbic system – the information varies depending on the position and concept of the respective author. The oldest definition comes from the French physician Paul Broca (1824–1880). In 1878, he postulated that there was an area in the cerebral Cortex that differed fundamentally from the rest of the cortex – and which Broca mistakenly assumed was exclusively responsible for smell. As this area forms a ring around the thalamus and parts of the basal ganglia, he chose the Latin term “limbus,” which means ‘border’ or “edge.”
In 1949, the US physician and brain researcher Paul McLean formulated the theory that the limbic system is the center of our emotions and thus represents an emotional brain within the brain, much like a biological matryoshka doll. He based his now outdated theory on evolutionary concepts: First, he believed, came the basic survival of the reptilian brain, then the emotional control of the limbic system, and only at the very end did the higher cortical areas develop. None of this is true.
McLean assumed that, in addition to the areas identified by Broca, the Amygdala and the Septum were also involved in the limbic system. At least with regard to the amygdala, McLean's biological classification is still scientifically accepted today.
Limbic system
The limbic system is a functional unit in the brain. It consists of interconnected structures, primarily in the cerebrum and diencephalon. The structures assigned to the system vary depending on the source, but the most important components are the hippocampus, amygdala, cingulate gyrus, septum, and mammillary bodies. The limbic system is involved in autonomic and visceral processes as well as in mechanisms of emotion, memory, and learning. Some authors mistakenly reduce the limbic system to the emotional world by referring to it as the "emotional brain."
Cortex
cortex cerebri
Cortex refers to a collection of neurons, typically in the form of a thin surface. However, it usually refers to the cerebral cortex, the outermost layer of the cerebrum. It is 2.5 mm to 5 mm thick and rich in nerve cells. The cerebral cortex is heavily folded, comparable to a handkerchief in a cup. This creates numerous convolutions (gyri), fissures (fissurae), and sulci. Unfolded, the surface area of the cortex is approximately 1,800cm².
emotions
Neuroscientists understand "emotions" to be complex response patterns that include experiential, physiological, and behavioral components. They arise in response to personally relevant or significant events and generate a willingness to act, through which the individual attempts to deal with the situation. Emotions typically occur with subjective experience (feeling), but differ from pure feeling in that they involve conscious or implicit engagement with the environment. Emotions arise in the limbic system, among other places, which is a phylogenetically ancient part of the brain. Psychologist Paul Ekman has defined six cross-cultural basic emotions that are reflected in characteristic facial expressions: joy, anger, fear, surprise, sadness, and disgust.
Amygdala
corpus amygdaloideum
An important core area in the temporal lobe that is associated with emotions: it evaluates the emotional content of a situation and reacts particularly to threats. In this context, it is also activated by pain stimuli and plays an important role in the emotional evaluation of sensory stimuli. Inaddition, it is involved in linking emotions with memories, emotional learning ability, and social behavior. The amygdala is part of the limbic system.
Septum
area septalis
The septal nuclei are located medially in the basal forebrain, near the anterior tip of the cingulate gyrus. They are connected to the olfactory cortex and linked to other limbic structures via the fornix. Functionally, they play a role in emotional processes and reward processing.
Subareas of the limbic system
Today, most scientists include the hippocampus, the cingulate gyrus, the parahippocampal gyrus, the amygdala, and the corpus mammillare in the Limbic system There is also discussion about extending the limbic system to include the olfactory brain – including the Septum – and parts of the thalamus. At this point, it becomes clear that the limbic system is not defined topographically by the local proximity of structures, but rather by their functional connections.
And indeed, the structures involved are closely linked. Numerous studies suggest that the limbic system controls at least part of our affective behavior and thus influences emotions and sexuality. It also plays a central role in the storage of Memory content and is thus involved in learning processes. Particularly important here is the Papez circuit, named after the US neurologist James Papez, who discovered this circuit in the 1930s.
Limbic system
The limbic system is a functional unit in the brain. It consists of interconnected structures, primarily in the cerebrum and diencephalon. The structures assigned to the system vary depending on the source, but the most important components are the hippocampus, amygdala, cingulate gyrus, septum, and mammillary bodies. The limbic system is involved in autonomic and visceral processes as well as in mechanisms of emotion, memory, and learning. Some authors mistakenly reduce the limbic system to the emotional world by referring to it as the "emotional brain."
Septum
area septalis
The septal nuclei are located medially in the basal forebrain, near the anterior tip of the cingulate gyrus. They are connected to the olfactory cortex and linked to other limbic structures via the fornix. Functionally, they play a role in emotional processes and reward processing.
emotions
Neuroscientists understand "emotions" to be complex response patterns that include experiential, physiological, and behavioral components. They arise in response to personally relevant or significant events and generate a willingness to act, through which the individual attempts to deal with the situation. Emotions typically occur with subjective experience (feeling), but differ from pure feeling in that they involve conscious or implicit engagement with the environment. Emotions arise in the limbic system, among other places, which is a phylogenetically ancient part of the brain. Psychologist Paul Ekman has defined six cross-cultural basic emotions that are reflected in characteristic facial expressions: joy, anger, fear, surprise, sadness, and disgust.
Memory
Memory is a generic term for all types of information storage in the organism. In addition to pure retention, this also includes the absorption of information, its organization, and retrieval.
The Papez circuit
he Papez circuit runs from the Hippocampus via the Fornix to the mammillary bodies and on via the thalamus to the cingulate gyrus, which in turn projects back to the hippocampus. This closes a circuit that is essential for Memory: if it is interrupted by surgery or lesions, patients lose the ability to store new memories. Although they remember their past – the older the memory, the better – the pathway from short-term to Long-term memory is destroyed.
Disorders of the Limbic system are also repeatedly associated with unusual emotions or moods, such as schizophrenia or bipolar disorder, anxiety or aggression disorders, but also depression.
Hippocampus
The hippocampus is the largest part of the archicortex and an area in the temporal lobe. It is also an important part of the limbic system. Functionally, it is involved in memory processes, but also in spatial orientation and learning. It comprises the subiculum, the dentate gyrus, and the Ammon's horn with its four fields CA1-CA4.
Changes in the structure of the hippocampus due to stress are associated with chronic pain. The hippocampus also plays an important role in the amplification of pain through anxiety.
Fornix
The fornix is a nerve pathway consisting of approximately 12 million fibers that connects the hippocampus (one of the oldest structures in the brain in evolutionary terms) and subiculum with the septum and mammillary bodies.
Memory
Memory is a generic term for all types of information storage in the organism. In addition to pure retention, this also includes the absorption of information, its organization, and retrieval.
Long-term memory
Long-term memory stores information about events, facts, or skills over long periods of time, often for a lifetime. Different types of memory are stored in different areas of the brain. The cellular basis for these learning processes is based, among other things, on improved communication between two cells and is called long-term potentiation.
Limbic system
The limbic system is a functional unit in the brain. It consists of interconnected structures, primarily in the cerebrum and diencephalon. The structures assigned to the system vary depending on the source, but the most important components are the hippocampus, amygdala, cingulate gyrus, septum, and mammillary bodies. The limbic system is involved in autonomic and visceral processes as well as in mechanisms of emotion, memory, and learning. Some authors mistakenly reduce the limbic system to the emotional world by referring to it as the "emotional brain."
emotions
Neuroscientists understand "emotions" to be complex response patterns that include experiential, physiological, and behavioral components. They arise in response to personally relevant or significant events and generate a willingness to act, through which the individual attempts to deal with the situation. Emotions typically occur with subjective experience (feeling), but differ from pure feeling in that they involve conscious or implicit engagement with the environment. Emotions arise in the limbic system, among other places, which is a phylogenetically ancient part of the brain. Psychologist Paul Ekman has defined six cross-cultural basic emotions that are reflected in characteristic facial expressions: joy, anger, fear, surprise, sadness, and disgust.
Depression
A mental illness whose main symptoms are sadness and a loss of joy, motivation, and interest. Current classification systems distinguish between different types of depression.
Controversial but significant
The Limbic system consists of a closely networked group of brain areas that send signals to various parts of the cerebrum, but also to the Brain stem Important components are the hippocampus, cingulate gyrus, parahippocampal gyrus, amygdala, and corpus mamillare.
The definition of the limbic system is controversial because it is a historically influenced term whose functions cannot be clearly delineated as was previously assumed. This applies in particular to the processing of emotions, which in isolated cases is still attributed solely to the limbic system today. We now know that although limbic structures play an important role in the processing of emotions, learning, and memory, they are embedded in a much larger networks.
Limbic system
The limbic system is a functional unit in the brain. It consists of interconnected structures, primarily in the cerebrum and diencephalon. The structures assigned to the system vary depending on the source, but the most important components are the hippocampus, amygdala, cingulate gyrus, septum, and mammillary bodies. The limbic system is involved in autonomic and visceral processes as well as in mechanisms of emotion, memory, and learning. Some authors mistakenly reduce the limbic system to the emotional world by referring to it as the "emotional brain."
Brain stem
truncus cerebri
The "trunk" of the brain, to which all other brain structures are "attached," so to speak. From bottom to top, it comprises the medulla oblongata, the pons, and the mesencephalon. It transitions into the spinal cord below. It is a center for vital functions such as breathing and heartbeat and contains ascending and descending pathways between the cerebrum, cerebellum, and spinal cord.
First published on November 14, 2011
Updated on December 22, 2023
