Stress-related memory loss: causes and symptoms

This cognitive problem may be a sign of having gone through a period of high mental stress.

Whether transient or sustained, the physiological stress response alters memory, causing difficulties in retaining new information and retrieving established memories.

However, the effects of stress on memory can the effects of stress on memory can be somewhat contradictory, however, and differ and differ depending on whether we are talking about acute or chronic stress.

Relationship between stress and memory loss

When the demands of the situation in which we find ourselves exceed our physical and/or cognitive capacities, our body activates the stress response. This consists of the release of glucocorticoids, the stress hormones, into the bloodstream.

Glucocorticoids have various effects on the body, including increased heart rate and respiratory rate, reduced gastrointestinal activity and the release of stored glucose reserves for use as a source of energy.

If their concentration is excessive, glucocorticoids, of which cortisol is the most important, can have a negative effect on the functions of the hippocampus, a brain structure associated with the formation and retrieval of memories. This is partly because glucocorticoids redirect glucose from the hippocampus to nearby muscles.

Two types of stress have been described according to their origin: extrinsic and intrinsic stress.. Extrinsic stress is caused by non-cognitive factors, such as those arising from a given situation, while intrinsic stress is related to the level of intellectual challenge required by a task. Some people have chronic intrinsic stress.

Stress interferes both with our ability to retain new information and to retrieve memories and knowledge, causing memory loss. In addition, extrinsic stress appears to affect spatial learning. We will describe these effects in more detail in the following sections.

Yerkes-Dodson's Law: the inverted U

The Yerkes-Dodson law states that stress does not always interfere negatively with cognition, but that a moderate degree of stress does not always interfere negatively with spatial learning.Rather, a moderate degree of brain activation improves memory and performance in intellectual tasks. Conversely, excessive increases in stress levels worsen cognitive functions.

This gives rise to the so-called "inverted U effect": if our organism responds to environmental demands with mild or moderate stress responses, the efficiency of our productivity increases until it reaches a threshold (the ideal activation point) after which performance progressively declines and memory loss occurs.

Overly intense stress responses interfere with the performance of intellectual tasks because they are associated with physical and cognitive symptoms such as concentration difficulties, tachycardia, sweating, dizziness or hyperventilation.

Effects of acute or transient stress

When we are in a stressful situation our attention is focused on the most salient stimuli, while we pay less attention to the rest; this phenomenon is known as "tunnel vision" and facilitates the consolidation of some memories while interfering with the consolidation of others, causing memory loss.

Acute stress may have beneficial effects on some types of memory but only under certain conditions. In this regard, it is worth mentioning again the Yerkes-Dodson law; on the other hand, some studies have shown that glucocorticoids improve the formation of new memories but worsen the retrieval of other memories. but worsen the retrieval of existing memories.

In addition, emotionally relevant stimuli are better remembered if the stress response has occurred previously, if information retrieval takes place shortly after encoding, and if the recall situation is similar to the learning situation.

Other research suggests that, under stressful conditions, we learn and recall to a greater extent information and situations that cause us emotional discomfort. This is associated with the mood congruency effect described by Gordon H. Bower, who describes similar results in relation to depression.

Consequences of chronic stress

The stress response not only leads to changes in memory at the time it occurs, but if it is chronically sustained, it can cause long-term damage to the brain. Since the organism consumes many resources and reserves in the activation of these physiological processes, chronic stress is significantly more damaging than acute stress..

After acute or transitory stress situations, our body recovers homeostasis, i.e. physiological equilibrium, whereas chronic stress prevents the organism from reaching homeostasis again. Therefore, if stress is maintained, it unbalances the body's responses.

From a physiological point of view, this facilitates the appearance of symptoms such as abdominal, back and headaches, chronic difficulties in concentrating and falling or staying asleep, anxiety crises, etc. In addition, continued stress is associated with social isolation, depression and the development of Cardiovascular diseases.

As for memory loss, chronic stress increases the risk of dementia in the elderly. These effects are probably related to glucocorticoid activity in the hippocampus and other brain regions on which memory and cognition in general depend.