Hippocampus Definition
Hippocampus is a component of the brain belonging to the limbic system. It is a major component of the brain with a very important role in consolidating information in short-term memory and long-term memory and spatial navigation.Hippocampus Anatomy
Hippocampus is located in the medial temporal lobe and one of the components that makes up the edge of the cerebral cortex called limbic system. It is anatomically connected to the part of the brain that is responsible for emotional behavior.The shape of the hippocampus is very similar to that of the sea horse forming a curved tube. The name hippocampus was derived from its distinct shape similar to the sea horse. The comparison of hippocampus formation with the sea horse was first described by Venetian anatomist Julius Ceasar
Aranzi in 1587. The structure was first illustrated in 1729 by German anatomist Duvernoy.
The banana shaped structure is an appendage to the neocortex through a major gateway called enthorinal cortex. Hippocampus is a paired structure with two identical halves located on the left and right side of the brain. It is where different neuronal structures are neatly organized.
Hippocampus Functions
The main function of hippocampus is coordinating long-term memory, such as those related to personal events, and functions in spatial navigation.The hippocampus communicates with all parts of the neocortex through the enthorinal cortex. It was believed that hippocampus was also responsible for the olfaction although it was proven false.
Hippocampus Memory (Mention Loss Formation and Storage)
Hippocampus is vital in the formation of new autobiographical memory and facts memory. It serves as a gateway through which a memory must pass prior to permanent memory storage.Memories are not only a single aspect of experience but also include a lot of information such as those of learned information. The consolidation of memory takes place in many organizational levels of the brain where cellular changes and molecular changes take place within the first minute of information gathering leading to structural and functional changes in the sets of neurons.
Any damage or injury to the brain that can affect the hippocampus will affect the formation of new declarative memories as the hippocampus can no longer nor has the inability to connect with the mnemonic information that is distributed to the neurocortex before the memory can be consolidated.
A common form of dementia called Alzheimer’s disease is one form of brain disease affecting the brain function in controlling thought, memory and language. Hippocampus is also sensitive to global reduction in oxygen or global hypoxia.
Hippocampus Spatial Memory and Navigation
Spatial memory is described as cognitive process that enables an individual in recognizing different places and spatial relations between objects.The function of spatial memory is in recording information of environmental perception including spatial orientation. Spatial memory is one of the main functions of the hippocampus.
The consolidation of spatial memory and navigation enables an individual in traversing a direction. Spatial memory is dependent on the integrity of the hippocampus.
Hippocampus is theorized as cognitive map as a representation of layout of the environment. The cognitive map of environment enables an individual in maneuvering his direction towards a certain location. Evidence also showed that hippocampus plays a role in finding shorter routes in familiar places.
It is also evident through brain imaging that hippocampi are more active when correctly navigating.
Hippocampus Physiology
Hippocampus has two major modes of activity each with a distinct pattern of neural population activity and waves of electrical activity measured with a use of electroencephalogram. The modes are named after the EEG pattern theta and large irregular activity (LIA).Theta modes are recognized during alert behavior, state of activity and during rapid eye movement or REM in sleep. Hippocampus generates the largest EEG signal in any of the brain structure. This EEG pattern in travelling mode is known as the theta rhythm.
Large irregular activity or LIA mode can be recognized during state of waking immobility and slow-wave sleep or the non-dreaming sleep.
Theta and large irregular activity modes can both be seen in primates as well as with the rats. The exception is in the difficulty to recognize robust theta rhythm in the hippocampus of primates.
