Spatial view cells are

neuron A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...

s in

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

hippocampus The hippocampus (via Latin from Greek , '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, a ...

; they respond when a certain part of the environment is in the animal's

field of view The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. Humans a ...

. They are related to

place cells A place cell is a kind of pyramidal neuron in the hippocampus that becomes active when an animal enters a particular place in its environment, which is known as the place field. Place cells are thought to act collectively as a cognitive represe ...

and

head direction cells Head direction (HD) cells are neurons found in a number of brain regions that increase their firing rates above baseline levels only when the animal's head points in a specific direction. They have been reported in rats, monkeys, mice, chinchillas a ...

. Spatial view cells differ from

, since they are not localized in space. They also differ from

since they don't represent a global orientation (like a

compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...

), but the direction towards a specific object. Spatial view cells are the

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

s that respond in the

when a particular location is being recalled. These cells are identified in the

of test subjects by monitoring individual neurons while the test subject is moved around in a cue controlled spatial environment. The spatial view cells are the cells that fire consistently when the

monkey Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomple ...

is looking at a certain direction in the environment; this is independent of the head direction or the location of the monkey. Also, these cells are confirmed to be spatial view cells by observing that there is minimal randomized firing of the cells without the appropriate

stimulus A stimulus is something that causes a physiological response. It may refer to: *Stimulation **Stimulus (physiology), something external that influences an activity **Stimulus (psychology), a concept in behaviorism and perception *Stimulus (economi ...

present.

Characteristics

Spatial view cells can be characterized by the following features: * respond to a region of visual space being looked at, relatively independently of where the

is located * respond to a small number of visual cues generally within a 30°

receptive field The receptive field, or sensory space, is a delimited medium where some physiological stimuli can evoke a sensory neuronal response in specific organisms. Complexity of the receptive field ranges from the unidimensional chemical structure of od ...

* activated when doing spatial tasks which include active walking in a spatial environment * fire relatively independent of the place where the

is located * represent the place at which the

is looking * generally stimulated by at least 3 cues present in optimal view * fire uniformly all over different areas in space as long as

is looking at the same area * ability to maintain their spatial properties for periods of up to several minutes in the dark * responses depend on where the

is looking, by measuring eye position * spatial representation is

allocentric Allocentrism is a collectivistic personality attribute whereby people center their attention and actions on other people rather than themselves. It is a psychological dimension which corresponds to the general cultural dimension of collectivism. ...

* responses still occur in some cases even if view details are obscured with

curtain A curtain is a piece of cloth or other material intended to block or obscure light, air drafts, or (in the case of a shower curtain), water. A curtain is also the movable screen or drape in a theatre that separates the stage from the auditorium ...

s The spatial view cells that respond in the absence of visual cues are generally found in the

Cornu Ammonis area 1 The hippocampus proper refers to the actual structure of the hippocampus which is made up of three regions or subfields. The subfields CA1, CA2, and CA3 use the initials of cornu Ammonis, an earlier name of the hippocampus. Structure There are ...

, the

parahippocampal gyrus The parahippocampal gyrus (or hippocampal 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 inv ...

, and the presubiculum, while the ones that do not respond are found in the

Cornu Ammonis region 3 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 mythol ...

. The cells found in the CA1,

, and presubiculum regions often provide a longer response even after the

is removed for up to several minutes in complete

darkness Darkness, the direct opposite of lightness, is defined as a lack of illumination, an absence of visible light, or a surface that absorbs light, such as black or brown. Human vision is unable to distinguish colors in conditions of very low lu ...

. Spatial view cells update their representations by the use of

idiothetic Idiothetic literally means "self-proposition" (Greek derivation), and is used in navigation models (e.g., of a rat in a maze) to describe the use of self-motion cues, rather than allothetic, or external, cues such as landmarks, to determine posit ...

inputs in the dark and these cells are commonly found in the CA1,

, and presubiculum regions.

Uses

Spatial view cells are used by

primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

for storing an

episodic memory Episodic memory is the memory of everyday events (such as times, location geography, associated emotions, and other contextual information) that can be explicitly stated or conjured. It is the collection of past personal experiences that occurred ...

that helps with remembering where a particular object was in the environment. Imaging studies have shown that the hippocampus plays an important role in spatial navigation and episodic memories. Also, spatial view cells enable them to recall locations of objects even if they are not physically present in the environment. The

neurons A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...

associated with remembering the location and object are often found in the

. These spatial view cells do not only recall specific locations, but they also remember

distances Distance is a numerical or occasionally qualitative measurement of how far apart objects or points are. In physics or everyday usage, distance may refer to a physical length or an estimation based on other criteria (e.g. "two counties over"). ...

between other

landmarks A landmark is a recognizable natural or artificial feature used for navigation, a feature that stands out from its near environment and is often visible from long distances. In modern use, the term can also be applied to smaller structures or f ...

around the place in order to gain a better understanding of where the places are spatially. In real world applications,

monkeys Monkey is a common name that may refer to most mammals of the infraorder Simiiformes, also known as the simians. Traditionally, all animals in the group now known as simians are counted as monkeys except the apes, which constitutes an incomple ...

remember where they saw ripe

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

with the aid of spatial view cells.

Humans Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

use spatial view cells when they try to recall where they may have seen a person or where they left their keys. Primates' highly developed visual and

eye movement Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of interests. ...

control systems enables them to explore and remember information about what's present at places in the environment without having to physically visit those places. These sorts of

memories Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...

would be useful for spatial

navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, ...

in which the

visualize everything in an

, or worldly manner that allows them to convey directions to others without physically going through the entire route. These cells are used by primates in regular day-to-day lives.

Removal of spatial view cell

Diseases A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that ar ...

and

illnesses A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

that harm the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

and the

can also damage spatial view cells, which are located in the hippocampus.

Stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...

, and

encephalitis Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...

are only a few of the various illnesses that can cause harm to the spatial view cells. Some clinical

symptoms Signs and symptoms are the observed or detectable signs, and experienced symptoms of an disease, illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormali ...

present in

patients A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health c ...

with damage to the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...

include:

fever Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...

altered mental status An altered level of consciousness is any measure of arousal other than normal. Level of consciousness (LOC) is a measurement of a person's arousability and responsiveness to stimuli from the environment. A mildly depressed level of consciousne ...

, and

neck stiffness Neck stiffness, stiff neck and nuchal rigidity are terms often used interchangeably to describe the medical condition when one experiences discomfort or pain when trying to turn, move, or flex the neck. Possible causes include muscle strain or spr ...

Lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classifi ...

studies have shown that damage to the hippocampus or to some of its connections, such as the fornix, in monkeys produces deficits in

learning Learning is the process of acquiring new understanding, knowledge, behaviors, skills, value (personal and cultural), values, attitudes, and preferences. The ability to learn is possessed by humans, animals, and some machine learning, machines ...

about the places of objects and about the places where responses should be made. This sort of damage to the brain often results in impaired object-place memory. Object-place memory tasks require the monkey to not only remember the object seen, but they must also remember where the object was seen in the environment. It has been shown that posterior para-hippocampal lesions in

macaques The macaques () constitute a genus (''Macaca'') of sociality, gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit species distribution, ranges throughout Asia, North Africa, and (in barbary macaques ...

impair even a simple type of object-place learning in which only one pair of unique stimuli are needed for memory.

Relationship to other diseases

Patients A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health c ...

with damage to spatial view cells will often show similar symptoms from other

diseases A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that ar ...

such as: vascular dementia,

Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...

, amnesia fugue,

macular degeneration Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred or no vision in the center of the visual field. Early on there are often no symptoms. Over time, however, som ...

, and optic nerve damage.Dr. Manish N. Patel, Resident Physician at St. Vincent's Medical Center Department of Family Medicine. Interview date October 19th, 2010. Another illness that reflects signs of spatial view damage is fornix lesions that impair conditional left–right discrimination learning. Patients with damage to the

temporal lobe The temporal lobe is one of the four Lobes of the brain, 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 temporal lobe ...

which also includes the

can sometimes have

Amnesia Amnesia is a deficit in memory caused by brain damage or disease,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be caused temporarily by the use ...

. Patients with amnesia often have memory impairments in which they have difficulty remembering both what they saw and where they saw the object or event take place. These signs point to the possible damage to spatial view cells found in the hippocampus.

Current research involving spatial view cells

Optimal firing rate

Current research shows that the maximum firing rate of spatial view cells is obtained when the test agent is allowed to explore the environment freely. Tests in which the

was not allowed to have active locomotion provided very few results of spatial view cells being detected in the

. Majority of the

experiment An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into Causality, cause-and-effect by demonstrating what outcome oc ...

s conducted for spatial view cells involved the use of

macaque The macaques () constitute a genus (''Macaca'') of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and (in one instance) Gibraltar. Macaques are principally ...

as test subjects. These types of cells are identified by monitoring the hippocampus of the monkeys while the brains are stimulated by presenting various images and objects in the monkey's vision. Various researchers use different

methodologies In its most common sense, methodology is the study of research methods. However, the term can also refer to the methods themselves or to the philosophical discussion of associated background assumptions. A method is a structured procedure for bri ...

in sync with the experiment being conducted in order to identify these spatial view cells. For example, in a delayed spatial response task, the monkey is shown a stimulus on one side of a screen and then the stimulus is taken away. After a short while, the stimulus is again presented to the monkey in the same location and the firing of the cell in the hippocampus that is specifically associated with the location at which the monkey is looking and is independent of the location of the monkey helps identify the spatial view cell. The monkeys in this of experiment are encouraged by rewarding them with

fruit juice Juice is a drink made from the extraction or pressing of the natural liquid contained in fruit and vegetables. It can also refer to liquids that are flavored with concentrate or other biological food sources, such as meat or seafood, such as ...

when they correctly identify the same object in the same location twice in a row and if they get it incorrect, the monkeys receive a saline taste.

Association with episodic memories

The experiments often use object-place memory tasks because they are representative of

episodic memories Episodic memory is the memory of everyday events (such as times, location geography, associated emotions, and other contextual information) that can be explicitly stated or conjured. It is the collection of past personal experiences that occurred ...

and often employ similar parts of the

. It is also believed that whenever an episodic memory is stored, part of the context from that event is also stored along with it. As a result, recalling a certain place can link up the

emotions Emotions are mental states brought on by neurophysiological changes, variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. There is currently no scientific consensus on a definition. ...

at that time. These recollections do not only happen if a place is recalled, but they are prone to occur if the person is in the same mood as they were at the time of the event. Rewards are also remembered along with the place at which it was received. Spatial view cells have been proven to be independent of head direction and place cells. Spatial view cells have been shown to respond even in the dark without any visual cues as long as the test subject was facing in the proper direction. It is believed that in the absence of visual cues, spatial view cells respond from the inputs being received from

and

along with eye position of the

. The use of the

vestibular system The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating movement with balance. Together with the cochlea, a part of the auditory system, it constitutes ...

and proprioceptive cues also provide a sense of direction the animal is facing in the dark.

Ability to update with new information

Research has led to the finding the spatial view cells are consistently updated with other inputs from the body. For example, when a monkey is oriented in a different position spatially such as being upside down, the spatial view cells still respond when the test subject faces the appropriate direction. This implies that there is stream of new information being received by the spatial view cells constantly. This integration from various inputs develops continuous attractor networks. Continuous attractor neural networks, also known as CANN, are routinely used when studying spatial view cells from an

stand point. CANNs allow researchers to closely monitor the associated

and

along with the spatial view cells as one close "packet of neural activity".

References

{{reflist Hippocampus (brain)