The Neuroscience of Literacy: Key Brain Areas for Reading and Writing

 

The Neuroscience of Literacy: Key Brain Areas for Reading and Writing

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Organized by brain lobes — Predominantly left hemisphere

🧠  OCCIPITAL LOBE
Area (BA)	Functional name	Lobe / Location	Function relevant to reading and writing
BA 17 (V1 – Primary visual cortex)	Primary visual cortex (V1)	Occipital; posterior pole, calcarine sulcus	Initial processing of visual information: orientation, contrast, brightness, and letter edges. It is the cortical entry point for all visual information.
BA 18 (V2 – Prestriate cortex)	Secondary visual cortex (V2)	Occipital; surrounds V1	Analysis of contours, depth, and textures. Processes simple letter forms and sends them to higher-level areas.
BA 19 (V3–V5 – Extrastriate cortex)	Tertiary visual cortex (V3–V5)	Lateral and ventral occipital	Higher-order visual processing: motion (V5/MT), color, integration of letter-form information, grouping, and early orthographic analysis.
🧠  TEMPORAL LOBE
Area (BA)	Functional name	Lobe / Location	Function relevant to reading and writing
BA 20 (ITG – Inferior temporal gyrus)	Inferior temporal gyrus	Inferior temporal	Visual-semantic processing; recognition of objects and written words. Part of the ventral (“what”) pathway.
BA 21 (MTG – Middle temporal gyrus)	Middle temporal gyrus	Middle temporal	Semantic memory, meaning processing, lexical integration. Active during access to the mental lexicon.
BA 22 (Wernicke’s area)	Wernicke’s area	Left posterior superior temporal	Comprehension of spoken language; semantic-phonological processing; linkage between written form and meaning. Lesions produce Wernicke’s aphasia.
BA 37 (VWFA – Visual Word Form Area)	Fusiform gyrus / VWFA	Left inferior temporal	Automatic recognition of orthographic patterns: identifies words as complete visual units. Known as the brain’s “reading eye” (Cohen & Dehaene, 2000).
BA 38 (Temporal pole)	Temporal pole	Anterior tip of the temporal lobe	Multimodal semantic integration; retrieval of complex concepts; connection between verbal and nonverbal information.
🧠  PARIETAL LOBE
Area (BA)	Functional name	Lobe / Location	Function relevant to reading and writing
BA 5 (S2 – Associative somatosensory cortex)	Associative somatosensory cortex	Superior parietal	Sensorimotor integration; tactile and proprioceptive feedback during handwriting.
BA 7 (PPC – Posterior parietal cortex)	Superior parietal lobule / Precuneus	Superior parietal	Visuospatial attention; planning of graphomotor movements; eye–hand coordination in writing.
BA 39 (AG – Angular gyrus)	Angular gyrus	Left inferior parietal	Multimodal hub: integrates visual, phonological, and semantic information. Essential for reading comprehension and access to the orthographic lexicon.
BA 40 (SMG – Supramarginal gyrus)	Supramarginal gyrus	Left inferior parietal	Explicit phonological processing; phoneme analysis; decoding of new (unfamiliar) words. Especially active in beginning readers.
🧠  FRONTAL LOBE
Area (BA)	Functional name	Lobe / Location	Function relevant to reading and writing
BA 4 (M1 – Primary motor cortex)	Primary motor cortex (M1)	Frontal; precentral gyrus	Fine motor execution: precise control of the hand and fingers for handwriting. Contains the motor homunculus.
BA 6 (PM/SMA – Premotor / GMFA)	Premotor area + GMFA (Exner’s area)	Superior frontal; anterior to BA 4	Frontal Graphomotor Area (GMFA): planning and sequencing of graphomotor movements. Orthography–movement interface; crucial for fluent, automated writing.
BA 8 (FEF – Frontal eye fields)	Frontal eye fields (FEF)	Superior middle frontal	Voluntary control of saccadic eye movements during reading; visual tracking of text from left to right.
BA 44 (Broca operc. – Pars opercularis)	Pars opercularis (Broca’s)	Left inferior frontal	Phonological processing; grapheme-to-phoneme conversion; subvocal articulation during silent reading. Part of the dorsal reading circuit.
BA 45 (Broca triang. – Pars triangularis)	Pars triangularis (Broca’s)	Left inferior frontal	Syntactic processing; semantic lexical selection; planning of written discourse. Key for sentence composition and comprehension.
BA 46 (DLPFC – Dorsolateral prefrontal cortex)	Dorsolateral prefrontal cortex (DLPFC)	Middle lateral frontal	Verbal working memory; sustained attention; monitoring and self-correction during reading and writing.
BA 47 (OFC/IFG – Inferior prefrontal cortex)	Inferior prefrontal cortex (OFC/IFG)	Orbital/inferior frontal	Semantic retrieval; word selection among competitors; inhibition of incorrect responses.
BA 9 (Superior DLPFC – Superior dorsolateral prefrontal)	Superior dorsolateral prefrontal cortex	Superior lateral frontal	High-level executive control; text planning; resolving semantic ambiguities; reading metacognition.
🌿  SUBCORTICAL STRUCTURES AND CEREBELLUM
Structure	Location	Function relevant to reading and writing
Cerebellum (Lobules VI, VII, Crus I/II)	Posterior fossa	Fine motor coordination for writing; automation of graphomotor sequences; temporal processing of language; contributes to verbal and reading fluency.
Basal ganglia (Caudate nucleus, Putamen)	Deep within the cerebral hemispheres	Motor initiation; automation of graphomotor skills; selection and sequencing of learned motor routines.
Thalamus (Pulvinar nuclei, LGN)	Central diencephalon	Relay of visual information to cortex; attentional modulation; multimodal sensory integration for reading.
Corpus callosum	Interhemispheric midline	Transfer of information between hemispheres; bilateral coordination in complex literacy tasks.
🟫  BRAINSTEM
Structure	Location	Function relevant to reading and writing
Superior colliculus	Dorsal midbrain	Reflexive control of saccadic eye movements; automatic visual orienting toward text.
Locus coeruleus (LC)	Pons	Primary source of cortical norepinephrine; regulates arousal and sustained attention needed for reading.
Raphe nuclei (5-HT)	Brainstem (midbrain–pons)	Serotonergic modulation of mood and motivation; influences readiness for learning to read.
Ascending reticular activating system (ARAS)	Brainstem (distributed)	Regulates wakefulness and overall alertness; a necessary condition for any reading or writing processing.

Prepared based on:

Adams, M. J. (1990). Beginning to read: Thinking and learning about print. MIT Press.

Cohen, L., Dehaene, S., Naccache, L., Lehéricy, S., Dehaene-Lambertz, G., Hénaff, M.-A., & Michel, F. (2000). The visual word form area: Spatial and temporal characterization of an initial stage of reading in normal subjects and posterior split-brain patients. Brain, 123(2), 291–307. https://doi.org/10.1093/brain/123.2.291

Dehaene, S. (2009). Reading in the brain: The new science of how we read. Viking/Penguin.

Diamond, A. (2013). Executive functions. Annual Review of Psychology, 64, 135–168. https://doi.org/10.1146/annurev-psych-113011-143750

Luria, A. R. (1966). Higher cortical functions in man (B. Haigh, Trad.). Basic Books. (Trabajo original publicado en ruso, 1962)

Wolf, M., & Bowers, P. G. (1999). The double-deficit hypothesis for the developmental dyslexias. Journal of Educational Psychology, 91(3), 415–438. https://doi.org/10.1037/0022-0663.91.3.415

All images and schematics on this blog are protected by copyright law. Please contact the author for permission to use any materials.