Caudate Nucleus

Ashley Davidoff MD

Definition

The caudate nucleus is a collection of neurons located within the basal ganglia, near the thalamus.

Structurally the body of the caudate nucleus forms the floor for the lateral ventricles. The region is innervated with dopamine neurons. With the putamen, the caudate nucleus forms the striatum. It is closely associated with the amygdala.

The caudate nucleus is primarily concerned with cognition. It functions in learning, language control, regulation of the cerebral cortex threshold, and affection for loved ones.

Obsessive compulsive disorder can result from caudate nucleus dysfunction and disease. Atrophy of the caudate nucleus contributes to Huntington’s disease. Strokes in the frontal region of the caudate nucleus have been associated with resultant depression. Infarcts in the caudate nucleus lead to apathy and reduced interest in environmental stimuli.

Diagnosis is primarily through clinical observation, followed by neuroimaging techniques.

Treatment may include medical therapy.

The Caudate Nucleus (deep orange)

Part of the Forebrain (Prosencephalon)

Member of the Cerebrum (Telencephalon)

Member of the Basal Ganglia Family

The basic and simplest classification of the brain into forebrain midbrain and hindbrain is shown in this diagram and advanced to a more complex tree using the embryological and evolutionary terminologies. The forebrain consists of the cerebrum also called the prosencephalon, which contains the more advanced form of the brain and the thalamic structures which contain more basic structures. The cerebrum (telencephalon) itself consists of two cerebral hemispheres and paired basal ganglial structures. Each cerebral hemisphere will have gray and white matter distributed in the frontal parietal temporal and occipital lobe, with the basal ganglia being part of the gray matter deep in the cerebral hemispheres. The most important thalamic structures arising from the diencephalons include the thalamus itself and the hypothalamus. The midbrain (mesencepaholon) consists of the tectum tegmentum and cerebral peduncles. The hindbrain has two major branch points based on the evolutionary development. The pons and cerebellum(part of the metencephalon) are grouped and the medulla (part of the myelencephalon is the second branch.

Caudate Nucleus – Forebrain Structure

Part of the Structures that Abut the Ventricular System

The orange c shaped ring lies lateral and to some extent inferior to the lateral ventricles typified by the light blue ring and consists of the thalamus and basal ganglia including the globus pallidus, putamen, head of the caudate nucleus, tail of the caudate nucleus and the amydala. This diagram infers the concept of recurring inverted C shaped structures that are layered both from deep to superficial but also to some extent medial to lateral.

The Basal Ganglia of the Forebrain in Sagittal Projection

Body and Tail of the Caudate

The basal ganglia lie both in the forebrain and in the midbrain. In the forebrain they are distributed in paraventricular fashion almost in an inverted C fashion. In the conceptual diagrams we have colored the inverted “C” that abuts the ventricular system orange, and this includes the thalamus and the basal ganglia. The basal ganglia that lie in the forebrain include the globus pallidus, putamen, head of the caudate nucleus, tail of the caudate nucleus and the amygdala. The amygdala appears to be part of the limbic system and the basal ganglia.

The Caudate Nucleus

The Caudate nucleus lies just behind the the frontal horns of the ventricles, and represented in this instance by orange sausage shaped structures.

The Caudate Nucleus in the Context of the Other Basal Ganglia

Axial Projection

The basal ganglia in the forebrain in the axial projection are seen as a continuous inverted C as well. In this diagram their relationship to the ventricles distributed in paraventricular fashion is exemplified. In the conceptual diagrams we have colored the inverted “C” that abuts the ventricular system orange, and this includes the putamen, globus pallidus, head of the caudate nucleus, tail of the caudate nucleus and the amygdala. The amygdala appears to be part of the limbic system and the basal ganglia.

The Caudate Nucleus in Transverse Section

Anatomic Specimen

The anatomic section is an axial slice through the brain showing the ventricles in midline followed by the genu of the corpus callosum anteriorly and splenium posteriorly, the caudate nucleus, the anterior nucleus, putamen and then surrounded by white matter followed by the gray matter

Courtesy Courtesy Department of Anatomy and Neurobiology at Boston University School of Medicine Dr. Jennifer Luebke, and Dr. Douglas 97135c.8

Caudate Nucleus in Cross Section

T2 Weighted MRI

The axial T2 weighted MRI is taken through the level of the ventricles. It demonstrates the midline ventricuar system, the and the orange ring of paraventricuar basal gaglia including tye caudate nuclii (most anterior and medial) the and the putaen. It also demonstrates putamen which is a pink slmomn in color lying lateral to the white matter. The thalami ar noted posteriorly. The body of the corpus callosum is

Coronal Section

This coronal section through the forebrain reveals the more superficial cortical structures that include the frontoparietal region and the temporal pole(TP). Centrally the corpus callosum (CC) and septum pellucidum SP are noted, and are surrounded by the next paracentral structures which include the left and right lateral ventricles (LV). The basal ganglia starting with the head of the caudate nucleus (Cau) and then the putamen (Put) follow, and these basal ganglia are separated by the internal capsule (IC). The external capsule (XC) and claustrum (Cl) follow as the two lateral structures till we return to the outer umbrella of the frontoparietal cortex again.

Courtesy Department of Anatomy and Neurobiology at Boston University School of Medicine Dr. Jennifer Luebke, and Dr. Douglas Rosene 97342.C3.8L01

CT scan – Head of the Caudate Nucleus

The axial view of the brain using CT shows the oval shaped caudate nuclii lying anteriorly in the brain and posterolateral to the frontal horns

Courtesy Ashley Davidoff MD 38484c01

Anatomic Specimen

Coronal Section

Courtesy Department of Anatomy and Neurobiology at Boston University School of Medicine Dr. Jennifer Luebke, and Dr. Douglas Rosene 97342.C3.8L01

T2 weighted Image of the Caudate Nuclii

The axial view of the brain using T2 Weighted MRI shows the oval or almond shaped head of the caudate nuclii (orange overlay) lying alongside the frontal horns of the lateral ventricles. They are part of the dorsal striatumand are involved in learning, language control.

Tail of the Caudate Nucleus

The axial view of the brain using CT shows the linear tail shaped body of the caudate nuclii (orange overlay) lying alongside the midportions of the lateral ventricles.

Caudate Nucleus on Various Sequences using MRI

The MRI sequences used are displayed in the following chart at the level of the lateral ventricles. The CSF is bright on the average diffusion images, the T2 weighted image, the STIR and the GRE sequence. The best differentiation of gray white matter is on the STIR sequences, while the basal ganglia are best seen on the STIR and GRE sequences Acute infarcts are best seen on the DWI images, enhancing tumors on the T1 with gadolinium and iron deposition of subacute or chronic hemorrhage best characterised on the GRE sequences. FLAIR sequences are sensitive to water in lesions and best characterize MS plaques

Structural and Functional relationships of the Caudate Nucleus

The coronal T1 weighted image reveals the structures that are functionally related to basal ganglial function. These include the caudate nucleus, globus pallidus, putamen, substantia nigra and subthalamus. The caudate nucleus and the putamen are the doorway to the basal ganglia and they receive input from both the sensory cortex and motor cortex. They distribute the signals to the globus pallidus substantia nigra and subthalamic nuclii. The latter (two subthalamic nuclii and substantia nigra) process the signal and send the result back to the globus pallidus which in turn sends the signal back to the thalamus.

Integrated Function of the Basal Ganglia and Thalamus

A simplified drawing of the connections between the caudate nucleus (orange c), the sensory cortex (salmon pink) and the basal ganglia is shown. After the stimulus has reached the sensory cortex for quantification and qualification it connects to the basal ganglia through the caudate nucleus and putamen. Each of these connects with the two parts of the globus pallidus (gp) which feed back to the thalamus. The caudate nucleus also feeds back and forth to the substantia nigra (sni) and the subthalamic nucleus (stn) brain basal ganglia connections functional thalamus sensory cortex putamen= p caudate nucleus = cn globus pallidus = gp substantia nigra = sni subthalamic nucleus = snu

Applied Biology

Acute Hemorrhagic Infarct

Mass Effect on the Lateral Ventricle and Caudate Nucleus

The brain has a characteristic appearance characterised by its creamy color and characteristic shape and fissured surface. This pathological specimen shows an acute hemorrhagic infarct in the left frontoparietal region with necrosis of the brain tissue and mass effect on the lateral ventricle and midline shift. The specimen also serves to reveal the normal right side with its creamy color and darker brownish gray matter that is accentuated by increasing the contrast on the right image (b). Other structures that are seen include the corpus callosum that lies above the ventricles (cc), the caudate nucleus (c) that lies inferior to the lateral ventricle, the line of white matter between the caudate and putamen called the internal capsule, the 3rd ventricle (3) medial to these structures , and the thalamus (th) inferior to them. The interhemispheric fissure (if) is seen superiorly and the Sylvian fissure (Sf) is seen laterally. The horizontal folds and darker color of the cerebellum are characteristics of that structure.

Bilateral Lacunes

The axial CT scan shows bilateral low density lesions in the caudate nuclii with the left slightly larger than the right, consistent with chronic bilateral lacunar infarcts. A lacune is also seen in the right putamen.

Courtesy Ashley Davidoff MD 71562 71561