Ventral parietal cortex contributions to episodic memory precision

Functional imaging studies examining the neural mechanisms enabling memory precision for episodic information relate that function to enhanced activation in the ventral parietal cortex (VPC). However, the VPC role in mnemonic precision remains ambiguous due to the correlative, rather than causative, nature of evidence provided by functional neuroimaging. We therefore aimed to neuroanatomically assess the VPC involvement in episodic memory retrieval requiring precision regarding stimulus details vs. its contribution to more general remembering.

Stroke patients with right hemisphere or left hemisphere damage, primarily within the middle cerebral artery territory, and healthy controls performed two recognition memory tasks matched for difficulty: (a) a detail-focused object recognition memory task where probe foils differed from studied stimuli only in subtle visual details, and (b) a gist-based object recognition memory task with target probes that differed from studied stimuli visually but not conceptually, alongside unrelated foils. Voxel-based lesion-symptom mapping (VLSM) analyses were employed to identify brain regions critical for precision versus gist memory.

Lesion analysis showed that lateral fronto-parietal damage was associated with reduced performance on the detail-focused task, whereas performance on the gist-based task did not show comparable lesion-performance associations.

These findings suggest that VPC supports memory precision needed for retrieval of fine-grained details, but is not essential for gist-based retrieval of episodic information.