Precuneus (Left)

Overview

The left precuneus is a medial parietal lobe structure located on the posteromedial surface of the cerebral hemisphere, bounded anteriorly by the marginal branch of the cingulate sulcus and posteriorly by the parieto-occipital sulcus. Cytoarchitectonically, it is part of the superior parietal lobule and participates in widespread functional networks, including the default mode network. Functionally, the left precuneus is implicated in visuospatial imagery, self-referential processing, episodic memory retrieval, and aspects of consciousness and awareness, integrating multimodal sensory and mnemonic information. It maintains dense reciprocal connections with the posterior cingulate cortex, medial prefrontal regions, lateral parietal cortex, and thalamic nuclei, supporting its role as a hub for internally directed cognition and large-scale brain network coordination. Precuneus

The left precuneus, as defined in the AAL2 atlas, has been implicated in multiple imaging-genetics and GWAS-based endophenotype studies, which link common variants to both its structure and function. Large-scale MRI GWAS (e.g., ENIGMA, UK Biobank) have identified associations between precuneus volume or cortical thickness and variants in genes involved in neurodevelopment, synaptic function, and myelination, including loci near genes such as HMGA2, MAPT, and microtubule- or axon-guidance–related genes, though effects are typically small and regionally overlapping rather than specific to the left precuneus alone. Polygenic risk scores for Alzheimer’s disease, schizophrenia, major depression, and autism spectrum disorder show correlations with structural or functional alterations in the precuneus, consistent with this region’s role in default mode network connectivity and self-referential processing. Functional imaging–genetics work has linked APOE ε4 and other Alzheimer’s risk variants to hypometabolism or altered connectivity in the precuneus, while schizophrenia and depression risk loci (e.g., in CACNA1C and ZNF804A) have been associated with default mode network changes that prominently involve the precuneus. GWAS of cognitive traits (intelligence, memory, educational attainment) and personality or behavioral traits (e.g., neuroticism) also report that polygenic scores relate to precuneus morphology or activation patterns, although the associations are typically part of broader, distributed cortical effects rather than being uniquely localized to the left precuneus.

Overview generated by GPT-4o (2026).

Region ID: 6301
Hemisphere: left
Atlas: AAL2

Precuneus (Left) – Black Background (Full Brain)

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Precuneus (Left) – White Background (Full Brain)

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Precuneus (Left) – Black Background (Hemisphere)

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Precuneus (Left) – White Background (Hemisphere)

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Triplanar View – T1 Background

Triplanar View – Ghost Brain