Which ventricle of the brain is found in the diencephalon

The hypothalamus is the executive region in charge of the autonomic nervous system and the endocrine system through its regulation of the anterior pituitary gland. Other parts of the hypothalamus are involved in memory and emotion as part of the limbic system. Two groups of nuclei called the the mammillary bodies are located on the posterior part of the hypothalamus and are important for episodic memory, which is the memory of every day events that you can recollect.

The structure emerges from the ventral surface of the forebrain as a tapering cone that connects the brain to the spinal cord. Attached to the brainstem, but considered a separate region of the adult brain, is the cerebellum. The midbrain coordinates sensory representations of the visual, auditory, and somatosensory perceptual spaces.

The pons is the main connection with the cerebellum. The pons and the medulla regulate several crucial functions, including the cardiovascular and respiratory systems such as heart rhythm or breathing rate. The reticular activating system is found in the midbrain, pons, medulla and part of the thalamus and controls levels of wakefulness, maintains consciousness, enables people to pay attention to their environments, and is involved in sleep patterns and regulating the sleep cycle.

The cranial nerves connect through the brainstem and provide the brain with the sensory input and motor output associated with the head and neck, including most of the special senses.

The major ascending and descending pathways between the spinal cord and brain, specifically the cerebrum, pass through the brainstem. The mesencephalon, one of the original region of the embryonic brain, becomes the midbrain, a small region between the thalamus and pons. The cerebral aqueduct passes through the center of the midbrain, such that these regions are the roof and floor of that canal.

Indeed, the midbrain is separated into the tectum and tegmentum, from the Latin words for roof and floor, respectively. The superior colliculus is the superior pair and combines sensory information about visual space, auditory space, and somatosensory space. The inferior colliculus is the inferior pair of these enlargements and is part of the auditory pathway trochlear nerve, CN IV.

Neurons of the inferior colliculus project to the thalamus, which then sends auditory information to the cerebrum for the conscious perception of sound. The tegmentum is continuous with the gray matter of the rest of the brainstem.

The substantia nigra consists of basal nuclei with a black appearance due to melanin production. These nuclei control movement, emotional response, and the ability to experience pleasure and pain.

Degeneration of the neurons within the substantia nigra is a hallmark of Parkinson disease. The midbrain is connected to both the cerebrum and the cerebellum.

On the anterolateral surfaces of the midbrain, motor tracts called cerebral peduncles run from the cerebrum to the spinal cord. Moreover, the midbrain is connected to the cerebellum through the superior cerebellar peduncle SCP , a bundle of myelinated axons. The pons is visible on the anterior surface of the brainstem as the thick bundle of white matter attached to the cerebellum. The name of the pons is derived from its connection to the cerebellum.

Those fibers are axons that project from the gray matter of the pons into the contralateral cerebellar cortex. Gray matter regions of the pons contain neurons receiving descending input from the forebrain that is sent to the cerebellum. The pons houses autonomic nuclei important for respiration.

The pons is also involved in sensory and motor information of some cranial nerves and houses the nuclei for cranial nerve V to VIII. The medulla oblongata is the region known as the myelencephalon in the embryonic brain.

In the posterior region of the medulla oblongata, these pyramids cross to the opposite side at a point called the decussation of pyramids. Due to this crossing, each hemisphere controls motor responses of the opposite side of the body. Inferior to each pyramid, a nucleus called inferior olive , is located and functions as a relay point for information on proprioception coming from the spinal cord and going into the cerebellum.

It also contains autonomic nuclei important for vital functions such as respiration, heart rate, and blood pressure, among others.

Basal Nuclei: Parkinson's Disease. These neurons release dopamine into the striatum. Without that modulatory influence, the basal nuclei are stuck in the indirect pathway, without the direct pathway being activated.

The direct pathway is responsible for increasing cortical movement commands. Currently, the most common way of doing that is by providing the amino acid L-DOPA, which is a precursor to the neurotransmitter dopamine and can cross the blood-brain barrier.

With levels of the precursor elevated, the remaining cells of the substantia nigra pars compacta can make more neurotransmitter and have a greater effect. Unfortunately, the patient will become less responsive to L-DOPA treatment as time progresses, and it can cause increased dopamine levels elsewhere in the brain, which are associated with psychosis or schizophrenia.

The white matter of the cerebellum is called arbor vitae "tree of life" for its appearance that reminds that of branches of a tree. The folds of the cerebellar cortex are called folia , which means "leaf". The cerebellum is divided into regions that are based on the particular functions and connections involved. The vermis connects the two cerebellar hemispheres.

Each hemisphere consists of two lobes, the anterior lobe and the posterior lobe , separated by the primary fissure. The lateral hemispheres are primarily concerned with planning motor functions through frontal lobe inputs that are returned through the thalamic projections back to the premotor and motor cortices.

Processing in the midline regions targets movements of the axial musculature, whereas the lateral regions target movements of the appendicular musculature. The cerebellum is responsible for coordination of movement, alternating movement of arms and legs, balance, posture and gait.

The five brain divisions are convenient for regionally categorizing the locations of brain components. After this lab, you should be able to identify brain divisions present in a brain section or gross brain specimen that you are asked to inspect. Note: The terms forebrain and hindbrain have clinical significance with respect to localizing lesions diagnostically in patients.

Another way to subdivide the brain is: cerebrum , cerebellum , and brainstem. The cerebrum has an outer layer - the cortex, which is composed of neurons and their supporting cells, and in living brain, has a gray color thus called the gray matter. Under the gray matter is the white matter, which is composed of myelinated ascending and descending nerve fibers, and in living brain have a white color. Embedded deep within the white matter are aggregates of neurons exhibiting gray color and known as subcortical nuclei.

The cerebral hemispheres are partially separate from each other along the midline by the interhemispheric fissure deep groove the falx cerebri Figure 1. The hemispheres are connected by a large C-shaped fiber bundle, the corpus callosum, which carries information between the two hemispheres.

For descriptive purposes each cerebral hemisphere can be divided into six lobes. Four of these lobes are named according to the overlying bones of the skull as follows: frontal, parietal, occipital and temporal Figures 1. Neither the insular lobe nor the limbic lobe is a true lobe.

Although the boundaries of the various lobes are somewhat arbitrary, the cortical areas in each lobe are histologically distinctive.

The surface of the cerebral cortex is highly convoluted with folds gyri , separate from each other by elongated grooves sulci. These convolutions allow for the expansion of the cortical surface area without increasing the size of the brain. On the lateral surface of the cerebral hemisphere there are two major deep grooves-sulci or fissure , the lateral fissure of Sylvian and the central sulci of Rolando , these sulci provide landmarks for topographical orientation Figure 1.

The central sulcus separates the frontal lobe from the parietal lobe and runs from the superior margin of the hemisphere near its midpoint obliquely downward and forward until it nearly meets the lateral fissure Figures 1.

The lateral fissure, separating the frontal and parietal lobes from the temporal lobe, begins inferiorly in the basal surface of the brain and extends laterally posteriorly and upward, separating the frontal and parietal lobes from the temporal lobe Figure 1. The frontal lobe is the portion which is rostral to the central sulcus and above the lateral fissure, and it occupies the anterior one third of the hemispheres Figures 1.

The boundaries of the parietal lobe are not precise, except for its rostral border — the central sulcus. The occipital lobe is the portion which is caudal to the parietal lobe Figures 1. Along the lateral surface of the hemisphere, an imaginary line connecting the tip of the parietal-occipital sulcus and the preoccipital notch Figure 1. On the medial surface of the hemisphere Figure 1. The temporal lobe lies ventral to the lateral sulcus, and on its lateral surface, it displays three diagonal oriented convolutions-the superior, middle, and inferior temporal gyri Figure 1.

The insula lies in the depths of the lateral sulcus. It has a triangular cortical area with gyri and sulci Figures 1. The limbic lobe consists of several cortical and subcortical areas Figure 1. The cerebral cortex is a functionally organized organ. A functionally organized system is a set of neurons linked together to convey a specific type s of information to accomplish a particular task.

It is possible to identify on the cerebral cortex primary sensory areas, secondary sensory areas, primary motor area, premotor area, supplementary motor area and association areas, which are devoted to the integration of motor and sensory information, intellectual activity, thinking and comprehension, execution of language, memory storage and recall.

The frontal lobe is the largest of the brain lobes and is comprised of four gyri, precentral gyrus that parallels the central sulcus, and three horizontal gyri: the superior , middle , and inferior frontal gyri. The inferior frontal gyrus is comprised of three parts: the orbital, the triangular and opercular. Finally, the straight gyrus gyrus rectus and the orbital gyri form the base of the frontal lobe Figure 1.

Four general functional areas are in the frontal lobe. They are the primary motor cortex, where all parts of the body are represented, the premotor and supplementary motor areas. The orbital portion of the prefrontal cortex is important in the appropriate switching between mental sets and the regulation of emotion.

The parietal lobe is comprised of three gyri: postcentral gyrus, superior and inferior parietal gyri Figure 1. The postcentral gyrus is immediately behind the central sulcus which forms its anterior boundary. The postcentral gyrus comprises the primary somatosensory cortex which is concerned with somatosensory reception, integration and processing sensory information from the surface of the body and from the viscera, and is important for the formulation of perception.

Caudal to the postcentral gyrus is the inferior parietal gyrus. The intraparietal sulcus separates the posterior parietal gyrus from the inferior parietal gyrus. The inferior parietal gyrus represents the cortical association area which integrates and processes sensory information from multiple modalities such as auditory and visual information.

The inferior parietal gyrus, which is known as Wernicke's area, is also important for language and reading skills, whereas the superior parietal gyrus is concerned with body image and spatial orientations. The temporal lobe is formed by three obliquely oriented gyri: the superior, middle, and inferior temporal gyri Figure 1. Inferomedial to the inferior temporal gyrus are the occipitotemporal and the parahippocampal gyri, which are separated by the collateral sulcus.

The upper surface of the superior temporal gyrus, which extends into the lateral fissure, is called the transverse temporal gyrus of Heschl and is the primary auditory cortex. The inferior part of the temporal lobe i. More medially is the parahippocampal gyrus, which is involved in learning and memory. Portions of the frontal, parietal, and temporal lobes, which are adjacent to the lateral sulcus and overlie the insular cortex, are known as the operculum.

The inferomedial surface of the temporal lobe is made up of the uncus and the parahippocampal gyrus medially. The inferior surface of the temporal lobe rests on the tentorium cerebelli. The occipital lobe is the most caudal part of the brain, lies on the tentorium cerebelli Figure 1. On its medial surface, there is a prominent fissure — the calcarine fissure and parieto-occipital sulcus.

The calcarine fissure sulcus and the parieto-occipital sulcus also define a cortical region known as the cuneus. The cuneus sulcus divides the occipital lobe into the cuneus dorsally and ventrally into the lingual gyrus. The occipital lobe contains the primary and higher-order visual cortex.

The insula lobe is located deep inside the lateral fissure and can be seen only when the temporal and the frontal lobes are separated Figures 1. The insula is characterized by several long gyri and sulci, the gyri breves and gyri longi.

There is some evidence that the insular cortical areas are involved in nociception and regulation of autonomic function.

The limbic lobe is not a true lobe and is comprised of several cortical regions such as the cingulate and parahippocampal gyri, some subcortical areas like the hippocampus, amygdala, septum, and other areas with their respective ascending and descending connections Figures 1.

The limbic lobe is involved in memory and learning, drive related behavior, and emotional function. There are subcortical areas in the telencephalon like the basal ganglia and the amygdaloid nucleus complex. The corpus callosum is a collection of nerve fibers that connect the two hemispheres. The corpus callosum is divided into rostrum head , body, the most rostrally part is the genu knee with connecting the rostrum and the body, and the splenium at the caudal extremity Figure 1.

The corpus callosum plays an important role in transferring information from one hemisphere to the other.