Memory is fundamental to our daily functioning and sense of self, yet it can be fallible and fragile. Memory disorders represent a diverse group of conditions that disrupt our ability to encode, store, or retrieve information. Memory disorders can range from mild forgetfulness to severe impairments that profoundly affect an individual’s quality of life.

Memory impairments are prevalent across many clinical conditions, including amnesia, traumatic brain injury, and neurodegenerative conditions such as Alzheimer’s disease. Cases of amnesia, such as Patient HM after surgical removal of his hippocampi, are among the earliest documentations of brain-related memory dysfunction. Traumatic brain injuries and concussions have also been shown to be related to memory impairment, particularly short-term memory loss (McDowell et al., 1997; Malojcic et al., 2008; Covassin & Elbin, 2010). Neurodegenerative conditions, such as Alzheimer’s disease, can also be characterized by short-term and long-term memory degradation (covered in more detail in Chapter 11). Researchers have been working intensely to understand how disruptions to neural, genetic, and vascular systems may give rise to different types of memory dysfunction (Morely & Farr, 2014; El Haj et al., 2016; Religa et al., 2013). As our population ages and the prevalence of memory disorders such as dementia and Alzheimer’s increases, understanding these disorders will be increasingly relevant to society.

Another memory-related condition that may affect younger adults and is interesting to students is Korsakoff’s syndrome. This section concludes with an examination of Korsakoff’s syndrome, exploring its effects and neurobiological underpinnings.

Korsakoff’s Syndrome

Korsakoff’s syndrome is a disorder resulting from a severe deficiency of thiamine. Thiamine (vitamin B-1) is essential for metabolic processes, such as producing energy from glucose. Dietary thiamine is found in whole grains, legumes such as beans and peas, and some meats and fish. Healthy people with a well-balanced diet get sufficient thiamine, however, gastrointestinal illnesses can cause an inability to absorb thiamine properly. The body’s ability to absorb thiamine is also disrupted by chronic alcohol misuse. Alcohol misuse, in addition to its toxic effects on brain cells, can cause Korsakoff’s syndrome. While chronic alcohol consumption is the primary cause of Korsakoff’s syndrome, malnutrition, eating disorders, and genetic factors can also increase susceptibility to the condition.

People with Korsakoff’s syndrome experience several kinds of cognitive and memory impairments. They can have both retrograde and anterograde amnesia, as well as severely impaired short-term memory. The patients may confabulate or make up information they can’t remember. People who confabulate do not consciously recognize that their statements are untrue, and are not intentionally trying to deceive others, which is why it is sometimes called “honest lying.” Generally, confabulation only happens as a person is trying to recall recent autobiographical memories; their semantic and procedural memories are less susceptible to confabulation. Scientists propose that individuals with retrograde amnesia confabulate to fill memory gaps.

Korsakoff’s syndrome leads to decreased glucose metabolism in the brain, reducing its primary fuel source, and causes destruction of both neurons and glial cells. As a result of this cell loss, there is often shrinkage of the cortex, thalamus, cerebellum, and hippocampus. Korsakoff’s syndrome can be treated by giving thiamine supplements and eliminating alcohol consumption. If treated within days after the onset of brain damage, people generally recover completely. However, one of the major challenges is making a proper diagnosis, since the symptoms of Korsakoff’s syndrome present similarly to other disorders.

Text Attributions

Parts of this section were adapted from:

Hedges, V. (2022). Memory Systems. In Introduction to Neuroscience. CC BY-NC-SA 4.0 https://openbooks.lib.msu.edu/introneuroscience1/chapter/memory-systems/

Lim, A., & Graykowski, D. (2021). Learning and Memory. In Open Neuroscience Initiative. CC BY-NC 4.0 https://static1.squarespace.com/static/56555dbee4b0f0c1a002808a/t/60537c185d98a2151537dbba/1616084000764/Open+Neuroscience+Initiative+-+Chapter+13+-+Learning+and+Memory.pdf