He Putamen Is a narrowing of the brain that is situated right in the middle region of the brain. Together with the caudate nucleus forms a subcortical region of the forebrain known as a striatum.
On the other hand, the putamen forms another important structure of the Encephalon . Together with the pale balloon, it constitutes the extraventricular nucleus of the striatum or lenticular nucleus.
Thus, putamen is one of the three main Basal ganglia Of the brain, and at the same time, forms two secondary structures through the union with two different nuclei.
At the functional level, it is notable for its participation in the motor control of the body. Specifically, it appears to be especially involved in the execution of specific voluntary movements.
Characteristics of the putamen
The putamen is a brain structure that is located right in the center of the brain. The connection established with the caudate nucleus constitutes the striatum, while its union with the pale globe gives rise to the lenticular nucleus.
Etymologically, the word putamen comes from Latin and refers to something that falls when pruning. Specifically, the term putamen comes from"putare"meaning to prune.
It stands out as one of the main nuclei of the basal ganglia of the brain . These ganglia form a group of masses of gray matter that are located between the ascending and descending pathways of White matter Of the brain.
Thus, the putamen is a small region Telencephalon , The brain's most superior brain structure. This region is mainly responsible for motor control of the body, but recent research has linked it with other types of functions.
It is postulated that the functioning of the putamen in conjunction with the connection established with other nuclei of the striatum could play an important role in processes such as learning or emotional regulation.
Circuit of the putamen
Putamen (orange), Caudate Core (purple)
The putamen circuit is a motorway that belongs to the basal nuclei. It determines a series of connections established by the putamen, which seem to play an especially important role in the execution of learned movements.
In fact, this circuit of the putamen is also known as motor circuit, since it results the neuronal connection system that is responsible for motor programs according to the context.
However, this circuit does not start in the putamen, but in the cerebral cortex . Specifically, it has its onset in the pre-motor, supplemental, primary motor and somato-sensory areas of the cerebral cortex.
These upper structures project glutamatergic nerve fibers to the putamen and thus establish connection with said nucleus of the striatum. This fiber projection is executed through two main channels: the direct path and the indirect path.
The direct path of the circuit ends in the inner, Black substance Reticular. These structures project nerve fibers into the thalamus and return the information to the cortex, thus forming a feedback loop.
In the indirect way, the putamen sends information to the external pale and this structure is responsible for projecting the fibers towards the subthalamic nucleus. Later, the subthalamic nucleus projects towards the inner pale and the black substance reticular. Finally, the information is returned through the thalamus.
Functioning
The putamen is characterized by having a feedback activity with the cerebral cortex. That is, it collects information belonging to these brain structures and then resends it.
However, this connection does not perform directly but projects the nerve fibers to other structures before they reach the motor cortex. In the same way, when the cerebral cortex projects to the putamen, the information passes previously by other encephalic regions.
In this sense, through the direct pathway, the putamen connects with the cerebral cortex through the inner pallid globe, the thalamus and the Black substance Reticular. In the indirect way, it does the same through the subthalamic nucleus, the inner pallid and the black reticular substance.
The two connection paths operate in parallel and oppose each other. That is, activation of the direct pathway reduces the inhibitory function of the inner pallid and the black substance reticular to the thalamus, which becomes uninhibited and sends more excitatory information to the cortex.
By contrast, activation of the indirect pathway increases the activity of the subthalamic nucleus and, therefore, the inhibitory output of the inner pallid and the reticular black substance. In this case, the activity of the thalamus is decreased and less information is sent to the cortex.
Functions
The putamen has three main functions: control of movement, learning by reinforcement and regulation of feelings of love and hate. While the first two activities are highly evidenced, the third is only a hypothesis today.
As far as movement is concerned, the putamen does not constitute a structure specialized in motor functions. However, the close relationship it has with other regions such as the caudate nucleus or accumbens, causes it to participate in this type of activities.
On the other hand, many studies have shown that putamen is a structure that plays an important role in different types of learning. The main ones are reinforcement learning and category learning.
Finally, a recent study by the neurobiology laboratory at the University of London has postulated that the putamen is involved in the regulation and development of feelings of love and hate.
Associated diseases
The putamen seems to be a brain structure involved in a large number of pathologies. Of these, the most associated to its functioning is the Parkinson's disease .
Likewise, other alterations such as the cognitive deterioration originated in the Alzheimer disease , the Huntington's disease , the Dementia by Lewy bodies , the schizophrenia , the depression , he Tourette syndrome or the ADHD May also, in some cases, be associated with the functioning of this brain structure.
References
- Grillner, S; Ekeberg,; The, Manira; Lansner, A; Parker, D; Tegnér, J; Wallén, P (May 1998). "Intrinsic function of a neuronal network - a vertebrate central pattern generator". Brain research. Brain research reviews 26 (2-3): 184-97.
- Griffiths PD; Perry RH; Crossman AR (March 14, 1994). "A detailed anatomical analysis of neurotransmitter receptors in the putamen and caudate in Parkinson's disease and Alzheimer's disease."Neuroscience Letters. 169 (1-2): 68-72.
- Parent, André."The History of the Basal Ganglia: The Contribution of Karl Friedrich Burdach." Neuroscience & Medicine. 03 (04): 374-379.
- Packard MG; Knowlton BJ (2002). "Learning and memory functions of the Basal Ganglia."Ann Rev Neurosci. 25 (1): 563-93.