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Hippocampus
The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the subiculum are components of the hippocampal formation located in the limbic system. The hippocampus plays important roles in the Memory consolidation, consolidation of information from short-term memory to long-term memory, and in spatial memory that enables Navigation#Navigation in spatial cognition, navigation. In humans, and other primates the hippocampus is located in the archicortex, one of the three regions of allocortex, in each cerebral hemisphere, hemisphere with direct neural projections to, and reciprocal indirect projections from the neocortex. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In Alzheimer's disease (and other forms of dementia), the hippocampus is one of the first regions of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seahorse
A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine Osteichthyes, bony fish in the genus ''Hippocampus''. The genus name comes from the Ancient Greek (), itself from () meaning "horse" and () meaning "sea monster" or "sea animal". Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail. Along with the pipefishes and seadragons (''Phycodurus'' and ''Phyllopteryx'') they form the family Syngnathidae. Evolution and fossil record Anatomical evidence, supported by molecular, physical, and genetic evidence, demonstrates that seahorses are highly modified pipefish. The fossil record of seahorses, however, is very sparse. The best known and best studied fossils are specimens of ''Hippocampus guttulatus'' (though literature more commonly refers to them under the synonym of ''H. ramulosus''), from the Marecchia River formation of Rimini Province, Italy, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spatial Memory
In cognitive psychology and neuroscience, spatial memory is a form of memory responsible for the recording and recovery of information needed to plan a course to a location and to recall the location of an object or the occurrence of an event. Spatial memory is necessary for orientation in space. Spatial memory can also be divided into egocentric and allocentric spatial memory. A person's spatial memory is required to navigate in a familiar city. A rat's spatial memory is needed to learn the location of food at the end of a maze. In both humans and animals, spatial memories are summarized as a cognitive map. Spatial memory has representations within working, short-term memory and long-term memory. Research indicates that there are specific areas of the brain associated with spatial memory. Many methods are used for measuring spatial memory in children, adults, and animals. Short-term spatial memory Short-term memory (STM) can be described as a system allowing one to temporarily ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippocampal Formation
The hippocampal formation is a compound structure in the medial temporal lobe of the brain. It forms a c-shaped bulge on the floor of the inferior horn of the lateral ventricle. Typically, the hippocampal formation is said to included the dentate gyrus, the hippocampus, and the subiculum. The presubiculum, parasubiculum, and the entorhinal cortex may also be included. The hippocampal formation is thought to play a role in memory, spatial navigation and control of attention. The neural layout and pathways within the hippocampal formation are very similar in all mammals. History and function During the nineteenth and early twentieth centuries, based largely on the observation that, between species, the size of the olfactory bulb varies with the size of the parahippocampal gyrus, the hippocampal formation was thought to be part of the olfactory system. In 1937, Papez theorized that a circuit (the Papez circuit) including the hippocampal formation constitutes the neural subst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limbic System
The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''Psychology''.sec. 3.20 Its various components support a variety of functions including emotion, behavior, long-term memory, and olfaction. The limbic system is involved in lower order emotional processing of input from sensory systems and consists of the amygdala, mammillary bodies, stria medullaris, central gray and dorsal and ventral nuclei of Gudden. This processed information is often relayed to a collection of structures from the telencephalon, diencephalon, and mesencephalon, including the prefrontal cortex, cingulate gyrus, limbic thalamus, hippocampus including the parahippocampal gyrus and subiculum, nucleus accumbens (limbic striatum), anterior hypothalamus, ventral tegmental area, midbrain raphe nuclei, habenular commi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subiculum
The subiculum (Latin for "support") also known as the subicular complex, or subicular cortex, is the most inferior component of the hippocampal formation. It lies between the entorhinal cortex and the CA1 hippocampal subfield. The subicular complex comprises a set of four related structures including the prosubiculum, presubiculum, postsubiculum and parasubiculum. Name The subiculum got its name from Karl Friedrich Burdach in his three-volume work ''Vom Bau und Leben des Gehirns'' (Vol. 2, §199). He originally named it subiculum cornu ammonis and so associated it with the rest of the hippocampal subfields. Structure The subicular complex receives input from CA1 and entorhinal cortical layer III pyramidal neurons and is the main output of the hippocampus proper. The pyramidal neurons send projections to the nucleus accumbens, septal nuclei, prefrontal cortex, lateral hypothalamus, nucleus reuniens, mammillary nuclei, entorhinal cortex and amygdala. The pyramidal neuro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentate Gyrus
The dentate gyrus (DG) is one of the subfields of the hippocampus, in the hippocampal formation. The hippocampal formation is located in the temporal lobe of the brain, and includes the hippocampus (including CA1 to CA4) subfields, and other subfields including the dentate gyrus, subiculum, and presubiculum. The dentate gyrus is part of the trisynaptic circuit, a neural circuit of the hippocampus, thought to contribute to the formation of new episodic memories, the spontaneous exploration of novel environments and other functions. The dentate gyrus has toothlike projections from which it is named. The subgranular zone of the dentate gyrus is one of only two major sites of adult neurogenesis in the brain, and is found in many mammals. The other main site is the subventricular zone in the ventricular system. Other sites may include the striatum and the cerebellum. However, whether significant neurogenesis takes place in the adult human dentate gyrus has been a matter of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Consolidation
Memory consolidation is a category of processes that stabilize a memory trace after its initial acquisition. A memory trace is a change in the nervous system caused by memorizing something. Consolidation is distinguished into two specific processes. The first, synaptic consolidation, which is thought to correspond to long-term potentiation#Late phase, late-phase long-term potentiation, occurs on a small scale in the synaptic connections and neural circuits within the first few hours after learning. The second process is systems consolidation, occurring on a much larger scale in the brain, rendering Declarative memory, hippocampus-dependent memories independent of the hippocampus over a period of weeks to years. Recently, a third process has become the focus of research, reconsolidation, in which previously consolidated memories can be made Lability, labile again through reactivation of the memory trace. History Memory consolidation was first referred to in the writings of the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archicortex
The archicortex, or archipallium, is the phylogenetically second oldest region of the brain's cerebral cortex (the oldest is the paleocortex). In older species, such as fish, the archipallium makes up most of the cerebrum. Amphibians develop an archipallium and paleopallium. In humans, the archicortex makes up the three cortical layers of the hippocampus. It has fewer cortical layers than both the neocortex, which has six, and the paleocortex, which has either four or five. The archicortex, along with the paleocortex and periallocortex, is a subtype of allocortex. Because the number of cortical layers that make up a type of cortical tissue seems to be directly proportional to both the information-processing capabilities of that tissue and its phylogenetic age, the archicortex is thought to be the oldest and most basic type of cortical tissue. Location The archicortex is most prevalent in the olfactory cortex and the hippocampus, which are responsible for processing smells ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-term Memory
Long-term memory (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to sensory memory, the initial stage, and short-term or working memory, the second stage, which persists for about 18 to 30 seconds. LTM is grouped into two categories known as explicit memory (declarative memory) and implicit memory (non-declarative memory). Explicit memory is broken down into episodic and semantic memory, while implicit memory includes procedural memory and emotional conditioning. Stores The idea of separate memories for short- and long-term storage originated in the 19th century. One model of memory developed in the 1960s assumed that all memories are formed in one store and transfer to another store after a small period of time. This model is referred to as the "modal model", most famously detailed by Shiffrin. The model states that memory is first stored in sensory memory, which has a large capacit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as visual perception, vision, hearing, and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing that information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system). While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective segmentation (biology), body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a brain vesicle, vesicular enlargement at the rostral (anatomical term), rostral end of the neural tube, with centralized control over all body segments. All vertebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alzheimer's Disease
Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems with language, disorientation (including easily getting lost), mood swings, loss of motivation, self-neglect, and behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the average life expectancy following diagnosis is three to twelve years. The causes of Alzheimer's disease remain poorly understood. There are many environmental and genetic risk factors associated with its development. The strongest genetic risk factor is from an allele of apolipoprotein E. Other risk factors include a history of head injury, clinical depression, and high blood pressure. The progression of the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Brain
The human brain is the central organ (anatomy), organ of the nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activities of the human body, body, processing, integrating, and coordinating the information it receives from the sensory nervous system. The brain integrates sensory information and coordinates instructions sent to the rest of the body. The cerebrum, the largest part of the human brain, consists of two cerebral hemispheres. Each hemisphere has an inner core composed of white matter, and an outer surface – the cerebral cortex – composed of grey matter. The cortex has an outer layer, the neocortex, and an inner allocortex. The neocortex is made up of six Cerebral cortex#Layers of neocortex, neuronal layers, while the allocortex has three or four. Each hemisphere is divided into four lobes of the brain, lobes – the frontal lobe, frontal, pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
