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Oct 30, 2023 · The hippocampus is a paired structure present in each temporal lobe of the brain. It takes its name from the Greek word for the seahorse, because it resembles this small upright-swimming fish. The hippocampus is part of a larger structure of the temporal lobe called the hippocampal formation. The hippocampal formation extends from the amygdala ...
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Jul 20, 2023 · The hippocampus is the "flash drive" of the human brain and is often associated with memory consolidation and decision-making, but it is far more complex in structure and function than a flash drive. The hippocampus is a convex elevation of gray matter tissue within the parahippocampal gyrus inside the inferior temporal horn of the lateral ventricle. One can describe it more holistically as a ...
- 2023/07/20
- Overview
- Anatomy of the hippocampus
- Principal neural circuits
- Morphological distinctions
- Sources of input
- Functions of the hippocampus
hippocampus, region of the brain that is associated primarily with memory. The name hippocampus is derived from the Greek hippokampus (hippos, meaning “horse,” and kampos, meaning “sea monster”), since the structure’s shape resembles that of a sea horse. The hippocampus, which is located in the inner (medial) region of the temporal lobe, forms part...
The anatomy of the hippocampus is of chief importance to its function. The hippocampus receives input from and sends output to the rest of the brain via a structure known as the entorhinal cortex, which is located beneath the anterior (frontal) region of the hippocampus. The hippocampal formation itself is composed of several subregions, which incl...
The subregions of the hippocampus are connected by two principal neural circuits: the trisynaptic circuit and the monosynaptic circuit. The trisynaptic circuit forwards information from the entorhinal cortex to the dentate gyrus via the perforant path, which perforates through the subiculum. Information then flows from the dentate gyrus to CA3 via ...
The CA fields contain three layers (in contrast to the rest of the brain’s six-layered cortex) and use pyramidal cells (neurons with dendrites that spread to give the cell body a triangular appearance) as the principal excitatory cells. The CA3 region of the hippocampus contains a large excitatory recurrent collateral network (where axons loop back to input fibres, or dendrites), which constitutes the largest input source to CA3.
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The dentate gyrus is morphologically distinct from CA fields and contains densely packed granule cells (neurons with relatively small cell bodies). The dentate gyrus is also one of only two regions in the brain known to house neural stem cells that are capable of differentiating into new neurons throughout adulthood.
The hippocampus receives input from modulatory neurotransmitter systems, including serotonin, norepinephrine, and dopamine systems. It also receives cholinergic input (responds to the neurotransmitter acetylcholine) from the medial septum, which regulates the hippocampal physiological state. The medial septum is involved in setting one of the critical oscillatory rhythms in the hippocampus, the theta rhythm. Abolishing that region or the associated theta rhythm interferes with hippocampal function.
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The two most-influential theories for hippocampal function are related to space and memory. The spatial hypothesis was supported by the seminal discovery in 1971 of cells in the hippocampus that fired bursts of action potentials when a rat traversed specific locations in space, or “place fields.” That suggested that the hippocampus was a sort of device used by the brain for mapping layouts of the environment. Data supporting that idea came from later virtual navigation studies in humans, which suggested a strong association between the hippocampus and spatial navigation. The memory hypothesis originated in 1957 and was supported by studies and observations in which hippocampal removal resulted in a loss of the ability to form new memories, particularly fact- and event-related (declarative) memories.
Although there is near universal agreement among scientists that the hippocampus is important for memory, the exact processes by which the hippocampus supports memory are subject to much debate. Some studies suggest that the hippocampus binds items and contexts into unified experiences and stores them. Other studies suggest that the hippocampus is preferentially involved in conscious recollection, or the experience of mental time travel during recall. Still other studies suggest that the hippocampus is able to support rapid learning by reducing interference among similar memories (for example, where a person parked his or her car today versus yesterday). Some theories of hippocampal function treat the hippocampus as an index (much like an index at the end of a book) that binds together elements of an experience but does not store the experience itself. The latter is assumed to be stored in a distributed fashion throughout the brain, while the hippocampus is assumed to possess an index of that distributed code.
Sep 19, 2023 · In psychology, the hippocampus is a crucial structure within the brain's medial temporal lobe. It plays a vital role in forming and retrieving memories, spatial navigation, and emotional responses. Damage to the hippocampus can lead to memory impairments and difficulty forming new memories, highlighting its importance in learning and cognition.
Hippocampus. The hippocampus is a part of your brain that’s responsible for your memory and learning. This small structure helps you remember, both short- and long-term, and gain awareness from your environment. The hippocampus is at risk of injury or damage from underlying conditions like Alzheimer’s disease. Contents Overview Function ...
Hippocampus anatomy describes the physical aspects and properties of the hippocampus, a neural structure in the medial temporal lobe of the brain. It has a distinctive, curved shape that has been likened to the sea-horse monster of Greek mythology and the ram's horns of Amun in Egyptian mythology. This general layout holds across the full range ...
The hippocampus ( pl.: hippocampi; via Latin from Greek ἱππόκαμπος, ' seahorse ') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, and plays important roles in the consolidation of information ...
