Difference between revisions of "Von Economo neuron"

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pyramidal and (b) the VENs stained with the Golgi method. Photomicrogaphs
 
pyramidal and (b) the VENs stained with the Golgi method. Photomicrogaphs
 
are montages taken of several planes and/or fields of view.
 
are montages taken of several planes and/or fields of view.
Scale bar applies to both images. [9]]]
+
Scale bar applies to both images. Source: [6]]]
 
== Basic information ==
 
== Basic information ==
[[Image:voneconomo.jpg|right|thumb|200px|Figure 2. Von Economo neuron compared to Pyramidal neuron [8]]]  
+
[[Image:voneconomo.jpg|right|thumb|200px|Figure 2. Von Economo neuron compared to Pyramidal neuron.  Source: [12]]]  
  
'''Spindle''' or '''Von Economo neurons (VENs)''' occur in primates (humans, gorillas, chimpanzees, bonobos, and orangutans), and while previously thought to be unique to the great apes, have more recently been found in cetaceans (humpback, fin, killer, and sperm whales).''
+
'''Spindle''' or '''Von Economo neurons (VENs)''' are bipolar neurons in the anterior cingulate, frontoinsular, and dorsoloteral prefrontal cortices of great apes (humans, gorillas, chimpanzees, bonobos, and orangutans), and while previously thought to be unique to the great apes, have more recently been found in cetaceans (humpback, fin, killer, and sperm whales) [8].  Because of their morphology and anatomical location, it has been speculated that VENs may play an important role in intuitive choice in social situations and that their dysfunction may be a factor in autism and Alzheimer's.  VENs were first described by Constantin Von Economo in 1925, and their exclusivity to the great apes was discovered by John Allman, Patrick Hof, and others, in 1999.''
  
 
'''Neuronal Type:''' Projection Neuron
 
'''Neuronal Type:''' Projection Neuron
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== Anatomy ==
 
== Anatomy ==
VENs are bipolar neurons with one large apical axon and a single basal dendrite.  They are found exclusively in layer Vb of the anterior cingulate cortex (ACC) and frontoinsular cortex (FI), and have also recently been identified in human dorsolateral prefrontal cortex (DLPFC) (Brodmann area 9). [7]
+
VENs are large, bipolar neurons with one large apical axon and a single basal dendrite.  They are found exclusively in layer Vb of the anterior cingulate cortex (ACC) and frontoinsular cortex (FI), and have also recently been identified in human dorsolateral prefrontal cortex (DLPFC) (Brodmann area 9). [9] Its large apical axon and high-volume, elongated soma is similar to that of the cortical pyramidal neuron, but the VEN lacks the pyramidal neuron's numerous basal dendrites, instead receiving inputs from a comparatively small subset of cortex; the average VEN is also 4.6 times larger
Its large apical axon and high-volume, elongated soma is similar to that of the fast-conducting, cortical pyramidal neuron, but the VEN lacks the pyramidal neuron's large array of basal dendrites and the average VEN is 4.6 times larger
+
than the average layer 5 pyramidal cell. [6]  Pyramidal neurons conduct information from the cortex to other parts of the central nervous system.  Their structural similarity to pyramidal neurons suggests that VENs may play a similar functional role, and because the speed at which neurons conduct information typically co-varies with the diameter of their axon, the large VENs may do so very quickly compared to other neurons. [5]  VENs are relatively rare, comprising 1-2% of the total neurons in layer 5 of the ACC. [2]  In FI, VENs are 30% more numerous in the right hemisphere than the left, a hempispherization that occurs in the first four years of postnatal development in humans. [5]
than the average layer 5 pyramidal cell. [4]  VENs are relatively rare, and thought to make up 1-2% of the Layer 5 neurons in ACC. [2]  In FI, VENs are 30% more numerous in the right hemisphere than the left. [6]
 
  
 
[[Image:locVEN.jpg|center|thumb|812px|Figure 3. Regions of the brain containing Von Economo neurons (VENs). (a) A lateral view of the brain, with fronto-insular cortex (FI) shown in red. (b) A medial view of the
 
[[Image:locVEN.jpg|center|thumb|812px|Figure 3. Regions of the brain containing Von Economo neurons (VENs). (a) A lateral view of the brain, with fronto-insular cortex (FI) shown in red. (b) A medial view of the
brain, with anterior cingulate cortex (ACC) shown in red. Adapted from Von Economo and Koskinas [1]. [6]]]
+
brain, with anterior cingulate cortex (ACC) shown in red. Adapted from Von Economo and Koskinas [1]. Source: [5]]]
  
 
== Molecular profile ==
 
== Molecular profile ==
* '''Neurotransmitter Receptors:''' vasopressin 1a, dopamine d3, serotonin 2b [6]
+
* '''Neurotransmitter Receptors:''' vasopressin 1a, dopamine d3, serotonin 2b [5]
 
 
== Physiology ==
 
  
 
== Synaptic Connections ==
 
== Synaptic Connections ==
  
 
Though currently unknown where VENs ultimately
 
Though currently unknown where VENs ultimately
project to, studies in monkeys indicate that ACC and FI
+
project to, ACC and FI connect to numerous anatomical areas: prefrontal, orbitofrontal, insular and anterior temporal cortices, amygdala, hypothalamus, and various thalamic nuclei. Allman and others have speculated that VENs project information processed in FI and ACC to other parts of the brain, including Brodmann's area 10, in frontopolar cortex. [11]
connect to a wide range of areas: prefrontal, orbitofrontal, insular and anterior
 
temporal cortices, amygdala, hypothalamus, and various
 
thalamic nuclei.  
 
  
 
== Ontogeny and Phylogeny ==
 
== Ontogeny and Phylogeny ==
  
[[Image:ven primates.jpg|right|thumb|600px|Figure 4. Primate cladogram detailing the species examined for VENs. Species in red have VENs in the FI. Pongids have VENs in the ACC only. [8]]]
+
[[Image:ven primates.jpg|right|thumb|600px|Figure 4. Primate cladogram detailing the species examined for VENs. Species in red have VENs in the FI. Pongids have VENs in the ACC only. Source: [12]]]
 +
 
 +
[[Image:VENmontage.jpg|thumb|812px|Figure 5. Von Economo neurons in layer Vb of the anterior cingulate cortex in human (A), bonobo (B), common chimpanzee (C), gorilla (D), and orangutan (E). In all of these species the VENs display similar morphology and apparent somatic size. Note the clusters of VENs in the through-focus photomontage from the human and in the bonobo, whereas isolated neurons are observed in the three other great apes. (F-H) No VENs are present in the anterior cingulate cortex of the white-handed gibbon (F), Patas monkey (G), or ring-tailed lemur (H). ''Bar = 50 µm (A), 80 µm (B-E and H), and 120 µm (F and G).''  Source: [3]]]
  
 
VENs develop late both ontogenetically and phylogenetically.
 
VENs develop late both ontogenetically and phylogenetically.
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Ontogenetically, VENs first appear in the 35th week
 
Ontogenetically, VENs first appear in the 35th week
 
of gestation; at birth only about 15% of the postnatal
 
of gestation; at birth only about 15% of the postnatal
number are present. The adult number is
+
number are present, and at 4 years old, the adult number are present. [5]
attained by 4 years of age. [6]
 
  
Analyses of over 30 mammalian species have failed to find VENs except in primates and cetaceans. Among primates, including the lesser apes (gibbons), VENs have only been observed in the great apes (humans, gorillas, chimpanzees, bonobos, and orangutans). [3]
+
Analyses of over 30 mammalian species have failed to find VENs except in primates and cetaceans. Among primates (including the lesser apes (gibbons)) VENs have only been found in the great apes (humans, gorillas, chimpanzees, bonobos, and orangutans). [3]
  
Among hominids, humans have the most VENs, both in terms of absolute number and relative percentage compared to total number of neurons. In decreasing order of total number of VENs, they are found in humans, bonobos, chimpanzees, gorillas, and orangutans. In humans and bonobos, VENs are distributed in clusters of 3-6 neurons, while in other apes they show no such pattern of distribution. In analyses of total number of VENs present in FI of both hemispheres, the average adult human was found to have 193,000 cells, a 4 year old human child had 184,000, the average human newborn had 28,200, a gorilla had 16,710, a bonobo had 2,159, and a chimpanzee had 1,808. [3,4]
+
Among the great apes, humans have the most VENs, both in terms of absolute number and relative percentage compared to total number of neurons. In decreasing order of total number, VENs are found in humans, bonobos, chimpanzees, gorillas, and orangutans. Unlike in the other species exhibiting them, VENs in humans and bonobos are distributed in clusters of 3-6 neurons. In analyses of total number of VENs present in FI of both hemispheres, the average adult human was found to have 193,000 cells, a 4 year old human child had 184,000, the average human newborn had 28,200, a gorilla had 16,710, a bonobo had 2,159, and a chimpanzee had 1,808. [3,4]
  
[[Image:VENmontage.jpg|thumb|812px|Figure 5. Von Economo neurons in layer Vb of the anterior cingulate cortex in human (A), bonobo (B), common chimpanzee (C), gorilla (D), and orangutan (E). In all of these species the VENs display similar morphology and apparent somatic size. Note the clusters of VENs in the through-focus photomontage from the human and in the bonobo, whereas isolated neurons are observed in the three other great apes. (F-H) No VENs are present in the anterior cingulate cortex of the white-handed gibbon (F), Patas monkey (G), or ring-tailed lemur (H). ''Bar = 50 µm (A), 80 µm (B-E and H), and 120 µm (F and G).'' [3]]]
+
That their relative abundance and clustering in species co-varies with a species' phylogenetic proximity to humans has led to speculation that VENs are important to evolution and cognition.  That they occur in hominids and pongids (but no other primates) suggests that VENs evolved relatively recently: approximately 15-20 million years ago, prior to the evolutionary divergence of orangutans and hominids. [3,4]  Their recent discovery in some whales suggests a second, independent evolution of VENs, though they may not have the same function in both apes and cetaceans [10].  
 
 
That their relative abundance and clustering in species co-varies with a species' phylogenetic proximity to humans has led to speculation that VENs are important to evolution and cognition.  That they occur in hominids and pongids (but no other primates) suggests that VENs evolved relatively recently: approximately 15-20 million years ago, prior to the evolutionary divergence of orangutans and hominids. [3,4]  Their recent discovery in some whales suggests a second, independent evolution of VENs in cetaceans. [11]  VENs may not have the same function in both sorts of organism, however. [10]
 
 
 
"The phylogeny of VENs make sense given their evolutionary context. The great apes are highly social animals that must engage in rapid decision-making to navigate complex social environs. Of the great apes, the most solitary is the orangutan. Similarly, they display the fewest VENs. Humans and bonobos have arguably the most complex social interactions, and display not only high numbers of VENs but also a similar clustered distribution, whereas in the common chimpanzee, gorilla, and orang, VENs are found in isolated arrangements." [8]
 
  
 
== Function and Behavior ==
 
== Function and Behavior ==
  
The FI and ACC, where VENs are located, have been implicated in social reasoning, emotion, and monitoring of visceral autonomic activity, among other functions. ACC projects to the frontopolar cortex, which has been implicated in cognitive dissonance and uncertainty.  Because of these purported functions in the areas in which VENs are located, and because their morphology suggests them as fast projection neurons, researchers have speculated that VENs have an important role to play in intuition, which allows us to overcome uncertainty, make quick decisions, and resolve cognitive dissonance. [6]
+
The FI and ACC, where VENs are located, are thought to be implicated in social reasoning, empathy, emotion, and monitoring of visceral autonomic activity, among other functions. ACC projects to the frontopolar cortex, which has been implicated in cognitive dissonance and uncertainty.  Because their morphology suggests them as fast-projection neurons, and because of the functions of the areas they are thought to receive information from and project information to, it is speculated that VENs have an important role to play in intuition, which allows one to overcome uncertainty, make quick decisions, and resolve cognitive dissonance. [5]
  
Because they evolved recently, VENs may be particularly susceptible to dysfunction.  Abnormal VEN development has been implicated in autism [6] and selective degeneration of VENs has been observed in Alzheimer's and dementia [12].
+
Abnormal VEN development has been  
 +
implicated in autism [5] and  
 +
selective degeneration of VENs has been observed in Alzheimer's and dementia [7].
  
 
== References ==
 
== References ==
Line 73: Line 66:
 
brain. Neuroscientist 8, 335–345
 
brain. Neuroscientist 8, 335–345
  
[5] Sherwood, C.C. et al. (2003) Evolution of specialized pyramidal
+
[5] Allman, J.M. et al. (2005) Intuition and autism: a possible role for
neurons in primate visual and motor cortex. Brain Behav. Evol. 61,
 
28–44
 
 
 
[6] Allman, J.M. et al. (2005) Intuition and autism: a possible role for
 
 
Von Economo neurons. TRENDS in Cognitive Sciences 9:8, 367-373
 
Von Economo neurons. TRENDS in Cognitive Sciences 9:8, 367-373
  
[7] Fajardo, C. et al. (2008) Von Economo neurons are present in the dorsolateral (dysgranular) prefrontal cortex of humans. Neuroscience Letters 435:3, 215-218
+
[6] Watson, K. K., et al. (2006) Dendritic architecture of the von Economo neurons. Neuroscience. 141:1107-1112
  
[8] http://neurotransponder.blogspot.com/2005/12/von-economo-neurons-intuition-and.html
+
[7] Seeley, W. W., et al. (2006) Early frontotemporal dementia targets neurons unique to apes and humans. Ann. Neurol. 60:6, 660-667
  
[9] Watson, K. K., et al. (2006) Dendritic architecture of the von Economo neurons. Neuroscience. 141:1107-1112.
+
[8] Hof, P. and Van Der Gucht, E. (2007) Structure of the cerebral cortex of the humpback whale, Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae). The Anatomical Record 290, 1-31
  
[10] Balter, M. (2006) Well-Wired Whales. ScienceNOW Daily News. November 27, 2006. http://sciencenow.sciencemag.org/cgi/content/full/2006/1127/1
+
[9] Fajardo, C. et al. (2008) Von Economo neurons are present in the dorsolateral (dysgranular) prefrontal cortex of humans. Neuroscience Letters 435:3, 215-218
  
[11] Hof, P. and Van Der Gucht, E. (2007) Structure of the cerebral cortex of the humpback whale, Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae). The Anatomical Record 290, 1-31
+
[10] Balter, M. (2006) Well-Wired Whales. ScienceNOW Daily News. November 27, 2006 http://sciencenow.sciencemag.org/cgi/content/full/2006/1127/1  
  
[12] Seeley, W. W., et al. (2006) Early frontotemporal dementia targets neurons unique to apes and humans. Ann. Neurol. 60(6):660-667.
+
[11] Balter, M. (2007) NEUROANATOMY: Brain Evolution Studies Go Micro. Science 315:5816, 1208 - 1211
 +
http://www.sciencemag.org/cgi/content/full/315/5816/1208
  
== Additional information ==
+
[12] http://neurotransponder.blogspot.com/2005/12/von-economo-neurons-intuition-and.html
[http://www.example.com| link title]
 
  
 
[[Category: User contributed neurons]]
 
[[Category: User contributed neurons]]

Revision as of 23:27, 26 August 2008

Figure 1. Photomicrographs of soma and proximal dendrites of (a) a pyramidal and (b) the VENs stained with the Golgi method. Photomicrogaphs are montages taken of several planes and/or fields of view. Scale bar applies to both images. Source: [6]

Basic information

Figure 2. Von Economo neuron compared to Pyramidal neuron. Source: [12]

Spindle or Von Economo neurons (VENs) are bipolar neurons in the anterior cingulate, frontoinsular, and dorsoloteral prefrontal cortices of great apes (humans, gorillas, chimpanzees, bonobos, and orangutans), and while previously thought to be unique to the great apes, have more recently been found in cetaceans (humpback, fin, killer, and sperm whales) [8]. Because of their morphology and anatomical location, it has been speculated that VENs may play an important role in intuitive choice in social situations and that their dysfunction may be a factor in autism and Alzheimer's. VENs were first described by Constantin Von Economo in 1925, and their exclusivity to the great apes was discovered by John Allman, Patrick Hof, and others, in 1999.

Neuronal Type: Projection Neuron


Anatomy

VENs are large, bipolar neurons with one large apical axon and a single basal dendrite. They are found exclusively in layer Vb of the anterior cingulate cortex (ACC) and frontoinsular cortex (FI), and have also recently been identified in human dorsolateral prefrontal cortex (DLPFC) (Brodmann area 9). [9] Its large apical axon and high-volume, elongated soma is similar to that of the cortical pyramidal neuron, but the VEN lacks the pyramidal neuron's numerous basal dendrites, instead receiving inputs from a comparatively small subset of cortex; the average VEN is also 4.6 times larger than the average layer 5 pyramidal cell. [6] Pyramidal neurons conduct information from the cortex to other parts of the central nervous system. Their structural similarity to pyramidal neurons suggests that VENs may play a similar functional role, and because the speed at which neurons conduct information typically co-varies with the diameter of their axon, the large VENs may do so very quickly compared to other neurons. [5] VENs are relatively rare, comprising 1-2% of the total neurons in layer 5 of the ACC. [2] In FI, VENs are 30% more numerous in the right hemisphere than the left, a hempispherization that occurs in the first four years of postnatal development in humans. [5]

Figure 3. Regions of the brain containing Von Economo neurons (VENs). (a) A lateral view of the brain, with fronto-insular cortex (FI) shown in red. (b) A medial view of the brain, with anterior cingulate cortex (ACC) shown in red. Adapted from Von Economo and Koskinas [1]. Source: [5]

Molecular profile

  • Neurotransmitter Receptors: vasopressin 1a, dopamine d3, serotonin 2b [5]

Synaptic Connections

Though currently unknown where VENs ultimately project to, ACC and FI connect to numerous anatomical areas: prefrontal, orbitofrontal, insular and anterior temporal cortices, amygdala, hypothalamus, and various thalamic nuclei. Allman and others have speculated that VENs project information processed in FI and ACC to other parts of the brain, including Brodmann's area 10, in frontopolar cortex. [11]

Ontogeny and Phylogeny

Figure 4. Primate cladogram detailing the species examined for VENs. Species in red have VENs in the FI. Pongids have VENs in the ACC only. Source: [12]
Figure 5. Von Economo neurons in layer Vb of the anterior cingulate cortex in human (A), bonobo (B), common chimpanzee (C), gorilla (D), and orangutan (E). In all of these species the VENs display similar morphology and apparent somatic size. Note the clusters of VENs in the through-focus photomontage from the human and in the bonobo, whereas isolated neurons are observed in the three other great apes. (F-H) No VENs are present in the anterior cingulate cortex of the white-handed gibbon (F), Patas monkey (G), or ring-tailed lemur (H). Bar = 50 µm (A), 80 µm (B-E and H), and 120 µm (F and G). Source: [3]

VENs develop late both ontogenetically and phylogenetically.

Ontogenetically, VENs first appear in the 35th week of gestation; at birth only about 15% of the postnatal number are present, and at 4 years old, the adult number are present. [5]

Analyses of over 30 mammalian species have failed to find VENs except in primates and cetaceans. Among primates (including the lesser apes (gibbons)) VENs have only been found in the great apes (humans, gorillas, chimpanzees, bonobos, and orangutans). [3]

Among the great apes, humans have the most VENs, both in terms of absolute number and relative percentage compared to total number of neurons. In decreasing order of total number, VENs are found in humans, bonobos, chimpanzees, gorillas, and orangutans. Unlike in the other species exhibiting them, VENs in humans and bonobos are distributed in clusters of 3-6 neurons. In analyses of total number of VENs present in FI of both hemispheres, the average adult human was found to have 193,000 cells, a 4 year old human child had 184,000, the average human newborn had 28,200, a gorilla had 16,710, a bonobo had 2,159, and a chimpanzee had 1,808. [3,4]

That their relative abundance and clustering in species co-varies with a species' phylogenetic proximity to humans has led to speculation that VENs are important to evolution and cognition. That they occur in hominids and pongids (but no other primates) suggests that VENs evolved relatively recently: approximately 15-20 million years ago, prior to the evolutionary divergence of orangutans and hominids. [3,4] Their recent discovery in some whales suggests a second, independent evolution of VENs, though they may not have the same function in both apes and cetaceans [10].

Function and Behavior

The FI and ACC, where VENs are located, are thought to be implicated in social reasoning, empathy, emotion, and monitoring of visceral autonomic activity, among other functions. ACC projects to the frontopolar cortex, which has been implicated in cognitive dissonance and uncertainty. Because their morphology suggests them as fast-projection neurons, and because of the functions of the areas they are thought to receive information from and project information to, it is speculated that VENs have an important role to play in intuition, which allows one to overcome uncertainty, make quick decisions, and resolve cognitive dissonance. [5]

Abnormal VEN development has been implicated in autism [5] and selective degeneration of VENs has been observed in Alzheimer's and dementia [7].

References

[1] Von Economo, C. and Koskinas, G. (1925) Die Cytoarchitectonik der Hirnrinde des erwachsenen Menschen, Springer

[2] Nimchinsky, E.A. et al. (1995) Spindle neurons of the human anterior cingulate cortex. J. Comp. Neurol. 355, 27–37

[3] Nimchinsky, E.A. et al. (1999) A neuronal morphologic type unique to humans and great apes. Proc. Natl. Acad. Sci. U. S. A. 96, 5268–5273

[4] Allman, J. et al. (2002) Two phylogenetic specializations in the human brain. Neuroscientist 8, 335–345

[5] Allman, J.M. et al. (2005) Intuition and autism: a possible role for Von Economo neurons. TRENDS in Cognitive Sciences 9:8, 367-373

[6] Watson, K. K., et al. (2006) Dendritic architecture of the von Economo neurons. Neuroscience. 141:1107-1112

[7] Seeley, W. W., et al. (2006) Early frontotemporal dementia targets neurons unique to apes and humans. Ann. Neurol. 60:6, 660-667

[8] Hof, P. and Van Der Gucht, E. (2007) Structure of the cerebral cortex of the humpback whale, Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae). The Anatomical Record 290, 1-31

[9] Fajardo, C. et al. (2008) Von Economo neurons are present in the dorsolateral (dysgranular) prefrontal cortex of humans. Neuroscience Letters 435:3, 215-218

[10] Balter, M. (2006) Well-Wired Whales. ScienceNOW Daily News. November 27, 2006 http://sciencenow.sciencemag.org/cgi/content/full/2006/1127/1

[11] Balter, M. (2007) NEUROANATOMY: Brain Evolution Studies Go Micro. Science 315:5816, 1208 - 1211 http://www.sciencemag.org/cgi/content/full/315/5816/1208

[12] http://neurotransponder.blogspot.com/2005/12/von-economo-neurons-intuition-and.html