Thalamus
Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.
Thalamic Nuclei
Several groups of nuclei in the thalamus that serve as the major relay centers for sensory impulses in the brain.
Ventral Thalamic Nuclei
A large group of nuclei lying between the internal medullary lamina and the INTERNAL CAPSULE. It includes the ventral anterior, ventral lateral, and ventral posterior nuclei.
Mediodorsal Thalamic Nucleus
The largest of the medial nuclei of the thalamus. It makes extensive connections with most of the other thalamic nuclei.
Thalamic Diseases
Disorders of the centrally located thalamus, which integrates a wide range of cortical and subcortical information. Manifestations include sensory loss, MOVEMENT DISORDERS; ATAXIA, pain syndromes, visual disorders, a variety of neuropsychological conditions, and COMA. Relatively common etiologies include CEREBROVASCULAR DISORDERS; CRANIOCEREBRAL TRAUMA; BRAIN NEOPLASMS; BRAIN HYPOXIA; INTRACRANIAL HEMORRHAGES; and infectious processes.
Brain
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
Intralaminar Thalamic Nuclei
Anterior Thalamic Nuclei
Three nuclei located beneath the dorsal surface of the most rostral part of the thalamus. The group includes the anterodorsal nucleus, anteromedial nucleus, and anteroventral nucleus. All receive connections from the MAMILLARY BODY and BRAIN FORNIX, and project fibers to the CINGULATE BODY.
Posterior Thalamic Nuclei
A transitional diencephalic zone of the thalamus consisting of complex and varied cells lying caudal to the VENTRAL POSTEROLATERAL NUCLEUS, medial to the rostral part of the PULVINAR, and dorsal to the MEDIAL GENICULATE BODY. It contains the limitans, posterior, suprageniculate, and submedial nuclei.
Magnetic Resonance Imaging
Midline Thalamic Nuclei
Cerebral Cortex
Geniculate Bodies
Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.
Brain Mapping
Pulvinar
Large mass of nuclei forming the most caudal portion of the THALAMUS and overhanging the GENICULATE BODIES and the dorsolateral surface of the MIDBRAIN. It is divided into four parts: the lateral, medial, inferior, and oral pulvinar nuclei.
Neurons
Basal Ganglia
Lateral Thalamic Nuclei
A narrow strip of cell groups on the dorsomedial surface of the thalamus. It includes the lateral dorsal nucleus, lateral posterior nucleus, and the PULVINAR.
Vibrissae
Spinothalamic Tracts
A bundle of NERVE FIBERS connecting each posterior horn of the spinal cord to the opposite side of the THALAMUS, carrying information about pain, temperature, and touch. It is one of two major routes by which afferent spinal NERVE FIBERS carrying sensations of somaesthesis are transmitted to the THALAMUS.
Diencephalon
The paired caudal parts of the PROSENCEPHALON from which the THALAMUS; HYPOTHALAMUS; EPITHALAMUS; and SUBTHALAMUS are derived.
Afferent Pathways
Somatosensory Cortex
Area of the parietal lobe concerned with receiving sensations such as movement, pain, pressure, position, temperature, touch, and vibration. It lies posterior to the central sulcus.
Epilepsy, Absence
A childhood seizure disorder characterized by rhythmic electrical brain discharges of generalized onset. Clinical features include a sudden cessation of ongoing activity usually without loss of postural tone. Rhythmic blinking of the eyelids or lip smacking frequently accompanies the SEIZURES. The usual duration is 5-10 seconds, and multiple episodes may occur daily. Juvenile absence epilepsy is characterized by the juvenile onset of absence seizures and an increased incidence of myoclonus and tonic-clonic seizures. (Menkes, Textbook of Child Neurology, 5th ed, p736)
Putamen
The largest and most lateral of the BASAL GANGLIA lying between the lateral medullary lamina of the GLOBUS PALLIDUS and the EXTERNAL CAPSULE. It is part of the neostriatum and forms part of the LENTIFORM NUCLEUS along with the GLOBUS PALLIDUS.
Auditory Pathways
NEURAL PATHWAYS and connections within the CENTRAL NERVOUS SYSTEM, beginning at the hair cells of the ORGAN OF CORTI, continuing along the eighth cranial nerve, and terminating at the AUDITORY CORTEX.
Caudate Nucleus
Elongated gray mass of the neostriatum located adjacent to the lateral ventricle of the brain.
Mamillary Bodies
Subthalamus
A transition zone in the anterior part of the diencephalon interposed between the thalamus, hypothalamus, and tegmentum of the mesencephalon. Components of the subthalamus include the SUBTHALAMIC NUCLEUS, zona incerta, nucleus of field H, and the nucleus of ansa lenticularis. The latter contains the ENTOPEDUNCULAR NUCLEUS.
Image Processing, Computer-Assisted
Globus Pallidus
The representation of the phylogenetically oldest part of the corpus striatum called the paleostriatum. It forms the smaller, more medial part of the lentiform nucleus.
Brain Stem
The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.
Nerve Net
A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.
Rats, Sprague-Dawley
Stereotaxic Techniques
Techniques used mostly during brain surgery which use a system of three-dimensional coordinates to locate the site to be operated on.
Rats, Long-Evans
An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.
Action Potentials
Limbic System
A set of forebrain structures common to all mammals that is defined functionally and anatomically. It is implicated in the higher integration of visceral, olfactory, and somatic information as well as homeostatic responses including fundamental survival behaviors (feeding, mating, emotion). For most authors, it includes the AMYGDALA; EPITHALAMUS; GYRUS CINGULI; hippocampal formation (see HIPPOCAMPUS); HYPOTHALAMUS; PARAHIPPOCAMPAL GYRUS; SEPTAL NUCLEI; anterior nuclear group of thalamus, and portions of the basal ganglia. (Parent, Carpenter's Human Neuroanatomy, 9th ed, p744; NeuroNames, http://rprcsgi.rprc.washington.edu/neuronames/index.html (September 2, 1998)).
Deep Brain Stimulation
Therapy for MOVEMENT DISORDERS, especially PARKINSON DISEASE, that applies electricity via stereotactic implantation of ELECTRODES in specific areas of the BRAIN such as the THALAMUS. The electrodes are attached to a neurostimulator placed subcutaneously.
Electroencephalography
Neural Inhibition
The function of opposing or restraining the excitation of neurons or their target excitable cells.
Cerebellum
The part of brain that lies behind the BRAIN STEM in the posterior base of skull (CRANIAL FOSSA, POSTERIOR). It is also known as the "little brain" with convolutions similar to those of CEREBRAL CORTEX, inner white matter, and deep cerebellar nuclei. Its function is to coordinate voluntary movements, maintain balance, and learn motor skills.
Functional Laterality
Visual Pathways
Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.
Cats
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Cerebrovascular Circulation
The circulation of blood through the BLOOD VESSELS of the BRAIN.
Tomography, Emission-Computed
Prosencephalon
The anterior of the three primitive cerebral vesicles of the embryonic brain arising from the NEURAL TUBE. It subdivides to form DIENCEPHALON and TELENCEPHALON. (Stedmans Medical Dictionary, 27th ed)
Reticular Formation
A region extending from the PONS & MEDULLA OBLONGATA through the MESENCEPHALON, characterized by a diversity of neurons of various sizes and shapes, arranged in different aggregations and enmeshed in a complicated fiber network.
Tremor
Cyclical movement of a body part that can represent either a physiologic process or a manifestation of disease. Intention or action tremor, a common manifestation of CEREBELLAR DISEASES, is aggravated by movement. In contrast, resting tremor is maximal when there is no attempt at voluntary movement, and occurs as a relatively frequent manifestation of PARKINSON DISEASE.
Efferent Pathways
Autoradiography
Auditory Cortex
The region of the cerebral cortex that receives the auditory radiation from the MEDIAL GENICULATE BODY.
Electrodes, Implanted
Surgically placed electric conductors through which ELECTRIC STIMULATION is delivered to or electrical activity is recorded from a specific point inside the body.
Trigeminal Nuclei
Nuclei of the trigeminal nerve situated in the brain stem. They include the nucleus of the spinal trigeminal tract (TRIGEMINAL NUCLEUS, SPINAL), the principal sensory nucleus, the mesencephalic nucleus, and the motor nucleus.
Atrophy
Corpus Striatum
Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.
Evoked Potentials
Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.
Amygdala
Almond-shaped group of basal nuclei anterior to the INFERIOR HORN OF THE LATERAL VENTRICLE of the TEMPORAL LOBE. The amygdala is part of the limbic system.
Synaptic Transmission
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Myoclonic Epilepsy, Juvenile
A disorder characterized by the onset of myoclonus in adolescence, a marked increase in the incidence of absence seizures (see EPILEPSY, ABSENCE), and generalized major motor seizures (see EPILEPSY, TONIC-CLONIC). The myoclonic episodes tend to occur shortly after awakening. Seizures tend to be aggravated by sleep deprivation and alcohol consumption. Hereditary and sporadic forms have been identified. (From Adams et al., Principles of Neurology, 6th ed, p323)
Basal Ganglia Diseases
Diseases of the BASAL GANGLIA including the PUTAMEN; GLOBUS PALLIDUS; claustrum; AMYGDALA; and CAUDATE NUCLEUS. DYSKINESIAS (most notably involuntary movements and alterations of the rate of movement) represent the primary clinical manifestations of these disorders. Common etiologies include CEREBROVASCULAR DISORDERS; NEURODEGENERATIVE DISEASES; and CRANIOCEREBRAL TRAUMA.
Evoked Potentials, Somatosensory
The electric response evoked in the CEREBRAL CORTEX by stimulation along AFFERENT PATHWAYS from PERIPHERAL NERVES to CEREBRUM.
Mesencephalon
The middle of the three primitive cerebral vesicles of the embryonic brain. Without further subdivision, midbrain develops into a short, constricted portion connecting the PONS and the DIENCEPHALON. Midbrain contains two major parts, the dorsal TECTUM MESENCEPHALI and the ventral TEGMENTUM MESENCEPHALI, housing components of auditory, visual, and other sensorimoter systems.
Positron-Emission Tomography
An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. It has been useful in study of soft tissues such as CANCER; CARDIOVASCULAR SYSTEM; and brain. SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography, but uses isotopes with longer half-lives and resolution is lower.
Wakefulness
Diffusion Magnetic Resonance Imaging
A diagnostic technique that incorporates the measurement of molecular diffusion (such as water or metabolites) for tissue assessment by MRI. The degree of molecular movement can be measured by changes of apparent diffusion coefficient (ADC) with time, as reflected by tissue microstructure. Diffusion MRI has been used to study BRAIN ISCHEMIA and tumor response to treatment.
Pons
The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.
Brain Chemistry
Essential Tremor
A relatively common disorder characterized by a fairly specific pattern of tremors which are most prominent in the upper extremities and neck, inducing titubations of the head. The tremor is usually mild, but when severe may be disabling. An autosomal dominant pattern of inheritance may occur in some families (i.e., familial tremor). (Mov Disord 1988;13(1):5-10)
Muscimol
A neurotoxic isoxazole isolated from species of AMANITA. It is obtained by decarboxylation of IBOTENIC ACID. Muscimol is a potent agonist of GABA-A RECEPTORS and is used mainly as an experimental tool in animal and tissue studies.
Diffusion Tensor Imaging
The use of diffusion ANISOTROPY data from diffusion magnetic resonance imaging results to construct images based on the direction of the faster diffusing molecules.
Pain
An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.
Models, Neurological
Hippocampus
A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.
Internal Capsule
Receptors, GABA-A
Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop.
Macaca fascicularis
Neocortex
The largest portion of the CEREBRAL CORTEX in which the NEURONS are arranged in six layers in the mammalian brain: molecular, external granular, external pyramidal, internal granular, internal pyramidal and multiform layers.
Electrophysiology
Prefrontal Cortex
The rostral part of the frontal lobe, bounded by the inferior precentral fissure in humans, which receives projection fibers from the MEDIODORSAL NUCLEUS OF THE THALAMUS. The prefrontal cortex receives afferent fibers from numerous structures of the DIENCEPHALON; MESENCEPHALON; and LIMBIC SYSTEM as well as cortical afferents of visual, auditory, and somatic origin.
Cerebral Infarction
The formation of an area of NECROSIS in the CEREBRUM caused by an insufficiency of arterial or venous blood flow. Infarcts of the cerebrum are generally classified by hemisphere (i.e., left vs. right), lobe (e.g., frontal lobe infarction), arterial distribution (e.g., INFARCTION, ANTERIOR CEREBRAL ARTERY), and etiology (e.g., embolic infarction).
Photic Stimulation
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
Frontal Lobe
Thiamine Deficiency
A nutritional condition produced by a deficiency of THIAMINE in the diet, characterized by anorexia, irritability, and weight loss. Later, patients experience weakness, peripheral neuropathy, headache, and tachycardia. In addition to being caused by a poor diet, thiamine deficiency in the United States most commonly occurs as a result of alcoholism, since ethanol interferes with thiamine absorption. In countries relying on polished rice as a dietary staple, BERIBERI prevalence is very high. (From Cecil Textbook of Medicine, 19th ed, p1171)
Synapses
Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.