Spindle rotation is a structure of the brain, in the form of a convolution, Involved in different processes related to visual processing, understanding the meaning of written text or recognizing faces, among other functions.
As we will see later, damage to this structure causes severe sensory perceptions.
In this article, we tell you what spindle rotation is, its location and structure, functions and main areas, and the most common disorders related to damage to this brain structure.
What is the spindle rotation?
Spindle rotation is a convolution of the brain that is part of the temporal lobe and the occipital lobe involved in aspects such as visual recognition of words and faces or identifying categories.
This convolution was first described in 1854 by anatomist Emil Huschke, Who labeled this structure with this name because it was wider in the middle than at its ends, with a spindle-like shape.
It should be noted that the cerebral cortex contains many convolutions and furrows which give this wrinkled appearance so characteristic of this organ and which we all know. These folds increase the total surface area of the brain, so that more neural nuclei can be grouped together and therefore also increase the ability to process information.
Location and structure
At the neuroanatomical level, the fusiform gyrus is one of the largest structures inserted in the ventral temporal cortex. This cerebral gyrus is located on the basal surface of the temporal and occipital lobes, between the parahippocampal gyrus and the lingual gyrus (medially) and the inferior temporal gyrus (laterally). .
The fusiform gyrus consists of two parts: an anterior temporal part and a posterior occipital part. The foremost part of its temporal part is near the cerebral peduncles and is usually curved or pointed, while the occipital part is below the lingual gyrus.
The collateral groove separates the fusiform turn from the parahippocampal turn and the occipitotemporal groove separates it from the inferior temporal turn. It should be noted that the spindle rotation is part of the Brodmann zone 37, along with the inferior and medial temporal gyrus.
Brodmann’s zones classify different parts of the cerebral cortex according to their involvement in different cognitive and behavioral functions, forming a topographic map of the brain that helps professionals in the field of neuroscience better understand the functioning of each brain structure.
The main function of the spindle rotation involves the processing of visual information, Including the identification and differentiation of objects. In addition to high-level visual processing, this brain structure participates in cognitive processes such as memory, multisensory integration or perception.
In terms of language, this area of the brain is involved in aspects such as semantic categorization, word search and generation, understanding metaphors or the connection between spelling and phonological components; at the level of memory processing, it participates in the recognition of true and false memories, as well as in spontaneous coding.
It is also believed that the rotation of the spindle could have a close functional relationship with the angular rotation, as this structure is involved in the processing of colors. The fusiform rotation communicates with the visual trajectory and the angular rotation, which allows the association of colors and shapes.
On the other hand, although the exact functional relevance of spindle rotation remains uncertain, it has been suggested that it may be involved in the following neurological systems related to the processing and recognition of visual information:
Identification of characteristics within categories
The fusiform zone of the faces
The fusiform area of the faces is perhaps the most well-known structure in this region of the brain. It is located on the side surface of half of the spindle-shaped gyrus and plays a key role in face identification, including face recognition.
Currently, there is an open debate in the neuroscientific community as to whether this region is only dedicated to facial treatment or if it is also involved in the recognition of other objects. One hypothesis (known as the experimental hypothesis) suggests that this region would be important for discriminating and individualizing visually similar objects. For example, when a chess expert identifies a pawn or a queen.
One of the controversies around this region stems from the observation that this area does not fully develop until adolescence, although babies already show some ability to differentiate faces, like that of their mothers, and a preference for female faces. MRI studies have also not confirmed that this area participates in these functions.
However, spindle rotation and the spindle-shaped area of faces are not the only brain region that makes it easier to identify faces. Although the fusiform area of the faces is an important component, it requires a network of different neural nuclei in the cortex that can recognize faces, including areas adjacent to the occipital lobe (the main area responsible for visual processing).
One of the most well-known disorders related to spindle-shaped damage is prosopagnosia or visual blindness, a condition characterized by the inability to recognize familiar faces (even one’s own). This disorder may be the result of isolated lesions in the spindle-shaped area of the faces of the spindle-shaped gyrus.
Other functions involved in visual processing, such as word processing, are known to remain intact in patients with prosopagnosia; when acquired, it usually results from lesion of the fusiform gyrus and usually occurs in adults, whereas in congenital prosopagnosia, the subject never develops the ability to recognize faces.
Another condition that can be caused by damage to structures related to spindle rotation is synesthesia, a neurological condition that causes stimulation of one sensory pathway to generate an involuntary experience in another equally sensory pathway; for example, seeing colors when certain sounds are heard.
The most common subtypes of synesthesia include: color grapheme, which involves associating a sign or letter with a given color; and color music, when the individual sees different colors depending on the type of music he is listening to.
Finally, dyslexia, a disorder that causes confusion and impaired reading accuracy and fluency, is another condition related to lower gray matter activation and density.
McCarthy, G., Puce, A., Gore, JC and Allison, T. (1997). Specific treatment of the face during the rotation of the human spindle. Journal of Cognitive Neuroscience, 9 (5), 605-610.
Snell, RS (2007). Clinical neuroanatomy. Pan American Medical Ed.