Clinical Neuroanatomy and Neurophysiology PDF

CLINICAL NEUROANATOMY AND NEUROPHYSIOLOGY NUCLEI BASALES 6. LESSON Seda GÖZENER PT. MSc.  Nuclei basales are masses of gray matter formed by the group of neurons within the substantia alba of the hemispherium cerebri. They are hided in the substantia alba e...

CLINICAL NEUROANATOMY AND NEUROPHYSIOLOGY NUCLEI BASALES 6. LESSON Seda GÖZENER PT. MSc.  Nuclei basales are masses of gray matter formed by the group of neurons within the substantia alba of the hemispherium cerebri. They are hided in the substantia alba encephali, so they cannot be seen without cerebral sectioning. It is also called subcortical nuclei of telencephalon. They play a role in the coordination of motor movements, initiation of voluntary movements, and posture control associated with voluntary movements.  3 fundamental tasks of basal ganglia Control of complex motor activity (writing, scissors cutting, doing complex sports...) Control of sequential motor movements, integration of information in memory with that instant information Control of the speed and magnitude of movements (adjustment of the number of steps and distances while walking...)  Nucleus caudatus Nucleus lentiformis (putamen and globus pallidus ) They create nuclei basales. Corpus amygdaloideum Claustrum  Nucleus caudatus: The largest of the basal ganglia. It is divided into sections as caput, corpus and cauda. Together with Putamen, it creates a functional unit called neostriatum. The afferents and efferents of nucleus caudatus and putamen are the same. Afferents: cortex cerebri, thalamus, substantia nigra, corpus amygdaloideum. Efferent: globus pallidus, substantia nigra Venriculus is located below the lateralis above the thalamus.  Nucleus lentiformis: Located on the outer side of the nucleus caudatus and thalamus. The outer part is putamen and the inner part is called globus pallidus. The outer face of putamen is separated from the claustrum by capsula externa. The globus pallidus was separated from the nucleus caudatus with the crus anterius capsula internae in the front and from the thalamus with the crus posterius capsula internae in the back. Afferents: neostriatum, nucleus subthalamicus, substantia nigra Efferents: thalamus, nucleus subthalamicus  Corpus amygdaloideum: Located at the front end of the cornu temporale of the ventriculus lateralis. It is in the shape and size of almonds. It is adjacent to the Hippocampus.  It has the greatest role in the formation and processing of emotions within the limbic system. The new external stimulus reaches the corpus amygdaloideum and hippocampus right after the primary sensory cortex. Corpus amygdaloideum associates the stimulus with positive and negative emotions brought from memory. Corpus amygdaloideum is a means of emotional evaluation and expression for what one experiences.  Fasciculus uncinatus connects with the frontal lobe, so rational thought is associated with emotional processes. It provides a direct connection to the limbic system with olfactory sensations from the bulbus olfactorius.  Claustrum: It is beneath the insula cortex. It is separated from cortex cerebri by capsula extrema, separated from putamen by capsula externa. It is connected to many cortical centers such as vision and hearing.  Descending pathways starting from cortex cerebri are included in the pyramidal system, while those working under the influence of basal ganglia are included in the extrapyramidal system.  Nucleus subthalamicus: It is located on the dorsolateral of the upper end of the subtantia nigra. When it is damaged the contralateral hemiballismus (involuntary, severe shaking and jumping movements of the muscles) may occur. Afferents: globus pallidus Efferents: globus pallidus, substantia nigra  Substantia nigra: The largest core of mesencephalon. It is dark coloured because it contains melanin pigment. The lesion in here causes Parkinson's disease. Afferent: neostriatum Efferents: neostriatum, thalamus, colliculus superior  Cortex cerebri and basal ganglia have extensive communication networks. In this way, it is possible for the basal ganglia to intervene in the truncus encephali and medulla spinalis structures where there is no direct relationship.