Limbic system


Refers to the part of the brain consisting of a rim of cortical tissue around the hilum of the cerebral hemisphere and a group of associated deep brain structure, the amygdala the hippocampus, and septal nuclei.

Limbic cortex oldest part of the cerebral cortex.

Made up of allocortex with three layers of cortical tissue sounding the hilum of the hemisphere.

Between the allocortex and the neocortex is a second ring of transitional cortex, the juxtallocortex.

Refers to a set of brain structures located on both sides of the thalamus, immediately beneath the cerebrum.

It is a collection of structures from the telencephalon, diencephalon, and mesencephalon.

The limbic system includes the olfactory bulbs, hippocampus, hypothalamus, amygdala, anterior thalamic nuclei, fornix, columns of fornix, mammillary body, septum pellucidum, habenular commissure, cingulate gyrus, parahippocampal gyrus, entorhinal cortex, and limbic midbrain areas.

It is associated with a variety of functions including emotion, behavior, motivation, long-term memory, and olfaction.

Emotions largely housed in the limbic system.

Limbic system is associated with the formation of memories.

Defined as a series of cortical structures surrounding the limit between the cerebral hemispheres and the brainstem, that is the border, or limbus, of the brain.

Currently it is considered as one of the many parts of the brain that regulate visceral, autonomic processes.

The following structures are part of the limbic system:

Cortical areas:

Limbic lobe

Orbitofrontal cortex, a region in the frontal lobe involved in the process of decision-making

Piriform cortex, part of the olfactory system

Entorhinal cortex, related with memory and associative components

Hippocampus and associated structures, which play a central role in the consolidation of new memories

Fornix, a white matter structure connecting the hippocampus with other brain structures, particularly the mammillary bodies and septal nuclei.

Subcortical areas:

Septal nuclei, considered a pleasure zone.

Amygdala, located deep within the temporal lobes and related with a number of emotional processes.

Nucleus accumbens: involved in reward, pleasure, and addiction.

Diencephalic structures:

Hypothalamus: a center for the limbic system, connected with the frontal lobes, septal nuclei and the brain stem reticular formation via the medial forebrain bundle, with the hippocampus via the fornix, and with the thalamus via the mammillothalamic fasciculus.

It regulates a great number of autonomic processes.

Mammillary bodies, part of the hypothalamus that receives signals from the hippocampus via the fornix and projects them to the thalamus.

The anterior nuclei of thalamus receive input from the mammillary bodies, and is involved in memory processing.

The limbic system is involved in motivation, emotion, learning, and memory.

It is where the subcortical structures meet the cerebral cortex.

It operates by influencing the endocrine system and the autonomic nervous system.

It is interconnected with the nucleus accumbens, which plays a role in sexual arousal.

It is associated with responses to recreational drugs.

It includes the basal ganglia.

It is tightly connected to the prefrontal cortex, which may be related to the pleasure obtained from solving problems.

This connection can be surgically severed, a prefrontal lobotomy, to change emotional behavior.

It is referred to as a cerebral structure, linked to olfaction, emotions, drives, autonomic regulation, memory, and pathologically to encephalopathy, epilepsy, psychotic symptoms, cognitive defects, sensory processing, time perception, attention, consciousness, instincts, vegetative control, actions and and motor behavior.

Associated disorders are epilepsy and schizophrenia.

The hippocampus is involved with various processes relating to cognition.

Spatial memory was found to have many sub-regions in the hippocampus.

The dorsal hippocampus is an important component for the generation of new neurons, called adult-born granules in adolescence and adulthood.

These new neurons contribute to pattern separation in spatial memory, and causing stronger memory formations.

The left hippocampus is a particularly involved in the recall of spatial memories.

The hippocampus affects learning as new neurons and neural circuits in the hippocampus as a result of the training, causing an overall improvement in the learning of the task.

Damage to the hippocampal region effects on overall cognitive functioning, particularly memory such as spatial memory.

Spatial memory is a cognitive function greatly involved with the hippocampus.

Impairment of the hippocampus can occur from prolonged exposure to stress hormones such as corticocorticoids, and impair explicit memory.

The amygdala is involved in many cognitive and memory processes.

Amygdaloid are episodic-autobiographical memory and not spatial memory as in the hippocampus.

The amygdala’s main function is to note events of a specific emotional significance that can be successfully searched and re-activated.

The amygdala is involved in attentional and emotional processes.

Attention is the ability to home in on some stimuli while ignoring others, and the amygdala seems to be an important structure in this ability.

The ventral hippocampus is especially involved in emotional processes.

Adult-born granule cells (GC) are a part of neurogenesis and the strengthening of spatial memory and learning in the hippocampus and are an essential component in the amygdala.

A deficit of adult-born granule cells results in low emotional functioning, leading to high retention rate of mental diseases, such as anxiety disorders.

The evaluation of faces in social processing, is an area of cognition specific to the amygdala.

The amygdala is involved in determining the trustworthiness of another individual by evaluation of their face

Damage to the structures of limbic system results in conditions like Alzheimer’s disease, anterograde amnesia and retrograde amnesia.

Hippocampus damage causes severe cognitive deficits.

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