limbic system

(noun)

A set of brain structures located on both sides of the thalamus, right under the cerebrum. Supports a variety of functions including emotion, behavior, motivation, long-term memory, and olfaction.

Related Terms

Examples of limbic system in the following topics:

  • Limbic System

    • The limbic system makes up the inner border of the cortex and is vital for emotion, motivation, and memory.
    • The term "limbic" comes from the Latin limbus, for "border" or "edge," because the limbic system forms the inner border of the cortex.
    • The limbic system operates by influencing the endocrine system and the autonomic nervous system.
    • The limbic system is also tightly connected to the prefrontal cortex.
    • This diagram of the limbic system delineates components of the diencephalon and cerebrum.

  • Epithalamus and Pineal Gland

    • The epithalamus connects the limbic system to other parts of the brain.
    • The epithalamus acts as a connection between the limbic system and other parts of the brain.
    • It is wired with the limbic system and basal ganglia.

  • Control of Autonomic Nervous System Function

    • The medulla oblongata, in the lower half of the brainstem, is the control center of the autonomic nervous system.
    • The autonomic nervous system (ANS) is the part of the peripheral nervous system which acts to control involuntary functions which are critical for survival.
    • The hypothalamus acts to integrate autonomic functions and receives autonomic regulatory feedback from the limbic system to do so.
    • The sympathetic division of the ANS is often referred to as the sympathetic nervous system (SNS).
    • The medulla is a subregion of the brainstem and is a major control center for the autonomic nervous system.

  • Autonomic Reflexes

    • The autonomic nervous system (ANS or visceral nervous system or involuntary nervous system) is the part of the peripheral nervous system that acts as a control system.
    • The hypothalamus, just above the brain stem, acts as an integrator for autonomic functions, receiving ANS regulatory input from the limbic system to do so.
    • The ANS is classically divided into two subsystems: the parasympathetic nervous system (PSNS) and sympathetic nervous system (SNS) which operate independently in some functions and interact co-operatively in others.
    • A more modern characterization used is that the sympathetic nervous system is a "quick response mobilising system" and the parasympathetic is a "more slowly activated dampening system"; but even this also has exceptions, such as in sexual arousal and orgasm where both play a role.
    • The enteric nervous system is also sometimes considered part of the autonomic nervous system, and sometimes considered an independent system.

  • Aging and the Nervous System

    • One of the effects of aging on the nervous system is the loss of neurons in cerebral cortex.
    • One of the effects of aging on the nervous system is the loss of neurons.
    • Parkinson's disease is the most common movement disorder of the nervous system.
    • As the disorder progresses, cognitive (intellectual) impairment extends to the domains of language (aphasia), skilled movements (apraxia), recognition (agnosia), and those functions (such as decision-making and planning) closely related to the frontal and temporal lobes of the brain as they become disconnected from the limbic system, reflecting extension of the underlying pathological process.

  • Functions of the Diencephalon

    • Distinct parts of diencephalon perform numerous vital functions, from regulating wakefulness to controlling the autonomic nervous system.
    • In particular, every sensory system (with the exception of the olfactory system) includes a thalamic nucleus that receives sensory signals and sends them to the associated primary cortical area.
    • The hypothalamus performs numerous vital functions (e.g., regulation of certain metabolic processes), most of which relate directly or indirectly to the regulation of visceral activities by way of other brain regions and the autonomic nervous system.
    • The epithalamus functions as a connection between the limbic system and other parts of the brain.

  • Short-Term Neural Control

    • The autonomic nervous system plays a critical role in the regulation of vascular homeostasis.
    • The baroreceptors in the venae cavae and right atrium monitor blood pressure as the blood returns to the heart from the systemic circulation.
    • These include the limbic system, which links physiological responses to psychological stimuli, chemoreceptor reflexes, generalized sympathetic stimulation, and parasympathetic stimulation.

  • Sensory and Motor Tracts

    • Somatosensory organization is divided into the dorsal column–medial lemniscus tract (the touch/proprioception/vibration sensory pathway) and the anterolateral system, or ALS (the pain/temperature sensory pathway).

  • Hypothalamus

    • The hypothalamus serves as a gateway between the nervous system and endocrine system.
    • One of the most important functions of the hypothalamus is linking the nervous system to the endocrine system via the pituitary gland (hypophysis).
    • These hormones are released into the bloodstream and target other organ systems, most notably the pituitary.
    • The hypothalamus affects the endocrine system and governs emotional behavior such as anger and sexual activity.
    • The hypothalamus is thus richly connected with many parts of the central nervous system, including the brainstem, reticular formation and autonomic zones, and the limbic forebrain (particularly the amygdala, septum, diagonal band of Broca, olfactory bulbs, and cerebral cortex).

  • Neural Mechanisms (Cortex)

    • Additionally, other structures may override voluntary respiratory signals, such as the activity of limbic center structures like the hypothalamus.
    • It also provides parasympathetic stimulation for the heart and the digestive system.