The Papez Circuit in the Limbic System

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.

Cingulate gyrus

gyrus cinguli

The Cingulate gyrus is an important part of the limbic system in the Cerebrum. This strip of Cortex runs medially in the cerebrum, directly above the Corpus callosum Among other things, it is involved in emotions and memory. Through its connections to limbic and autonomic centers, it can also influence autonomic responses (e.g., heart rate, blood pressure). The anterior (front) region in particular is also associated with attention, motivation, error monitoring, and emotion regulation.

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.

Archicortex

An ancient structure of the cerebrum in terms of evolutionary development, which, in contrast to the isocortex (also called the neocortex), has a three-layer structure. The archicortex mainly comprises the hippocampal structures. 

Temporal lobe

Lobus temporalis

The temporal lobe is one of the four lobes of the cerebrum and is located laterally (on the side) at the bottom. It contains important areas such as the auditory cortex and parts of Wernicke's area, as well as areas for higher visual processing; deep within it lies the medial temporal lobe with structures such as the hippocampus.

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."

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.

Ammon's horn

cornu ammonis

Part of the cerebrum, specifically the front end of the hippocampus. The Cornu Ammonis is divided into fields CA1 to CA4. It owes its name to its shape, which resembles the horn of an ammon sheep.

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.

Subiculum

The transition zone between the cornu ammonis and the entorhinal cortex is called the subiculum.

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.

Cingulate gyrus

gyrus cinguli

The cingulate gyrus is an important part of the limbic system in the cerebrum. This strip of cortex runs medially in the cerebrum, directly above the corpus callosum. Among other things, it is involved in emotions and memory. Through its connections to limbic and autonomic centers, it can also influence autonomic responses (e.g., heart rate, blood pressure). The anterior (front) region in particular is also associated with attention, motivation, error monitoring, and emotion regulation.

Cerebrum

telencephalon

The cerebrum comprises the cerebral cortex (gray matter), the nerve fibers (white matter), and the basal ganglia. It is the largest part of the brain. The cortex can be divided into four cortical areas: the temporal lobe, frontal lobe, occipital lobe, and parietal lobe.
Its functions include the coordination of perception, motivation, learning, and thinking.

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 1,800^cm². 

Corpus callosum

As the largest commissure (connection in the brain), the corpus callosum connects the two cerebral hemispheres. It consists of 200-250 million nerve fibers and serves to exchange information.

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.