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What part of the brain controls writing?

Handwriting runs on a network: Exner’s area at the back of the left middle frontal gyrus is proposed to turn a word’s spelling into the movements that write it, the precentral gyrus moves the hand, the superior parietal lobule and the cerebellum steer it, and the left fusiform gyrus helps recall how the word is spelled. [1]

The 3D brain needs JavaScript. The list of parts still says what each one does for writing.

Lit: whole parts; region borders not drawn.

Slice

All 6 parts are lit together. Drag to turn, pinch or scroll to zoom, tap a part on the brain or a name in the list to focus it; .

Exner’s area is a region on the middle frontal gyrus, not a separate shape. The 3D model has no shape for it, so the whole middle frontal gyrus is lit; the region’s exact border is not drawn.

Writing: 6 parts lit

Middle frontal gyrus, superior parietal lobule, precentral gyrus, cerebellum, angular gyrus and fusiform gyrus. Tap one to see where it is and what it does.

The parts and their roles

The back of the left middle frontal gyrus holds Exner’s area (below), proposed to link a word’s spelling to the motor programs that write it. In a 53-adult fMRI study of copying characters by hand it was the region whose activity differed between men and women, and it worked together with the right cerebellum. [1][2] Where is the middle frontal gyrus?
With the intraparietal sulcus beneath it, believed to support the sensorimotor control of handwriting; it receives a great deal of visual input and sensory input from the hand. [1][3] Where is the superior parietal lobule?
The primary motor cortex, mapped from leg near the midline to face at the side, with the arm and hand in between; writing characters, compared with drawing symbols, activated it in the 53-adult study. [4][1] Where is the motor cortex (precentral gyrus)?
Believed to support the sensorimotor control of handwriting, its activity during writing leaning to the right side. In 73 adults, the wiring of the pathway from the cerebellum through the thalamus to the cortex tracked how accurately they spelled words to dictation, beyond its part in spoken production. [1][5] Where is the cerebellum?
Associated with complex language functions: reading, writing and interpreting what is written. Brownsett and Wise highlight the left angular gyrus in both speaking and writing, and Norman Geschwind proposed that it translates written words into inner speech. [6] Where is the angular gyrus?
The left inferior temporal cortex including the mid-fusiform gyrus is thought to support retrieving a word’s spelling while writing it; it holds the visual word form area that reading uses. [1][7] Where is the fusiform gyrus?

Named areas on the lit gyri

Exner’s area, on the : The posterior part of the left middle frontal gyrus (around Brodmann area 6, in the premotor cortex), proposed to convert between spelling and the movements that form letters. It is one of the main writing centres of the brain and is also active during reading. [1][8]

How they work together

Studies split writing into central steps, recalling how a word is spelled, and peripheral ones, turning the letters into pen movements. Imaging ties the first more to the left fusiform gyrus and the second to Exner’s area, the superior parietal lobule and the cerebellum. [1][5]
In the 53-adult study, writing Chinese characters compared with drawing symbols lit a wide network: the precentral and postcentral gyri, the superior, middle and inferior frontal gyri, the superior and middle temporal gyri, the fusiform gyrus and the cerebellum. [1]
Activity was lopsided: Exner’s area and the superior parietal lobule leaned left in men, and the cerebellum leaned right in both men and women, whichever characters were written. [1]
Honest limit: these are networks seen in brain imaging, not single centres. Exner’s area has no drawn border, and most of this map comes from a few tasks (copying characters, spelling to dictation) in young adults, so other scripts and tasks may differ. [1][5]

Reading and writing share parts: the angular gyrus and the fusiform gyrus with its visual word form area are lit on both pages, and Exner’s area, one of the main writing centres, is also active during reading. [8][6] What part of the brain is used for reading?

Writing a digit is wired differently from writing a letter: tractography in healthy adults found fronto-parietal fibres (the superior longitudinal fascicle) linking the upper part of Exner’s area with the intraparietal sulcus used for numbers, while language pathways reach its lower part. [9] What part of the brain handles numbers and maths?

Sources

Facts describe anatomy and normal function only. A part lit here takes part in writing; it does not do it alone, and it does other jobs too. The 3D model is the adult male BodyParts3D brain (credits and licence); on it the brainstem includes the midbrain, pons and medulla, so lighting the brainstem lights all three.