3.5.13 Memory

Memory Including in Dementia and Post-Traumatic Stress Disorder

Memory is the cognitive process by which the brain encodes, stores, and retrieves information. It is mediated by a network of neural circuits that involve the integration of information from multiple brain regions.

The hippocampus, a key brain region involved in the formation of new memories and the consolidation of short-term memories into long-term memories, plays a central role in memory.

Other brain regions involved in memory include the prefrontal cortex, which is responsible for higher-level cognitive functions such as decision-making and problem-solving and is involved in memory retrieval, and the amygdala, which is involved in the processing of emotions and the formation of emotional memories.

Dysfunctions in these neural circuits may be associated with conditions such as Alzheimer’s disease and other forms of dementia. Understanding the neural circuits involved in memory is important for understanding how the brain encodes, stores, and retrieves memories and for developing treatments for memory impairments.

Dementia:

Dementia is a term used to describe a decline in cognitive function, including memory, language, and problem-solving abilities, that is severe enough to interfere with daily life. It is often associated with neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and frontotemporal dementia.

Dementia is thought to be mediated by the degeneration and death of brain cells in certain brain regions, as well as the formation of abnormal protein deposits in the brain. This can lead to dysfunction in the neural circuits involved in cognitive functions such as memory, language, and problem-solving.

Dementia:	Protein deposition
Alzheimer’s disease	In Alzheimer’s disease, abnormal protein deposits known as amyloid plaques and tau tangles form in the brain. Amyloid plaques are composed of a protein called beta-amyloid that accumulates outside of brain cells, while tau tangles are composed of a protein called tau that accumulates inside of brain cells. These protein deposits are thought to contribute to the death of brain cells and the decline in cognitive function seen in Alzheimer’s disease.
Parkinson’s disease	In Parkinson’s disease, abnormal protein deposits known as Lewy bodies form in the brain. Lewy bodies are composed of a protein called alpha-synuclein and are thought to contribute to the death of brain cells and the decline in cognitive function seen in Parkinson’s disease.

(Frost, 2010).

One key brain region involved in memory that is often affected in dementia is the hippocampus, which is responsible for the formation of new memories and the consolidation of short-term memories into long-term memories. Other brain regions that may be affected in dementia include the prefrontal cortex, which is responsible for higher-level cognitive functions such as decision-making and problem-solving, and the amygdala, which is involved in the processing of emotions.

Post-Traumatic Stress Disorder:

Post-traumatic stress disorder (PTSD) is a mental disorder that can develop after exposure to a traumatic event, such as a natural disaster, a car accident, or a sexual assault. It is characterized by symptoms such as re-experiencing the traumatic event, avoidance of reminders of the event, and negative changes in mood and cognition.

PTSD is thought to be mediated by dysfunction in the neural circuits involved in the processing of emotions, particularly fear. One key brain region involved in the processing of fear is the amygdala, which is responsible for the processing of emotions and the formation of emotional memories. The amygdala receives inputs from the primary sensory cortices and is involved in the detection and interpretation of threats.

Other brain regions involved in the processing of emotions and the development of PTSD include the prefrontal cortex, which is responsible for higher-level cognitive functions such as decision-making and problem-solving and is involved in the regulation of emotions, and the hippocampus, which is involved in the consolidation of memories and the regulation of stress. Dysfunctions in these brain regions and their interactions with other neural circuits may contribute to the development and maintenance of PTSD.

References:

(1) Frost, B., & Iqbal, K. (2010). Tau and amyloid in Alzheimer’s disease. Journal of Molecular Neuroscience, 41(2), 141-149.

(2) Shin, L. M., Rauch, S. L., & Pitman, R. K. (2006). The functional neuroanatomy of PTSD: A critical review. Progress in Brain Research, 167, 181-197.