Fusiform gyrus

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Fusiform gyrus
Gray727 fusiform gyrus.png
Medial surface of left cerebral hemisphere. (Fusiform gyrus shown in orange)
Medial surface of cerebral cortex - fusiform gyrus.png
Medial surface of right cerebral hemisphere. (Fusiform gyrus visible near bottom)
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Identifiers
Latin gyrus fusiformis
NeuroNames 139
NeuroLex ID birnlex_1641
TA98 A14.1.09.227
TA2 5500
FMA 61908
Anatomical terms of neuroanatomy

The fusiform gyrus, also known as the lateral occipitotemporal gyrus, [1] [2] is part of the temporal lobe and occipital lobe in Brodmann area 37. [3] The fusiform gyrus is located between the lingual gyrus and parahippocampal gyrus above, and the inferior temporal gyrus below. [4] Though the functionality of the fusiform gyrus is not fully understood, it has been linked with various neural pathways related to recognition. Additionally, it has been linked to various neurological phenomena such as synesthesia, dyslexia, and prosopagnosia.

Contents

Anatomy

Anatomically, the fusiform gyrus is the largest macro-anatomical structure within the ventral temporal cortex, which mainly includes structures involved in high-level vision. [5] [6] The term fusiform gyrus (lit. "spindle-shaped convolution") refers to the fact that the shape of the gyrus is wider at its centre than at its ends. This term is based on the description of the gyrus by Emil Huschke in 1854. [6] (see also section on history). The fusiform gyrus is situated at the basal surface of the temporal and occipital lobes and is delineated by the collateral sulcus (CoS) and occipitotemporal sulcus (OTS), respectively. [2] The OTS separates the fusiform gyrus from the inferior temporal gyrus (located laterally in respect to the fusiform gyrus) and the CoS separates the fusiform gyrus from the parahippocampal gyrus (located medially in respect to the fusiform gyrus).

The fusiform gyrus can be further delineated into a lateral and medial portion, as it is separated in its middle by the relatively shallow mid-fusiform sulcus (MFS). [7] [8] [9] Thus, the lateral fusiform gyrus is delineated by the OTS laterally and the MFS medially. Likewise, the medial fusiform gyrus is delineated by the MFS laterally and the CoS medially.

Importantly, the mid-fusiform sulcus serves as a macroanatomical landmark for the fusiform face area (FFA), a functional subregion of the fusiform gyrus assumed to play a key role in processing faces. [5] [10]

History

The fusiform gyrus has a contentious history that has recently been clarified. The term was first used in 1854 by Emil Huschke from Jena, Germany, who called the fusiform gyrus a "Spindelwulst" (lit. spindle bulge). He chose this term because of the similarity that the respective cerebral gyrus bears to the shape of a spindle, or fusil, due to its wider central section. [6] At first, researchers located the fusiform gyrus in other mammals as well, without taking into account the variations in gross organizations of other species' brains. Today, the fusiform gyrus is considered to be specific to hominoids. This is supported by research showing only three temporal gyri and no fusiform gyrus in macaques. [8]

The first accurate definition of the mid-fusiform sulcus was coined by Gustav Retzius in 1896. He was the first to describe the sulcus sagittalis gyri fusiformis (today: mid-fusiform sulcus), and correctly determined that a sulcus divides the fusiform gyrus into lateral and medial partitions. W. Julius Mickle mentioned the mid-fusiform sulcus in 1897 and attempted to clarify the relation between temporal sulci and the fusiform gyrus, calling it the "intra-gyral sulcus of the fusiform lobule". [6]

Function

The exact functionality of the fusiform gyrus is still disputed, but there is relative consensus on its involvement in the following pathways:

Processing of color information

In 2003, V. S. Ramachandran collaborated with scientists from the Salk Institute for Biological Studies in order to identify the potential role of the fusiform gyrus within the color processing pathway in the brain. Examining the relationship within the pathway specifically in cases of synesthesia, Ramachandran found that synesthetes on average have a higher density of fibers surrounding the angular gyrus. The angular gyrus is involved in higher processing of colors. [11] The fibers relay shape information from the fusiform gyrus to the angular gyrus in order to produce the association of colors and shapes in grapheme-color synesthesia. [11] Cross-activation between the angular and fusiform gyri has been observed in the average brain, implying that the fusiform gyrus regularly communicates with the visual pathway. [12]

Face and body recognition

Portions of the fusiform gyrus are critical for face and body recognition.

Word recognition

It is believed that portions of the left hemisphere fusiform gyrus are used in word recognition.

Within-category identification

Further research by MIT scientists showed that the left and right fusiform gyri played different roles, which subsequently interlinked. The left fusiform gyrus recognizes "face-like" features in objects that may or may not be actual faces, whereas the right fusiform gyrus determines if that recognized face-like feature is, in fact, a face. [13]

In a 2015 study, dopamine was proposed to play a key role in face recognition task and was considered to be related to neural activity in fusiform gyrus. By studying the correlation between the binding potential (BP) of dopamine D1 receptor by PET and blood-oxygen-level-dependent (BOLD) in fMRI scan during a face recognition task, higher availability of D1 receptor was shown to be associated with higher BOLD level. This study showed that this association with D1 BP is only significant for FFG, not other brain regions. The researchers also showed the possibility that higher availability of dopamine D1 receptor may underlie better performance in face recognition task. [14] Dopamine is known to be related to the reward system. The dopaminergic system shows an active response to stimuli that predict possible rewards. As a social demand, a face recognition task could be a cognition process that involves dopamine, which can elicit a reinforcement feedback. [14] [15]

A 2007 study investigated how dopamine may regulate FFG activity during a face recognition task. It indicated that BOLD activity can be modulated by dopamine's influence on postsynaptic D1 receptors. The regulation is achieved in a way that dopamine first influence post-synaptic potential, and then further cause BOLD activity increase in the local area. This link between post-synaptic BOLD activity increase and dopamine release can be explained by blockage of dopamine reuptake. [16]

Associated neurological phenomena

The fusiform gyrus has been speculated to be associated with various neurological phenomena.

Prosopagnosia

Some researchers think that the fusiform gyrus may be related to the disorder known as prosopagnosia, or face blindness. Research has also shown that the fusiform face area, the area within the fusiform gyrus, is heavily involved in face perception but only to any generic within-category identification that is shown to be one of the functions of the fusiform gyrus. [17] Abnormalities of the fusiform gyrus have also been linked to Williams syndrome. [18] Fusiform gyrus has also been involved in the perception of emotions in facial stimuli. [19] However, individuals with autism show little to no activation in the fusiform gyrus in response to seeing a human face. [20]

Synaesthesia

Recent research has seen activation of the fusiform gyrus during subjective grapheme–color perception in people with synaesthesia. [21] The effect of the fusiform gyrus in grapheme sense seems somewhat more clear as the fusiform gyrus seems to play a key role in word recognition. The connection to color may be due to cross wiring of (being directly connected to) areas of the fusiform gyrus and other areas of the visual cortex associated with experiencing color. [22]

Dyslexia

For those with dyslexia, it has been seen that the fusiform gyrus is underactivated and has reduced gray matter density. [23]

Face hallucinations

Increased neurophysiological activity in the fusiform face area may produce hallucinations of faces, whether realistic or cartoonesque, as seen in Charles Bonnet syndrome, hypnagogic hallucinations, peduncular hallucinations, or drug-induced hallucinations. [24]

Additional images

Related Research Articles

<span class="mw-page-title-main">Cingulate cortex</span> Part of the brain within the cerebral cortex

The cingulate cortex is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus. The cingulate cortex is usually considered part of the limbic lobe.

<span class="mw-page-title-main">Brodmann area</span> Region of the brain

A Brodmann area is a region of the cerebral cortex, in the human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of cells. The concept was first introduced by the German anatomist Korbinian Brodmann in the early 20th century. Brodmann mapped the human brain based on the varied cellular structure across the cortex and identified 52 distinct regions, which he numbered 1 to 52. These regions, or Brodmann areas, correspond with diverse functions including sensation, motor control, and cognition.

<span class="mw-page-title-main">Temporal lobe</span> One of the four lobes of the mammalian brain

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.

<span class="mw-page-title-main">Frontal lobe</span> Part of the brain

The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere. It is parted from the parietal lobe by a groove between tissues called the central sulcus and from the temporal lobe by a deeper groove called the lateral sulcus. The most anterior rounded part of the frontal lobe is known as the frontal pole, one of the three poles of the cerebrum.

<span class="mw-page-title-main">Brodmann area 37</span>

Brodmann area 37, or BA37, is part of the temporal cortex in the human brain. It contains the fusiform gyrus which in turn contains the fusiform face area, an area important for the recognition of faces.

<span class="mw-page-title-main">Gyrus</span> Ridge on the cerebral cortex of the brain

In neuroanatomy, a gyrus is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci. Gyri and sulci create the folded appearance of the brain in humans and other mammals.

<span class="mw-page-title-main">Parahippocampal gyrus</span> Grey matter region surrounding the hippocampus

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.

<span class="mw-page-title-main">Lobes of the brain</span> Parts of the cerebrum

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.

<span class="mw-page-title-main">Posterior cerebral artery</span> Artery which supplies blood to the occipital lobe of the brain

The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar artery, where it bifurcates into the left and right posterior cerebral arteries. These anastomose with the middle cerebral arteries and internal carotid arteries via the posterior communicating arteries.

<span class="mw-page-title-main">Brodmann areas 35 and 36</span>

Brodmann area 35, together with Brodmann area 36, comprise the perirhinal cortex. They are cytoarchitecturally defined temporal regions of the cerebral cortex.

<span class="mw-page-title-main">Middle temporal gyrus</span> One of three gyri of the temporal lobe of the brain

Middle temporal gyrus is a gyrus in the brain on the temporal lobe. It is located between the superior temporal gyrus and inferior temporal gyrus. It corresponds largely to Brodmann area 21.

<span class="mw-page-title-main">Inferior temporal gyrus</span> One of three gyri of the temporal lobe of the brain

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.

<span class="mw-page-title-main">Inferior parietal lobule</span> Portion of the parietal lobe of the brain

The inferior parietal lobule lies below the horizontal portion of the intraparietal sulcus, and behind the lower part of the postcentral sulcus. Also known as Geschwind's territory after Norman Geschwind, an American neurologist, who in the early 1960s recognised its importance. It is a part of the parietal lobe.

<span class="mw-page-title-main">Lingual gyrus</span> Gyrus of the occipital lobe of the brain

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.

<span class="mw-page-title-main">Sulcus (neuroanatomy)</span> Fold in the surface of the brain

In neuroanatomy, a sulcus is a depression or groove in the cerebral cortex. It surrounds a gyrus, creating the characteristic folded appearance of the brain in humans and other mammals. The larger sulci are usually called fissures.

<span class="mw-page-title-main">Superior longitudinal fasciculus</span> Association fiber tract of the brain

The superior longitudinal fasciculus (SLF) is an association tract in the brain that is composed of three separate components. It is present in both hemispheres and can be found lateral to the centrum semiovale and connects the frontal, occipital, parietal, and temporal lobes. This bundle of tracts (fasciculus) passes from the frontal lobe through the operculum to the posterior end of the lateral sulcus where they either radiate to and synapse on neurons in the occipital lobe, or turn downward and forward around the putamen and then radiate to and synapse on neurons in anterior portions of the temporal lobe.

Visual object recognition refers to the ability to identify the objects in view based on visual input. One important signature of visual object recognition is "object invariance", or the ability to identify objects across changes in the detailed context in which objects are viewed, including changes in illumination, object pose, and background context.

The mid-fusiform sulcus is a shallow sulcus that divides the fusiform gyrus into lateral and medial partitions. Functionally, the MFS divides both large-scale functional maps and identifies fine-scale functional regions such as the anterior portion of the fusiform face area.

<span class="mw-page-title-main">Occipital gyri</span> Three parallel gyri of the occipital lobe of the brain

The occipital gyri (OcG) are three gyri in parallel, along the lateral portion of the occipital lobe, also referred to as a composite structure in the brain. The gyri are the superior occipital gyrus, the middle occipital gyrus, and the inferior occipital gyrus, and these are also known as the occipital face area. The superior and inferior occipital sulci separates the three occipital gyri.

References

  1. ↑ Rajakumar, Raj; Kiernan, John (2014). BARR's The Human Nervous System (10 ed.). p. 219. ISBN   978-1-4511-7327-7.
  2. 1 2 "Gray's Anatomy – The Anatomical Basis of Clinical Practice 41st edition". 26 September 2015. Retrieved 18 November 2015.
  3. ↑ Nature Neuroscience, vol7, 2004
  4. ↑ "Gyrus". The free dictionary. Retrieved 2013-06-19.
  5. 1 2 Grill-Spector, Kalanit; Weiner, Kevin S. (2014). "The functional architecture of the ventral temporal cortex and its role in categorization". Nature Reviews Neuroscience. 15 (8): 536–548. doi:10.1038/nrn3747. PMC   4143420 . PMID   24962370.
  6. 1 2 3 4 Zilles, Weiner (2015). "The anatomical and functional specialization of the fusiform gyrus". Neuropsychologia. 83: 48–62. doi:10.1016/j.neuropsychologia.2015.06.033. PMC   4714959 . PMID   26119921.
  7. ↑ Grill-Spector, Weiner; et al. (2013). "The mid-fusiform sulcus: A landmark identifying both cyotarchitectonic and functional divisions of human ventral temporal cortex". NeuroImage. 84: 453–465. doi:10.1016/j.neuroimage.2013.08.068. PMC   3962787 . PMID   24021838.
  8. 1 2 Nasr (2011). "Scene-selective cortical regions in human and nonhuman primates". J Neurosci. 31 (39): 13771–85. doi:10.1523/jneurosci.2792-11.2011. PMC   3489186 . PMID   21957240.
  9. ↑ Grill-Spector, Weiner (2010). "Sparsely-distributed organization of face and limb activations in human ventral temporal cortex". NeuroImage. 52 (4): 1559–73. doi:10.1016/j.neuroimage.2010.04.262. PMC   3122128 . PMID   20457261.
  10. ↑ Grill-Spector, Weiner (2012). "The improbable simplicity of the fusiform face area". Trends in Cognitive Sciences. 16 (5): 251–254. doi:10.1016/j.tics.2012.03.003. PMID   22481071. S2CID   17376865.
  11. 1 2 Ramachandran, V.S. (January 17, 2011). The Tell Tale Brain . New York: W. W. Norton & Company, Inc. ISBN   978-0-393-34062-4.
  12. ↑ Hubbard EM, Ramachandran VS (November 2005). "Neurocognitive mechanisms of synesthesia". Neuron (Review). 48 (3): 509–20. doi: 10.1016/j.neuron.2005.10.012 . PMID   16269367.
  13. ↑ Trafton, A. "How does our brain know what is a face and what's not?" MIT News
  14. 1 2 Rypma, Bart; Fischer, Håkan; Rieckmann, Anna; Hubbard, Nicholas A.; Nyberg, Lars; Bäckman, Lars (2015-11-04). "Dopamine D1 Binding Potential Predicts Fusiform BOLD Activity during Face-Recognition Performance". The Journal of Neuroscience. 35 (44): 14702–14707. doi:10.1523/JNEUROSCI.1298-15.2015. ISSN   1529-2401. PMC   4635124 . PMID   26538642.
  15. ↑ Schultz, Wolfram (2007-05-01). "Behavioral dopamine signals". Trends in Neurosciences. 30 (5): 203–210. doi:10.1016/j.tins.2007.03.007. ISSN   0166-2236. PMID   17400301. S2CID   11965742.
  16. ↑ Knutson, Brian; Gibbs, Sasha E. B. (2007-02-06). "Linking nucleus accumbens dopamine and blood oxygenation". Psychopharmacology. 191 (3): 813–822. doi:10.1007/s00213-006-0686-7. ISSN   0033-3158. PMID   17279377. S2CID   2614688.
  17. ↑ McCarthy, G; et al. (1997). "Face-specific processing in the fuman fusform gyrus". Journal of Cognitive Neuroscience. 9 (5): 605–610. doi:10.1162/jocn.1997.9.5.605. hdl: 2022/22741 . PMID   23965119. S2CID   23333049.
  18. ↑ A. L. Reiss, et al. Preliminary Evidence Of Abnormal White Matter Related To The Fusiform Gyrus In Williams Syndrome: A Diffusion Tensor Imaging Tractography Study.Genes, Brain & Behavior 11.1, 62–68(2012)
  19. ↑ Radua, Joaquim; Phillips, Mary L.; Russell, Tamara; Lawrence, Natalia; Marshall, Nicolette; Kalidindi, Sridevi; El-Hage, Wissam; McDonald, Colm; Giampietro, Vincent (2010). "Neural response to specific components of fearful faces in healthy and schizophrenic adults". NeuroImage. 49 (1): 939–946. doi:10.1016/j.neuroimage.2009.08.030. PMID   19699306. S2CID   6209163.
  20. ↑ Carter, Rita. The Human Brain Book. p. 241.
  21. ↑ Imaging of connectivity in the synaesthetic brain
  22. ↑ Pujol, J. (2009-04-30). "Study data from J. Pujol and colleagues update understanding of life sciences". Science Letter.
  23. ↑ Clark, David (2005). The Brain and Behavior. Cambridge University Press. ISBN   978-0-521-54984-4.
  24. ↑ Jan Dirk Blom. A Dictionary of Hallucinations. Springer, 2010, p. 187. ISBN   978-1-4419-1222-0
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