Spatial view cells
Encyclopedia
Spatial view cells are neuron
s in primate
s' hippocampus
which fire when the animal
views a specific part of an environment. They respond when a certain part of the environment is in the animal's field of view
.
They are related to place cells and head direction cells
. Spatial view cells differ from place cells, since they are not localized in space. They also differ from head direction cells
since they don't represent a global orientation (like a compass
), but the direction towards a specific object. Spatial view cells are the cell
s that respond in the hippocampus
when a particular location is being recalled. These cells are identified in the hippocampus
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
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
present.
The spatial view cells that respond in the absence of visual cues are generally found in the Cornu Ammonis area 1, the parahippocampal gyrus
, and the presubiculum, while the ones that do not respond are found in the Cornu Ammonis region 3. The cells found in the CA1, parahippocampal gyrus
, and presubiculum regions often provide a longer response even after the stimulus
is removed for up to several minutes in complete darkness
. Spatial view cells update their representations by the use of idiothetic
inputs in the dark and these cells are commonly found in the CA1, parahippocampal gyrus
, and presubiculum regions.
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 associated with remembering the location and object are often found in the primate
hippocampus
. These spatial view cells do not only recall specific locations, but they also remember distances between other landmarks around the place in order to gain a better understanding of where the places are spatially.
In real world applications, monkeys remember where they saw ripe fruit
with the aid of spatial view cells. Humans 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 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 would be useful for spatial navigation
in which the primates visualize everything in an allocentric, 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.
and the hippocampus
can also damage spatial view cells, which are located in the hippocampus. Stroke
s, meningitis
, and encephalitis
are only a few of the various illnesses that can cause harm to the spatial view cells. Some clinical symptoms present in patients with damage to the central nervous system
include: fever
, altered mental status, and neck stiffness. Lesion
studies have shown that damage to the hippocampus or to some of its connections, such as the fornix, in monkeys produces deficits in learning
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 impair even a simple type of object-place learning in which only one pair of unique stimuli are needed for memory.
, Amnesia Fugue, Macular degeneration
, and optic nerve damage. 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
which also includes the hippocampus
can sometimes have Amnesia
. 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.
was not allowed to have active locomotion provided very few results of spatial view cells being detected in the hippocampus
. Majority of the experiments conducted for spatial view cells involved the use of macaque
monkeys 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 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 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.
. 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 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 head direction cells
and place cells along with eye position of the primate
. The use of the vestibular system
and proprioceptive cues also provide a sense of direction the animal is facing in the dark.
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 a idiothetic
stand point. CANNs allow researchers to closely monitor the associated head direction cells
and place cells along with the spatial view cells as one close "packet of neural activity".
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s in primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
s' hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
which fire when the animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
views a specific part of an environment. They respond when a certain part of the environment is in the animal's field of view
Field of view
The field of view is the extent of the observable world that is seen at any given moment....
.
They are related to place cells and head direction cells
Head direction cells
Many mammals possess neurons called head direction cells, which are active only when the animal's head points in a specific direction within an environment. These neurons fire at a steady rate Many mammals possess neurons called head direction (HD) cells, which are active only when the animal's...
. Spatial view cells differ from place cells, since they are not localized in space. They also differ from head direction cells
Head direction cells
Many mammals possess neurons called head direction cells, which are active only when the animal's head points in a specific direction within an environment. These neurons fire at a steady rate Many mammals possess neurons called head direction (HD) cells, which are active only when the animal's...
since they don't represent a global orientation (like a compass
Compass
A compass is a navigational instrument that shows directions in a frame of reference that is stationary relative to the surface of the earth. The frame of reference defines the four cardinal directions – north, south, east, and west. Intermediate directions are also defined...
), but the direction towards a specific object. Spatial view cells are the cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
s that respond in the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
when a particular location is being recalled. These cells are identified in the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
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
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
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
Stimulus (physiology)
In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....
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 monkeyMonkeyA monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
is located - respond to a small number of visual cues generally within a 30° receptive fieldReceptive fieldThe receptive field of a sensory neuron is a region of space in which the presence of a stimulus will alter the firing of that neuron. Receptive fields have been identified for neurons of the auditory system, the somatosensory system, and the visual system....
- activated when doing spatial tasks which include active walking in a spatial environment
- fire relatively independent of the place where the monkeyMonkeyA monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
is located - represent the place at which the monkeyMonkeyA monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
is looking - generally stimulated by at least 3 cues present in optimal view
- fire uniformly all over different areas in space as long as monkeyMonkeyA monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
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 monkeyMonkeyA monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
is looking, by measuring eye position - spatial representation is allocentric
- responses still occur in some cases even if view details are obscured with curtainCurtainA curtain is a piece of cloth intended to block or obscure light, or drafts, or water in the case of a shower curtain. Curtains hung over a doorway are known as portières...
s
The spatial view cells that respond in the absence of visual cues are generally found in the Cornu Ammonis area 1, the parahippocampal gyrus
Parahippocampal gyrus
The parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus. This region plays an important role in memory encoding and retrieval....
, and the presubiculum, while the ones that do not respond are found in the Cornu Ammonis region 3. The cells found in the CA1, parahippocampal gyrus
Parahippocampal gyrus
The parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus. This region plays an important role in memory encoding and retrieval....
, and presubiculum regions often provide a longer response even after the stimulus
Stimulus (physiology)
In physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....
is removed for up to several minutes in complete darkness
Darkness
Darkness, in contrast with brightness, is a relative absence of visible light. It is the appearance of black in a color space. When light is not present, rod and cone cells within the eye are not stimulated. This lack of stimulation means photoreceptor cells are unable to distinguish color...
. Spatial view cells update their representations by the use of idiothetic
Idiothetic
Idiothetic literally means "self-proposition" , and is used in navigation models as in the phrase "idiothetic cues" to indicate that path integration was used to determine the present location instead of allothetic, or external, cues...
inputs in the dark and these cells are commonly found in the CA1, parahippocampal gyrus
Parahippocampal gyrus
The parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus. This region plays an important role in memory encoding and retrieval....
, and presubiculum regions.
Uses
Spatial view cells are used by primates for storing an episodic memoryEpisodic memory
Episodic memory is the memory of autobiographical events that can be explicitly stated. Semantic and episodic memory together make up the category of declarative memory, which is one of the two major divisions in memory...
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 associated with remembering the location and object are often found in the primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
. These spatial view cells do not only recall specific locations, but they also remember distances between other landmarks around the place in order to gain a better understanding of where the places are spatially.
In real world applications, monkeys remember where they saw ripe fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
with the aid of spatial view cells. Humans 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 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 would be useful for spatial navigation
Navigation
Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...
in which the primates visualize everything in an allocentric, 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 and illnesses that harm the brainBrain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
and the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
can also damage spatial view cells, which are located in the hippocampus. Stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
s, meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
, and encephalitis
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
are only a few of the various illnesses that can cause harm to the spatial view cells. Some clinical symptoms present in patients with damage to the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
include: fever
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, altered mental status, and neck stiffness. Lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
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
Learning is acquiring new or modifying existing knowledge, behaviors, skills, values, or preferences and may involve synthesizing different types of information. The ability to learn is possessed by humans, animals and some machines. Progress over time tends to follow learning curves.Human learning...
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 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 with damage to spatial view cells will often show similar symptoms from other diseases such as: Vascular Dementia, Alzheimer's DiseaseAlzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
, Amnesia Fugue, Macular degeneration
Macular degeneration
Age-related macular degeneration is a medical condition which usually affects older adults and results in a loss of vision in the center of the visual field because of damage to the retina. It occurs in “dry” and “wet” forms. It is a major cause of blindness and visual impairment in older adults...
, and optic nerve damage. 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
Temporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
which also includes the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
can sometimes have Amnesia
Amnesia
Amnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...
. 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.
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 monkeyMonkey
A monkey is a primate, either an Old World monkey or a New World monkey. There are about 260 known living species of monkey. Many are arboreal, although there are species that live primarily on the ground, such as baboons. Monkeys are generally considered to be intelligent. Unlike apes, monkeys...
was not allowed to have active locomotion provided very few results of spatial view cells being detected in the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
. Majority of the experiments conducted for spatial view cells involved the use of macaque
Macaque
The macaques constitute a genus of Old World monkeys of the subfamily Cercopithecinae. - Description :Aside from humans , the macaques are the most widespread primate genus, ranging from Japan to Afghanistan and, in the case of the barbary macaque, to North Africa...
monkeys 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 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 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 and often employ similar parts of the brainBrain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
. 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 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 head direction cells
Head direction cells
Many mammals possess neurons called head direction cells, which are active only when the animal's head points in a specific direction within an environment. These neurons fire at a steady rate Many mammals possess neurons called head direction (HD) cells, which are active only when the animal's...
and place cells along with eye position of the primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
. The use of the vestibular system
Vestibular system
The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...
and proprioceptive cues also provide a sense of direction the animal is facing in the dark.
Ability to Update with New Information
ResearchResearch
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...
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 a idiothetic
Idiothetic
Idiothetic literally means "self-proposition" , and is used in navigation models as in the phrase "idiothetic cues" to indicate that path integration was used to determine the present location instead of allothetic, or external, cues...
stand point. CANNs allow researchers to closely monitor the associated head direction cells
Head direction cells
Many mammals possess neurons called head direction cells, which are active only when the animal's head points in a specific direction within an environment. These neurons fire at a steady rate Many mammals possess neurons called head direction (HD) cells, which are active only when the animal's...
and place cells along with the spatial view cells as one close "packet of neural activity".