SUMMARY / RELATED TOPICS

Hippocampus

The hippocampus is a major component of the brain of humans and other vertebrates. Humans and other mammals have one in each side of the brain; the hippocampus is part of the limbic system, plays important roles in the consolidation of information from short-term memory to long-term memory, in spatial memory that enables navigation. The hippocampus is located under the cerebral cortex in the allocortex, in primates it is in the medial temporal lobe, it contains two main interlocking parts: the dentate gyrus. In Alzheimer's disease, the hippocampus is one of the first regions of the brain to suffer damage. Damage to the hippocampus can result from oxygen starvation, encephalitis, or medial temporal lobe epilepsy. People with extensive, bilateral hippocampal damage may experience anterograde amnesia: the inability to form and retain new memories. Since different neuronal cell types are neatly organized into layers in the hippocampus, it has been used as a model system for studying neurophysiology.

The form of neural plasticity known as long-term potentiation was discovered to occur in the hippocampus and has been studied in this structure. LTP is believed to be one of the main neural mechanisms by which memories are stored in the brain. In rodents as model organisms, the hippocampus has been studied extensively as part of a 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, conjecturally with grid cells in the neighboring entorhinal cortex; the earliest description of the ridge running along the floor of the temporal horn of the lateral ventricle comes from the Venetian anatomist Julius Caesar Aranzi, who likened it first to a silkworm and to a seahorse. The German anatomist Duvernoy, the first to illustrate the structure wavered between "seahorse" and "silkworm".

"Ram's horn" was proposed by the Danish anatomist Jacob Winsløw in 1732. This has survived in abbreviated form as CA in naming the subfields of the hippocampus. Another reference appeared with the term pes hippocampi, which may date back to Diemerbroeck in 1672, introducing a comparison with the shape of the folded back forelimbs and webbed feet of the mythological hippocampus, a sea-monster with a horse's forequarters and a fish's tail; the hippocampus was described as pes hippocampi major, with an adjacent bulge in the occipital horn, described as the pes hippocampi minor and renamed as the calcar avis. The renaming of the hippocampus as hippocampus major, the calcar avis as hippocampus minor, has been attributed to Félix Vicq-d'Azyr systematising nomenclature of parts of the brain in 1786. Mayer mistakenly used the term hippopotamus in 1779, was followed by some other authors until Karl Friedrich Burdach resolved this error in 1829. In 1861 the hippocampus minor became the centre of a dispute over human evolution between Thomas Henry Huxley and Richard Owen, satirised as the Great Hippocampus Question.

The term hippocampus minor fell from use in anatomy textbooks, was removed in the Nomina Anatomica of 1895. Today, the structure is just called the hippocampus, with the term Cornu Ammonis surviving in the names of the hippocampal subfields CA1-CA4; the term limbic system was introduced in 1952 by Paul MacLean to describe the set of structures that line the edge of the cortex: These include the hippocampus, cingulate cortex, olfactory cortex, amygdala. Paul MacLean suggested that the limbic structures comprise the neural basis of emotion; the hippocampus is anatomically connected to parts of the brain that are involved with emotional behavior—the septum, the hypothalamic mammillary body, the anterior nuclear complex in the thalamus, is accepted to be part of the limbic system. The hippocampus can be seen as a ridge of gray matter tissue, elevating from the floor of each lateral ventricle in the region of the inferior or temporal horn; this ridge can be seen as an inward fold of the archicortex into the medial temporal lobe.

The hippocampus can only be seen in dissections. The cortex thins from six layers to the four layers that make up the hippocampus; the term hippocampal formation is used to refer to its related parts. However, there is no consensus as to. Sometimes the hippocampus is said to include the subiculum; some references include the dentate gyrus and the subiculum in the hippocampal formation, others include the presubiculum and entorhinal cortex. The neural layout and pathways within the hippocampal formation are similar in all mammals; the hippocampus, including the dentate gyrus, has the shape of a curved tube, compared to a seahorse, a ram's horn. Its abbreviation CA is used in naming the hippocampal subfields CA1, CA2, CA3, CA4, it can be distinguished as an area where the cortex narrows into a single layer of dens

Serenade (ballet)

Serenade is a ballet by George Balanchine to Tschaikovsky's 1880 Serenade for Strings in C, Op. 48. Students of the School of American Ballet gave the first performance on Sunday, 10 June 1934 on the Felix M. Warburg estate in White Plains, N. Y. where Mozartiana had been danced the previous day. This was the first ballet, it was presented by the Producing Company of the School of American Ballet on 6 December at the Avery Memorial Theatre of the Wadsworth Atheneum with sets by the painter William Littlefield. Balanchine presented the ballet as his response to the generous sponsorships he received during his immigration to America; the official premiere took place on 1 March 1935 with the American Ballet at the Adelphi Theatre, New York, conducted by Sandor Harmati. NYCB principal dancer Philip Neal chose to include Serenade in his farewell performance on Sunday, 13 June 2010; the blue tutus used in Serenade inspired the naming of the Balanchine crater on the planet Mercury. The work can be considered a bridge between his two early works for Sergei Diaghilev and his less episodic American works.

The dance is characterized by two falls, a choreographic allusion to Giselle, but an element in the Khorumi, a Georgian folk dance which influenced Balanchine. NY Times of Marie-Jeanne by Jack Anderson, January 3, 2008

Avgolemono

Avgolemono, avgolémono or egg–lemon sauce, is a family of sauces and soups made with egg yolk and lemon juice mixed with broth, heated until they thicken. They are found in Greek, Arab, Sephardic Jewish and Italian cuisine. In Sephardic Jewish cuisine, it is called agristada or salsa blanco, in Italian cuisine, bagna brusca, brodettato, or brodo brusco. In Arabic, it is called tarbiya or beida bi-lemoune'egg with lemon', it is widely used in Balkan cuisine. As a sauce, it is used for warm dolma, for vegetables like artichokes, for stew-like dishes where the egg-lemon mixture is used to thicken the cooking juices, such as the Greek pork with celery and the Turkish ekşili köfte. In some Middle Eastern cuisines, it is used as a sauce for chicken or fish. Among Italian Jews, it is served as a sauce for meat; as a soup, it starts with chicken broth, though meat, fish, or vegetable broths are used. Rice, pastina, or tapioca are cooked in the broth before the mixture of eggs and lemon is added, its consistency varies from near-stew to near-broth.

It is served with pieces of the meat and vegetables reserved from the broth. Magiritsa soup is a Greek avgolemono soup of lamb offal served to break the fast of Great Lent; the soup is made with whole eggs, but sometimes with just yolks. The whites may be beaten into a foam separately before mixing with the yolks and lemon juice, or whole eggs may be beaten with the lemon juice; the starch of the pasta or rice contributes to stabilizing the emulsion. Agristada was made by Jews in Iberia before the expulsion from Spain with verjuice, pomegranate juice, or bitter orange juice, but not vinegar. In periods, lemon became the standard souring agent. List of egg dishes List of lemon dishes and beverages List of sauces List of soups Alan Davidson, The Oxford Companion to Food, Oxford, 1999. ISBN 0-19-211579-0