Related Experiment Video
Updated: May 18, 2026
09:43
Reversible Cooling-induced Deactivations to Study Cortical Contributions to Obstacle Memory in the Walking Cat
Published on: December 11, 2017
Explaining the encoding/retrieval flip: memory-related deactivations and activations in the posteromedial cortex.
W Huijbers1, P Vannini, R A Sperling
1Harvard Medical School, Martinos Center for Biomedical Imaging, Brigham and Women's Hospital, Boston, MA, USA. huijbers@nmr.mgh.harvard.edu
Neuropsychologia
|September 18, 2012
Summary
The posteromedial cortex (PMC) shows an encoding/retrieval flip (E/R-flip) pattern, crucial for episodic memory. This review explores PMC function, its E/R-flip, and links to Alzheimer's disease and aging.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neuroimaging
Background:
- The posteromedial cortex (PMC) is implicated in episodic memory and age-related memory decline.
- PMC exhibits deactivations during cognitive tasks, linked to the default-mode network.
- A unique encoding/retrieval flip (E/R-flip) in PMC activity during memory tasks remains poorly understood.
Purpose of the Study:
- To review the neurofunctional and clinical significance of the PMC's E/R-flip pattern.
- To examine hypotheses explaining PMC function in memory.
- To discuss the role of PMC in aging and Alzheimer's disease (AD).
Main Methods:
- Review of existing literature on PMC function, E/R-flip, and neuroimaging studies.
- Analysis of hypotheses including internal orienting, self-referential processing, reallocation, and bottom-up attention.
- Examination of clinical data related to aging, AD, and amyloid deposition in PMC.
Main Results:
- No single neurofunctional hypothesis fully explains the PMC E/R-flip.
- Amyloid deposits in PMC precede clinical memory deficits in AD, impairing memory encoding.
- The PMC comprises distinct functional subdivisions: precuneus, retrosplenial cortex, and posterior cingulate cortex.
Conclusions:
- The PMC's E/R-flip pattern is complex and not fully explained by current neurofunctional models.
- Amyloid burden in PMC significantly impacts memory encoding, particularly attenuating beneficial deactivations.
- Understanding PMC subdivisions is key to interpreting its varied functional signals in memory and disease.
Related Concept Videos
01:23Somatosensory, Motor, and Association Cortex
The somatosensory cortex in the parietal lobes is crucial for interpreting sensory data such as touch, temperature, and proprioception. The somatosensory cortex, situated in the parietal lobes, plays a vital role in interpreting sensory information like touch, temperature, and proprioception—awareness of body position. This specialized brain region features an organized structure wherein neurons at the top primarily process sensations originating from the lower body. In contrast, those at the...
01:14Role of Cerebellum and Prefrontal Cortex in Memory
The cerebellum, while traditionally associated with motor control, also plays a crucial role in memory, particularly in procedural memory, which involves learning motor tasks that become automatic through repetition. For example, studies have shown that when the cerebellum is damaged, individuals or animals lose the ability to learn conditioned motor responses, such as the conditioned eye-blink response in classical conditioning experiments with rabbits. This study demonstrates the cerebellum's...
01:14Motor and Sensory Areas of the Cortex
The cerebral cortex, the brain's outermost layer, is pivotal in processing complex cognitive tasks, emotions, and various sensory inputs and executing voluntary motor activities. This intricate structure is divided into three primary functional areas: the motor areas, sensory areas, and association areas.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
Motor Areas
The motor areas located in the frontal lobe are central to controlling voluntary movements. This region is further subdivided into the primary motor cortex and the premotor cortex.
01:19Role of Hippocampus in Memory
The hippocampus, a critical brain structure, plays an essential role in memory processing, particularly in the formation and retrieval of memory. This small, seahorse-shaped region is located within the medial temporal lobe, with one hippocampus in each brain hemisphere. Experimental studies involving lesions in the hippocampi of rats have demonstrated significant impairments in tasks such as object recognition and maze navigation, indicating the hippocampus involvement in both recognition and...
01:33Somatosensation
The somatosensory system relays sensory information from the skin, mucous membranes, limbs, and joints. Somatosensation is more familiarly known as the sense of touch. A typical somatosensory pathway includes three types of long neurons: primary, secondary, and tertiary. Primary neurons have cell bodies located near the spinal cord in groups of neurons called dorsal root ganglia. The sensory neurons of ganglia innervate designated areas of skin called dermatomes.