Gyrus
Published: Jul 17, 2023
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Updated: Jul 26, 2023
Written by Oseh Mathias
Founder, SpeechFit
A gyrus (plural: gyri) is a ridge or fold between two clefts (known as sulci) on the cerebral surface in the brain. These structures make up the intricate, folded landscape of the brain, giving it its characteristic wrinkled appearance[1].
The folding pattern of gyri and sulci increases the surface area of the brain, allowing for a higher number of neurons to reside within the limited volume of the skull. This increase in surface area is critical to cognitive functions as it allows for a greater degree of complexity in neural connections and functionalities.
Different gyri in the brain are involved in various cognitive processes, although it should be noted that no specific region works in isolation. The brain is an interconnected organ with specific regions functioning in symphony with other regions.
Some of the key gyri you may come across are listed below with their approximate Brodmann's area and their noted functions.
| English Name | Brodmann's Areas | Function |
|---|---|---|
| Precentral Gyrus | 4 | Primary Motor Cortex - responsible for the initiation of voluntary motor movement[2] |
| Postcentral Gyrus | 1, 2, 3 | Primary Somatosensory Cortex - primarily responsible for processing somatosensory information[3]. |
| Superior Temporal Gyrus | 41 and 42 (primary auditory cortex), 22 (part of Wernicke's area) | Involved in processing sound and is important for language comprehension[4] |
| Middle Temporal Gyrus | 21, 37 | Involved in semantic memory processing, language comprehension, and visual perception especially of faces and objects[5]. |
| Inferior Temporal Gyrus | 20 | Plays a role in visual object recognition[6]. |
| Cingulate Gyrus | 24, 32, 33 (anterior cingulate cortex), 23, 31 (posterior cingulate cortex) | Involved in processing emotions and behavior regulation. It also contributes to the regulation of autonomic motor function[7]. |
| Superior Frontal Gyrus | 6 (part of premotor and supplementary motor cortex), 8 (frontal eye fields), 9 | Involved in self-awareness, coordination of complex movements, and eye movements[8] |
| Middle Frontal Gyrus | 46 (part of the dorsolateral prefrontal cortex), 10 | Involved in executive functions such as working memory, planning, and problem solving[9]. |
| Inferior Frontal Gyrus | 44 and 45 (Broca's area) | Important for language production and speech[10]. |
| Fusiform Gyrus | 37 | Involved in high level visual processing and recognition (e.g., faces, body parts, word recognition)[11]. |
| Parahippocampal Gyrus | 27, 28, 34, 35, 36 | Critical for memory encoding and retrieval, particularly for spatial memory[12]. |
| Medial Orbital Gyrus | 10, 14 | Associated with reward-related decision-making and the expression of moods [13]. |
| Lateral Orbital Gyrus | 47, 12 | Involved in inhibitory control and impulse regulation [14]. |
| Anterior Orbital Gyrus | 11, 12 | Implicated in decision-making processes, including reward-based learning [15]. |
| Posterior Orbital Gyrus | 13, 14 | Plays a role in evaluating outcomes and adjusting behavior accordingly [16]. |
| Gyrus Rectus | 11, 12, 25 | Contributes to a range of functions including attention and social decisions [17]. |
| Angular Gyrus | 39 | Involved in language, number processing, spatial cognition, memory retrieval, attention, and theory of mind[18]. |
| Supramarginal Gyrus | 40 | Involved in language perception and processing, and is believed to be a part of the Wernicke's area[19]. |
| Lingual Gyrus | 18, 19 | Involved in processing vision, particularly related to letters and words. Also, contributes to dream visualization and encoding visual memories[20]. |
| Cuneus | 17, 18, 19 | Receives visual information from the contralateral superior retina. It's primarily involved in basic, preliminary visual processing[21]. |
| Lateral Occipital Gyrus | 18, 19 | Like much of the occipital lobe, these areas are involved in visual processing. They're particularly implicated in object recognition[22]. |
| Superior Occipital Gyrus | 18, 19 | While it has a role in visual processing, its function is not as well-defined as some of the other gyri[23]. |
| Middle Occipital Gyrus | 18, 19 | Participates in the visual processing, particularly the recognition of shapes and objects[24]. |
Thus, gyri are not only an essential anatomical characteristic of the brain that allows for a larger number of neurons but they also demarcate regions that serve different cognitive functions.
Oseh is a software engineer, entrepreneur and founder of SpeechFit. Oseh is passionate about improving health and wellbeing outcomes for neurodiverse people and healthcare providers alike.
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