What Happens in the Brain When you sleep

First we need to understand the DEEP STRUCTURES OF THE BRAIN


lentiform nucleus

n.

The large, cone-shaped mass of gray matter that forms the central core of the cerebral hemisphere, whose convex base is formed by the putamen and whose apical part consists of the globus pallidus. Also called lenticular nucleus.

Caudate Nucleus
The caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system.


SUBSTANTIA NIGRA

Role of the Basal Ganglia The basal ganglia play a complex and integral role in the control of movement: Selecting and maintaining purposeful motor activity while suppressing unwanted or useless movement. Helping monitor and coordinate slow, sustained contractions related to posture and support. Inhibiting muscle tone throughout the body (proper muscle tone is normally maintained through a balance of excitatory and inihibtory inputs to the neurons that inervate skeletal muscle). Compare the basal ganglia’s functions with thesymptoms of Parkinson’s disease. Anatomy of the Basal Ganglia src: Bear, M. F., Connors, B.W. & Paradiso M. A.,Neuroscience: Exploring the Brain, Second Edition, Lippincott Williams & Wilkins, 2001, pp 473-482. The basal ganglia consists of thestriatum, the globus pallidus and thesubthalamic nucleus. Thestriatum is the target of cortical input to the basal ganglia and can be divided into the caudate nucleus and the putamen. The globus pallidus is the source of output to the thalamus and can be divided into an internal and external segment. The substantia nigra is a midbrain structure that is reciprocally connected with the basal ganglia of the forebrain. The Basal Ganglia and Movement The command to initiate movement is implemented with the participation of subthalamic input to the SMA and PMC arising from the ventral lateral (VL) nucleus of the dorsal thalamus. The input to this part of the VL arises from the basal ganglia. The basal ganglia, in turn, receive input from the cerebral cortex, particularly the frontal, prefrontal and parietal cortex. Hence information cycles from the cortex, to the basal ganglia and thalamus, and back to the cortex again, forming a loop that functions in the selection and initiation of willed movements. Sources: Parkinson’s Disease site from Evergreen State College; Bear, M. F., Connors, B.W. & Paradiso M. A., Neuroscience: Exploring the Brain, Second Edition, 351 West Camden St., Baltimore, MD: Lippincott Williams & Wilkins, 2001, pp 473-482 The amygdalae (Latin, also corpus amygdaloideum, singular amygdala, from Greekαμυγδαλή, amygdalē, 'almond', 'tonsil', listed in theGray's Anatomy as the nucleus amygdalæ)[1] are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans.[2] Shown in research to perform a primary role in the processing andmemory of emotional reactions, the amygdalae are considered part of the limbic system.[3]. The Cingulate Cortex: The cingulate cortex is a part of the brainsituated in the medial aspect of the cortex. It includes the cortex of the cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus. The cingulate cortex is usually considered part of the limbic lobe, separate from the adjacentfrontal and parietal lobes. It receives inputs from the thalamus and theneocortex, and projects to the entorhinal cortexvia the cingulum. It is an integral part of thelimbic system, which is involved with emotion formation and processing, learning, and memory, and is also important for executive function and respiratory control. The Hippocampus The hippocampus is a major component of the brains of humans and other mammals. It belongs to the limbic system and plays important roles in long-term memory and spatial navigation. Like the cerebral cortex, with which it is closely associated, it is a paired structure, with mirror-image halves in the left and right sides of the brain. In humans and other primates, the hippocampus is located inside the medial temporal lobe, beneath the cortical surface. In Alzheimer's disease the hippocampus is one of the first regions of the brain to suffer damage; memory problems and disorientation appear among the first symptoms. Damage to the hippocampus can also result from oxygen starvation (hypoxia), encephalitis, or medial temporal lobe epilepsy. People with extensive hippocampal damage may experience amnesia—the inability to form or retain new memories. In rodents, the hippocampus has been studied extensively as part of the brain system responsible for spatial memory and navigation. Many neurons in the rat and mouse hippocampus respond as place cells: that is, they fire bursts of action potentials when the animal passes through a specific part of its environment. Hippocampal place cells interact extensively with head direction cells, whose activity acts as an inertial compass, and with grid cells in the neighboring entorhinal cortex. Since different neuronal cell types are neatly organized into layers in the hippocampus, it has frequently been used as a model system for studying neurophysiology. The form of neural plasticity known as long-term potentiation (LTP) was first discovered to occur in the hippocampus and has often been studied in this structure. LTP is widely believed to be one of the main neural mechanisms by which memory is stored in the brain.