Pale globe: structure, functions and associated disorders

Although they are not as well known to most people as the brain lobes, subcortical regions of the brain they perform equally important functions. Specifically, the areas we know as the basal ganglia are essential for movement, among others.

One of the nuclei that form the basal ganglia is the pale globe, the smallest of all. Below we will see the structure and functions of the pale globe, As well as injury-related disorders in this region, including Parkinson’s disease.

What is a pale balloon?

The pale globe is also known as the paleostriad. It is a subcortical structure made up of gray matter (i.e., sums of neurons, dendrites without myelin, and glial cells) that develops from the diencephalon, although it does part of the telencephalon. It is therefore located in the anterior part of the brain, on the internal face of the frontal lobe.

It is part of the extrapyramidal system, A neural network that controls and regulates involuntary movements. The extrapyramidal tracts send projections primarily to the lower motor neurons in the spinal cord which process movement, reflexes, and posture.

this structure it is more developed in primates than in other animals; in particular, the inner region of the pale globe is only found in humans and our closest relatives.

    The basal ganglia

    The pale is one of the structures that make up the basal ganglia, a collection of tightly related subcortical nuclei located around the third ventricle. The basal ganglia perform functions mainly related to voluntary and automatic movements.

    The nuclei that form the basal ganglia, In addition to the pale globe, they are:

    • Corpus striatum: receives information from other basal ganglia, integrates it and sends it to higher areas of the brain.
    • caudate nuclei: Has frontal lobe connections and is involved in motivation and alarm response.
    • Black substance: relevant for fine motor control; it is part of the brain reward system because it has many dopaminergic synapses.
    • Nucleus accumbens: like dark matter, it is part of the reinforcement system, so it plays a key role in the development of addictions.
    • Putamen: This structure is involved in automated movements, especially those of the face and limbs.
    • Subhalamic nucleus: Connects the midbrain and the thalamus and regulates motor skills.
    • red substance: This region is important for coordination in general and that of the upper limbs in particular.

    Structure and anatomy

    The pale globe is composed mainly of very large neurons and with a large number of dendritic branches. The appearance of the pale globe is peculiar due to the abundance of dendrites and their unusual length.

    The name of this structure is due to the fact that it is crossed by numerous myelinated axons that connect other regions of the basal ganglia to the pale globe, giving it the characteristic whitish tone of areas of the brain with high density of white matter.

    The pale globe is generally divided into two parts: internal or medial and external or laterall. The inner pale balloon receives efferents from the corpus striatum and projects afferents to the thalamus, which sends them to the prefrontal cortex. The outer part contains gabaergic neurons and acts in conjunction with the subthalamic nucleus.

    Functions of the pale globe

    The main function of the pale globe is the regulation of unconscious movements. In this sense, its role is to modulate the excitatory impulses of the cerebellum by synchronizing the neurotransmitter GABA, the most relevant inhibitory compound of the nervous system.

    The joint action of the cerebellum and the pale allows the maintain posture and perform harmonious movements. If the pale balloon is not functioning properly, there is impaired gait, manual motor skills, and many other common behaviors.

    This role is mainly due to the internal pale globe and its connections to higher brain structures. This region of the pale recibe afferents of the striate body from the basal ganglia and sends them to the thalamus, which regulates basic bodily functions such as alertness and sleep and allows sensory and motor information to reach the cortex.

    The lateral part of the pale, in conjunction with the subthalamic nucleus, participates in regulation of physiological rhythms of the organism, especially compared to the rest of the structures of the basal ganglia.

    related disorders

    Pale balloon injuries cause motor disturbances because they disrupt the connections of the extrapyramidal pathways. Thus, the assignment of this structure can cause symptoms such as tremors, spasms, bradykinesia (Slowness of movement), stiffness, dystonia (uncontrollable contractions), convulsions or ataxia (lack of muscle coordination).

    The disorder most clearly associated with pale globe lesions is Parkinson’s disease, which causes degeneration of subcortical structures, including the basal ganglia.

    Some typical symptoms of Parkinson’s disease, Such as tremors at rest, muscle stiffness and postural problems, are explained by damage to the pallor and / or the cerebellum. However, as this disease progresses, it also causes lesions in other parts of the brain; this is the cause of the progressive cognitive impairment observed in these patients.

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