How does the human brain store and retrieve memories?

Introduction

The human brain's ability to store and retrieve memories is a complex process involving various neural mechanisms and brain regions. Understanding these processes is crucial for insights into cognitive functions and potential treatments for memory-related disorders.

Key Insights

Short-term Memory Storage:
- Short-term memories are stored by patterns of neuronal activity within neural networks exhibiting nested oscillations. Each memory is stored in a different high-frequency subcycle of a low-frequency oscillation.
Role of the Prefrontal Cortex in Long-term Memory Retrieval:
- Long-term memory retrieval is regulated by top-down processes originating from the prefrontal cortex. The anterior corpus callosum plays a role in instructing hemispheres to retrieve the correct stimulus based on visual cues.
Neocortex and Memory Consolidation:
- Initial storage of facts and events involves the hippocampus, but permanent storage occurs in specific neocortical regions. The prefrontal and temporal cortices show increased activity during remote memory retrieval, and damage to these areas results in selective memory deficits.
Fluid Nature of Memory Retrieval:
- Memory retrieval is not a fixed process; it plays a crucial role in shaping memory over time. This challenges the traditional view that the hippocampus is not involved in retrieving older episodic memories.
Synaptic vs. Intrinsic Hypotheses of Memory Storage:
- The dominant view is that memory is stored in synapses, supported by studies on sea slugs and mice. However, there is a growing minority that suggests memory might be stored at the molecular level within neurons, as evidenced by experiments on RNA and DNA transfer.
Molecular Mechanisms of Memory Retrieval:
- Memory formation and retrieval may share molecular mechanisms in the hippocampus. Retrieval involves activation of several signaling cascades and protein synthesis, indicating a complex molecular process.

Conclusion

The storage and retrieval of memories in the human brain involve intricate neural and molecular mechanisms. Short-term memories are stored through oscillatory patterns in neural networks, while long-term memories are consolidated in the neocortex and retrieved under the control of the prefrontal cortex. The process of memory retrieval is dynamic and can reshape memories over time. While the synaptic hypothesis remains dominant, there is emerging evidence supporting the cell-intrinsic hypothesis. Understanding these processes at both the neural and molecular levels is essential for advancing cognitive neuroscience.

How does the human brain store and retrieve memories?

Summary

Introduction

Key Insights

Conclusion

Sources and full results

Storage of 7 +/- 2 short-term memories in oscillatory subcycles

Brain oscillations serve as a timing mechanism for storing and processing short-term memories, with each memory stored in a different high-frequency subcycle of a low-frequency oscillation.

Callosal window between prefrontal cortices: cognitive interaction to retrieve long-term memory.

Visual long-term memory is stored in the temporal cortex, but memory retrieval is under the executive control of the prefrontal cortex.

New Circuits for Old Memories The Role of the Neocortex in Consolidation

Neocortical regions, specifically the prefrontal cortex and temporal cortex, play a crucial role in storing our oldest and most defining memories.

Mysteries of the brain. How are memories retrieved?

Memory recall is a fluid process, with the hippocampus playing a crucial role in retrieving older episodic memories and the neocortex shaping memory over time.

Where is Memory Information Stored in the Brain?

Memory information in the brain is commonly believed to be stored in the synapse, but alternatively, it may be stored inside the neuron at the molecular (RNA or DNA) level.

Molecular Mechanisms of Memory Retrieval

Memory retrieval in the hippocampus involves shared molecular mechanisms with memory formation, requiring activation of signaling cascades and protein synthesis.

STORAGE AND RETRIEVAL PROCESSES IN LONG-TERM MEMORY 1

Human memory consists of three memory stores: sensory register, short-term store, and long-term store, with retrieval efficiency decreasing as new information is added to each store.

Functional integrity of the retrosplenial cortex is essential for rapid consolidation and recall of fear memory.

The anterior part of the retrosplenial cortex plays a crucial role in rapid consolidation and recall of fear memories, challenging the idea that neocortical areas are slow encoding systems only involved in remote memory retrieval.

Holographic model on the mechanism of memory encoding, storage, and retrieval in the brain

The holographic model suggests that memory encoding in the brain occurs through hologram generation in synapses, with hippocampus emitting the same energy wave used for encoding and consciousness enabling reconstruction of the signal wave from the hologram.

Memory Retrieval in Mice and Men.

Memory retrieval in mice and humans involves coordinated fast interplay of sparse and distributed corticohippocampal and neocortical networks, driven by activity patterns during encoding but malleable to time and interaction with novel information.

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