The entorhinal cortex (EC) is an area of the brain's allocortex, located in the medial temporal lobe, whose functions include being a widespread network hub for memory, navigation, and the perception of time. The EC is the main interface between the hippocampus and neocortex. The EC-hippocampus system plays an important role in declarative (autobiographical/episodic/semantic) memories and in particular spatial memories including memory formation, memory consolidation, and memory optimization in sleep. The EC is also responsible for the pre-processing (familiarity) of the input signals in the reflex nictitating membrane response of classical trace conditioning; the association of impulses from the eye and the ear occurs in the entorhinal cortex.
The hippocampus 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 from short-term memory to long-term memory, and in spatial memory that enables navigation. The hippocampus is located in the allocortex, with neural projections into the neocortex, in humans as well as other primates. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In humans, it contains two main interlocking parts: the hippocampus proper, and the dentate gyrus.
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.
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The entorhinal cortex (EC) is a major part of the hippocampal formation of the brain, and is reciprocally connected with the hippocampus.
Explicit memory is one of the two main types of long-term human memory, the other of which is implicit memory. Explicit memory is the conscious, intentional recollection of factual information, previous experiences, and concepts. This type of memory is dependent upon three processes: acquisition, consolidation, and retrieval.
The parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus and is part of the limbic system. The region plays an important role in memory encoding and retrieval. It has been involved in some cases of hippocampal sclerosis. Asymmetry has been observed in schizophrenia.
The lobes of the brain are the major identifiable zones of the human cerebral cortex, and they comprise the surface of each hemisphere of the cerebrum. The two hemispheres are roughly symmetrical in structure, and are connected by the corpus callosum. They traditionally have been divided into four lobes, but are today considered as having six lobes each. The lobes are large areas that are anatomically distinguishable, and are also functionally distinct to some degree. Each lobe of the brain has numerous ridges, or gyri, and furrows, the sulci that constitute further subzones of the cortex. The expression "lobes of the brain" usually refers only to those of the cerebrum, not to the distinct areas of the cerebellum.
The inferior temporal gyrus is one of three gyri of the temporal lobe and is located below the middle temporal gyrus, connected behind with the inferior occipital gyrus; it also extends around the infero-lateral border on to the inferior surface of the temporal lobe, where it is limited by the inferior sulcus. This region is one of the higher levels of the ventral stream of visual processing, associated with the representation of objects, places, faces, and colors. It may also be involved in face perception, and in the recognition of numbers and words.
The posterior cingulate cortex (PCC) is the caudal part of the cingulate cortex, located posterior to the anterior cingulate cortex. This is the upper part of the "limbic lobe". The cingulate cortex is made up of an area around the midline of the brain. Surrounding areas include the retrosplenial cortex and the precuneus.
The lingual gyrus, also known as the medialoccipitotemporal gyrus, is a brain structure that is linked to processing vision, especially related to letters. It is thought to also play a role in analysis of logical conditions and encoding visual memories. It is named after its shape, which is somewhat similar to a tongue. Contrary to the name, the region has little to do with speech.
Michael Hasselmo is an American neuroscientist and professor in the Department of Psychological and Brain Sciences at Boston University. He is the director of the Center for Systems Neuroscience and is editor-in-chief of Hippocampus (journal). Hasselmo studies oscillatory dynamics and neuromodulatory regulation in cortical mechanisms for memory guided behavior and spatial navigation using a combination of neurophysiological and behavioral experiments in conjunction with computational modeling. In addition to his peer-reviewed publications, Hasselmo wrote the book How We Remember: Brain Mechanisms of Episodic Memory.
The perirhinal cortex is a cortical region in the medial temporal lobe that is made up of Brodmann areas 35 and 36. It receives highly processed sensory information from all sensory regions, and is generally accepted to be an important region for memory. It is bordered caudally by postrhinal cortex or parahippocampal cortex and ventrally and medially by entorhinal cortex.
Retrospective memory is the memory of people, words, and events encountered or experienced in the past. It includes all other types of memory including episodic, semantic and procedural. It can be either implicit or explicit. In contrast, prospective memory involves remembering something or remembering to do something after a delay, such as buying groceries on the way home from work. However, it is very closely linked to retrospective memory, since certain aspects of retrospective memory are required for prospective memory.
Recognition memory, a subcategory of explicit memory, is the ability to recognize previously encountered events, objects, or people. When the previously experienced event is reexperienced, this environmental content is matched to stored memory representations, eliciting matching signals. As first established by psychology experiments in the 1970s, recognition memory for pictures is quite remarkable: humans can remember thousands of images at high accuracy after seeing each only once and only for a few seconds.
The relationship between sleep and memory has been studied since at least the early 19th century. Memory, the cognitive process of storing and retrieving past experiences, learning and recognition, is a product of brain plasticity, the structural changes within synapses that create associations between stimuli. Stimuli are encoded within milliseconds; however, the long-term maintenance of memories can take additional minutes, days, or even years to fully consolidate and become a stable memory that is accessible. Therefore, the formation of a specific memory occurs rapidly, but the evolution of a memory is often an ongoing process.
The hippocampus participates in the encoding, consolidation, and retrieval of memories. The hippocampus is located in the medial temporal lobe (subcortical), and is an infolding of the medial temporal cortex. The hippocampus plays an important role in the transfer of information from short-term memory to long-term memory during encoding and retrieval stages. These stages do not need to occur successively, but are, as studies seem to indicate, and they are broadly divided in the neuronal mechanisms that they require or even in the hippocampal areas that they seem to activate. According to Gazzaniga, "encoding is the processing of incoming information that creates memory traces to be stored." There are two steps to the encoding process: "acquisition" and "consolidation". During the acquisition process, stimuli are committed to short term memory. Then, consolidation is where the hippocampus along with other cortical structures stabilize an object within long term memory, which strengthens over time, and is a process for which a number of theories have arisen to explain the underlying mechanism. After encoding, the hippocampus is capable of going through the retrieval process. The retrieval process consists of accessing stored information; this allows learned behaviors to experience conscious depiction and execution. Encoding and retrieval are both affected by neurodegenerative and anxiety disorders and epilepsy.
The Ludwig-Boltzmann-Institute for functional Brain Topography was a research institute for the investigation of the function of brain areas. It was founded in 1993 in Vienna, Austria by Lüder Deecke. With his retirement in 2006 the institute was closed.
In psychology, associative memory is defined as the ability to learn and remember the relationship between unrelated items. This would include, for example, remembering the name of someone or the aroma of a particular perfume. This type of memory deals specifically with the relationship between these different objects or concepts. A normal associative memory task involves testing participants on their recall of pairs of unrelated items, such as face-name pairs. Associative memory is a declarative memory structure and episodically based.
Alexandra Golby is a professor of neurosurgery at Harvard Medical School and the Haley Distinguished Chair in the Neurosciences at Brigham and Women’s Hospital. She graduated from Yale University with a degree in physics and philosophy. She attended medical school at Stanford Medical School, where she also did her neurosurgery residency. She was awarded the Congress of Neurological Surgeons' Dandy Fellowship to study with Professor Alim Louis Benabid in Grenoble, France.
