Corpus striatum: structure, functions and associated disorders

The basal ganglia are fundamental structures for the regulation of movement and reward-motivated learning, among other functions. This part of the brain is made up of several nuclei, among which highlight what we call the “striate body”.

In this article we will describe the structure and functions of the corpus striatum. We will also explain its relationship with other regions of the brain and with certain physical and psychological disorders that arise as a result of alterations in the striatum.

    The corpus striata and the basal ganglia

    The striated body also called “striate nucleus” and “neostriate”. It is a set of structures located at the subcortical level which in turn are part of the basal ganglia, involved in the regulation of intentional and automatic movements, as well as in procedural learning, reinforcement and planning. .

    The basal ganglia are located in the forebrain (Or forebrain), under the lateral ventricles. They are formed by the caudate nucleus, putamen, nucleus accumbens, olfactory tubercle, pale globe, substantia nigra, and part of the subthalamus.

    Technically, the term “corpus striata” encompasses most of the basal ganglia, with the exception of the substantia nigra and the subthalamic nucleus, as in the past these structures were conceived as a functionally linked whole; However, thanks to recent research, we have more information about the differences between these areas.

    Today we call the whole “striated” composed of the caudate nucleus, putamen and nucleus accumbens, Which connects the two previous structures. For its part, the concept of “striated body” is mainly used to designate the combination of striated and pale balloon.

      Structure and connections

      The splined body consists of two main sections: the dorsal and ventral striatum. The former consists of the putamen, the pale globe, and the caudate and lenticular nuclei, while the ventral striatum is formed by the nucleus accumbens and the olfactory bulb.

      Most of the neurons that make up the corpus striatum are medium spiny neurons, which get their name from the shape of their dendrites. We can also find Deiter neurons, which have long dendrites with few branches, and interneurons, especially cholinergic and catecholaminergic.

      The caudate and the putamen, which together form the neo-striatum, they receive afferents from the cerebral cortex, Being the most important route by which information reaches the basal ganglia.

      In contrast, the efferents of the basal ganglia mainly originate from the pale globe, which, as we have said, is part of the striated body according to the classical definition, but not the striated as such. From the pale globe, efferent gabaérgicas are sent (And therefore inhibitory) indirectly in the premotor cortex, responsible for voluntary movement.

      Functions of the striatum

      Overall, the basal ganglia perform a wide variety of functions, primarily related to motor skills. These cores contribute to the proper functioning of the following processes:

      • Motor learning.
      • Procedural memory processing.
      • Beginning of voluntary movements.
      • Regulation of voluntary movements: Direction, intensity, amplitude …
      • Execution of automatic movements.
      • Beginning of eye movements.
      • Regulation of working (or operational) memory.
      • Warning.
      • Regulation of motivated behavior (depending on dopamine).
      • Selection of actions according to the expected reward.

      The corpus striatum is related to most of these functions, constituting the most important part of the basal ganglia. Specifically, the ventral striatum average in learning and motivated behavior by secretion of dopamine, while the dorsal section is involved in movement control and executive functions.

      related disorders

      Most disorders and diseases associated with the corpus striatum they affect movements, both voluntary and automatic. Parkinson’s disease and Huntington’s disease are two fundamental examples of basal ganglia dysfunction.

      However, certain psychological alterations seem to be influenced by the functioning of this structure, mainly in relation to its role in the brain reward system.

      1. Parkinson’s disease

      Parkinson’s disease causes brain damage, mainly in the basal ganglia. Death of dopaminergic neurons in substantia nigra, it interferes with the release of dopamine in the striatum, causing motor symptoms such as slowness, stiffness, tremors, and postural instability. More depressive symptoms occur.

      2. Huntington’s disease

      During its initial phase, Huntington’s disease mainly affects the corpus striatum; this explains why the first symptoms are related to motor control, emotions and executive functions. In this case, the basal ganglia are unable to prevent unnecessary movementTherefore, hyperkinesia occurs.

      3. Bipolar disorder

      Research suggests that in some cases of bipolar disorder, there are alterations in the genes that regulate the body’s striated function. Evidence in this regard has been found for bipolar disorder type I and type II.

        4. Obsessive-compulsive disorder and depression

        Obsessive-compulsive disorder and depression, which they have a similar biological basis, Have been associated with striatal dysfunction. This would explain the decrease in mood that occurs in both disorders; in OCD, the difficulty of inhibiting movements is also relevant.

          5. Outbuildings

          Dopamine is a neurotransmitter involved in the brain reward system; the pleasurable sensations we feel when dopamine is released in the basal ganglia are the reason why we seek out experiences that we know are pleasurable. This explains addictions from a physiological point of view.

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