Angular gyrus
Encyclopedia
The angular gyrus is a region of the brain
in the parietal lobe
, that lies near the superior edge of the temporal lobe
, and immediately posterior to the supramarginal gyrus
; it is involved in a number of processes related to language, mathematics and cognition. It is Brodmann area 39
of the human brain.
proposed that written word is translated to internal monologue via the angular gyrus.
V. S. Ramachandran
, director of the Center for Brain and Cognition at the University of California, San Diego
, directed a study that showed that the angular gyrus is at least partially responsible for understanding metaphor
s. Right-handed patients who had damage to their right angular gyrus, and whose speaking and comprehending English were seemingly unaffected, could not grasp the dual nature of metaphor. Given a common metaphorical phrase, each patient could give only a literal meaning. If pressed, they could invent a wild interpretation but it was well off the mark
In another exercise, the patients did not recognise a bulbous object as "bouba" and a jagged object as "kiki," whereas more than 90% of unaffected subjects did so in the test (See Bouba/kiki effect
). This showed an inability to connect visual stimuli to language.
The fact that the angular gyrus is proportionately much larger in hominids than other primates, and its strategic location at the crossroads of areas specialized for processing touch, hearing and vision, leads Ramachandran to believe that it is critical both to conceptual metaphors and to cross-modal abstractions more generally.
.
to the angular gyrus have been known to often cause arithmetic
deficits. Functional imaging
has shown that while other parts of the parietal lobe
bilaterally are involved in approximate calculations due to its link with spatiovisual abilities, the left angular gyrus together with left Inferior frontal gyrus
are involved in exact calculation due to verbal arithmetic fact retrieval and when this is greater, the greater a person's mathematical abilities.
Brain
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,...
in the parietal lobe
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
, that lies near the superior edge of 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....
, and immediately posterior to the supramarginal gyrus
Supramarginal gyrus
The supramarginal gyrus is a portion of the parietal lobe. It is probably involved with language perception and processing, and lesions in it may cause Wernicke's aphasia or transcortical sensory aphasia.-External links:...
; it is involved in a number of processes related to language, mathematics and cognition. It is Brodmann area 39
Brodmann area 39
Brodmann area 39, or BA39, is part of the parietal cortex in the human brain. BA39 encompasses the angular gyrus, lying near to the junction of temporal, occipital and parietal lobes....
of the human brain.
Language
GeschwindGeschwind
Geschwind, Geschwindt are surnames of:* Rudolf Geschwind * Norman Geschwind , father of modern behavioral neurology in America...
proposed that written word is translated to internal monologue via the angular gyrus.
V. S. Ramachandran
Vilayanur S. Ramachandran
Vilayanur Subramanian "Rama" Ramachandran, born 1951, is a neuroscientist known for his work in the fields of behavioral neurology and visual psychophysics...
, director of the Center for Brain and Cognition at the University of California, San Diego
University of California, San Diego
The University of California, San Diego, commonly known as UCSD or UC San Diego, is a public research university located in the La Jolla neighborhood of San Diego, California, United States...
, directed a study that showed that the angular gyrus is at least partially responsible for understanding metaphor
Metaphor
A metaphor is a literary figure of speech that uses an image, story or tangible thing to represent a less tangible thing or some intangible quality or idea; e.g., "Her eyes were glistening jewels." Metaphor may also be used for any rhetorical figures of speech that achieve their effects via...
s. Right-handed patients who had damage to their right angular gyrus, and whose speaking and comprehending English were seemingly unaffected, could not grasp the dual nature of metaphor. Given a common metaphorical phrase, each patient could give only a literal meaning. If pressed, they could invent a wild interpretation but it was well off the mark
In another exercise, the patients did not recognise a bulbous object as "bouba" and a jagged object as "kiki," whereas more than 90% of unaffected subjects did so in the test (See Bouba/kiki effect
Bouba/kiki effect
The Bouba/Kiki Effect is a non-arbitrary mapping between speech sounds and the visual shape of objects. This effect was first observed by German-American psychologist Wolfgang Köhler in 1929...
). This showed an inability to connect visual stimuli to language.
The fact that the angular gyrus is proportionately much larger in hominids than other primates, and its strategic location at the crossroads of areas specialized for processing touch, hearing and vision, leads Ramachandran to believe that it is critical both to conceptual metaphors and to cross-modal abstractions more generally.
Syndromes involving angular gyrus
Damage to the angular gyrus manifests as Gerstmann syndromeGerstmann syndrome
Gerstmann syndrome is a neurological disorder that is characterized by a constellation of symptoms that suggests the presence of a lesion in a particular area of the brain...
.
Out-of-body experiences
Recent experiments have demonstrated the possibility that stimulation of the angular gyrus is the cause of out-of-body experiences. Stimulation of the angular gyrus in one experiment caused a woman to perceive a phantom existence behind her. Another such experiment gave the test subject the sensation of being on the ceiling. This is attributed to a discrepancy in the actual position of the body, and the mind's perceived location of the body.Mathematics
Since 1919, brain injuriesAcquired brain injury
An acquired brain injury is brain damage caused by events after birth, rather than as part of a genetic or congenital disorder such as fetal alcohol syndrome, perinatal illness or perinatal hypoxia. ABI can result in cognitive, physical, emotional, or behavioural impairments that lead to permanent...
to the angular gyrus have been known to often cause arithmetic
Arithmetic
Arithmetic or arithmetics is the oldest and most elementary branch of mathematics, used by almost everyone, for tasks ranging from simple day-to-day counting to advanced science and business calculations. It involves the study of quantity, especially as the result of combining numbers...
deficits. Functional imaging
Functional imaging
Functional imaging , is a method of detecting or measuring changes in metabolism, blood flow, regional chemical composition, and absorption....
has shown that while other parts of the parietal lobe
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
bilaterally are involved in approximate calculations due to its link with spatiovisual abilities, the left angular gyrus together with left Inferior frontal gyrus
Inferior frontal gyrus
The inferior frontal gyrus is a gyrus of the frontal lobe . It is labelled gyrus frontalis inferior, its Latin name...
are involved in exact calculation due to verbal arithmetic fact retrieval and when this is greater, the greater a person's mathematical abilities.
External links
- NIF Search - Angular Gyrus via the Neuroscience Information FrameworkNeuroscience Information FrameworkThe Neuroscience Information Framework is a repository of global neuroscience web resources, including experimental, clinical, and translational neuroscience databases, knowledge bases, atlases, and genetic/genomic resources.-Description:...