Memory and trauma
Encyclopedia
Memory
is described by psychology
as the ability of an organism to store, retain, and subsequently retrieve information. When an individual experiences a traumatic event, whether physically or psychologically traumatic, his or her memory can be affected in many ways. For example, trauma might affect his or her memory for that event, memory of previous or subsequent events, or thoughts in general.
in a car accident, this can have effects on their memory. The most common form of memory disturbance in cases of severe injuries or perceived physical distress due to a traumatic event is post-traumatic stress disorder
, discussed in depth later in the article.
s, on the sides of the brain
, contain the hippocampus
and amygdala
, and therefore have a lot to do with memory transition and formation. Patients who have had injury to this area have experienced problems creating new long-term memories. For example, the most studied individual in the history of brain research, HM
, retained his previously stored long-term memory
as well as functional short-term memory
, but was unable to remember anything after it was out of his short-term memory. A patient whose fornix was damaged bilaterally suffered severe anterograde amnesia
but no effect on any other forms of memory or cognition. In the fictional case of a patient with a cherry-sized tumor pressing on the temporal lobe of his brain, he temporarily suffered total retrograde amnesia
, even after surgery was performed to remove the tumor. However, with time, he was not only able to remember everything starting after the surgery, but childhood memories, up to age 12, all returned with clarity.
and hypothalamus
, peripheral cortex and temporal cortex. The hippocampus and amygdala have been connected with transference of memory from short-term memory to long-term memory. Thalamus and hypothalamus, located in the forebrain, are part of the limbic system
; they are responsible for regulating different hormones and emotional and physical reactions to situations, including emotional stress
or trauma. The thalamus is also related to reception of information and transferring the information, in the case of memories, to the cerebral cortex
.
has great effects on physical aspects of patients’ brains, to the point that it can have detrimental effects akin to actual physical brain damage
. The hippocampus, as mentioned above, is involved in the transference of short-term memories to long-term memories and it is especially sensitive to stress. Stress causes glucocorticoid
s (GCs), adrenal hormones, to be secreted and sustained exposure to these hormones can cause neural degeneration. The hippocampus is a principal target site for GCs and therefore experiences a severity of neuronal damage that other areas of the brain do not. In severe trauma patients, especially those with post-traumatic stress disorder, the medial prefrontal cortex
is volumetrically smaller in size than normal and is hyporesponsive when performing cognitive tasks, which could be a cause of involuntary recollection (intrusive thoughts). The medial prefrontal cortex controls emotional responsiveness and conditioned fear responses to fear-inducing stimuli by interacting with the amygdala. In those cases, the metabolism
in some parts of the medial prefrontal cortex didn’t activate as they were supposed to when compared to those of a healthy subject.
originated the concept of repression and it has developed and changed since his original work. In the eyes of critics of repressed memory, it is synonymous with false memory; however its proponents will argue that these people truly did have traumatic experiences.
or obsessive-compulsive disorder
, the thoughts are not as easy to ignore and can become troubling and severe. These thoughts are not typically acted on; the obsession of the thoughts usually comes from intense guilt, shame or anxiety relating to the fact that the patient is having the thoughts to begin with so they are unlikely to actually act on things they feel so badly about. In trauma patients, the intrusive thoughts are typically memories from traumatic experiences that come at unexpected and unwanted times. The primary difference from other intrusive thoughts sufferers is that the memories are real rather than imagined.
, are interrelated with strong negative emotions, causing these memories to be very strong and more easily recalled than memories not associated with similar emotions, or even those connected to positive emotions. Emotion's strong connection with memory also has to do with how much attention or focus an individual has on the event. If they are heavily emotionally involved in the event, a lot of their attention is directed at what’s happening, rendering it a stronger memory. It is also the case with emotionally aroused situations that even if attention is limited, it is more likely that a memory associated with the strong emotion will remain as opposed to some neutral stimulus
. Chemically, this is because the emotional and physical stress caused by traumatic events creates an almost identical stimulation in the brain to the physiological condition that heightens memory retention. It excites the neuron-chemical activity centers of the brain that affects memory encoding and recollection. This reaction has been enforced by evolution as learning from high-stress environments is necessary in "fight or flight
" decisions that characterize human survival.
, therapy is needed to help recover memories. Drug therapy
is more common in cases where the psychological trauma caused chemical imbalances and other physical changes in the brain which affected memory. Patients who use drug therapy also frequent some type of psychotherapy
as well.
Memory
In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
is described by psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
as the ability of an organism to store, retain, and subsequently retrieve information. When an individual experiences a traumatic event, whether physically or psychologically traumatic, his or her memory can be affected in many ways. For example, trauma might affect his or her memory for that event, memory of previous or subsequent events, or thoughts in general.
Physical trauma
When people experience physical trauma, such as a head injuryHead injury
Head injury refers to trauma of the head. This may or may not include injury to the brain. However, the terms traumatic brain injury and head injury are often used interchangeably in medical literature....
in a car accident, this can have effects on their memory. The most common form of memory disturbance in cases of severe injuries or perceived physical distress due to a traumatic event is post-traumatic stress disorder
Post-traumatic stress disorder
Posttraumaticstress disorder is a severe anxiety disorder that can develop after exposure to any event that results in psychological trauma. This event may involve the threat of death to oneself or to someone else, or to one's own or someone else's physical, sexual, or psychological integrity,...
, discussed in depth later in the article.
Brain damage
Damage to different areas of the brain can have varied effects on memory. The temporal lobeTemporal lobe
The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
s, on the sides of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
, contain the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
and amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
, and therefore have a lot to do with memory transition and formation. Patients who have had injury to this area have experienced problems creating new long-term memories. For example, the most studied individual in the history of brain research, HM
HM (patient)
Henry Gustav Molaison , famously known as HM or H.M., was an American memory disorder patient who was widely studied from late 1957 until his death...
, retained his previously stored long-term memory
Long-term memory
Long-term memory is memory in which associations among items are stored, as part of the theory of a dual-store memory model. According to the theory, long term memory differs structurally and functionally from working memory or short-term memory, which ostensibly stores items for only around 20–30...
as well as functional short-term memory
Short-term memory
Short-term memory is the capacity for holding a small amount of information in mind in an active, readily available state for a short period of time. The duration of short-term memory is believed to be in the order of seconds. A commonly cited capacity is 7 ± 2 elements...
, but was unable to remember anything after it was out of his short-term memory. A patient whose fornix was damaged bilaterally suffered severe anterograde amnesia
Anterograde amnesia
Anterograde amnesia is a loss of the ability to create new memories after the event that caused the amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact. This is in contrast to retrograde amnesia, where memories...
but no effect on any other forms of memory or cognition. In the fictional case of a patient with a cherry-sized tumor pressing on the temporal lobe of his brain, he temporarily suffered total retrograde amnesia
Retrograde amnesia
Retrograde amnesia is a loss of access to events that occurred, or information that was learned, before an injury or the onset of a disease....
, even after surgery was performed to remove the tumor. However, with time, he was not only able to remember everything starting after the surgery, but childhood memories, up to age 12, all returned with clarity.
Relevant memory
Of the different aspects of memory – working, short-term, long-term, etc – the one most commonly affected by psychological trauma is long-term memory. Missing memories, changes to memory, intensified memories – all are cases of manipulations of long-term memory.Physical aspect
Long-term memory is associated with many different areas of the brain including the hippocampus, amygdala, thalamusThalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
and hypothalamus
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
, peripheral cortex and temporal cortex. The hippocampus and amygdala have been connected with transference of memory from short-term memory to long-term memory. Thalamus and hypothalamus, located in the forebrain, are part of the limbic system
Limbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...
; they are responsible for regulating different hormones and emotional and physical reactions to situations, including emotional stress
Stress (medicine)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
or trauma. The thalamus is also related to reception of information and transferring the information, in the case of memories, to the cerebral cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
.
Physical effects
Psychological traumaPsychological trauma
Psychological trauma is a type of damage to the psyche that occurs as a result of a traumatic event...
has great effects on physical aspects of patients’ brains, to the point that it can have detrimental effects akin to actual physical brain damage
Brain damage
"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...
. The hippocampus, as mentioned above, is involved in the transference of short-term memories to long-term memories and it is especially sensitive to stress. Stress causes glucocorticoid
Glucocorticoid
Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...
s (GCs), adrenal hormones, to be secreted and sustained exposure to these hormones can cause neural degeneration. The hippocampus is a principal target site for GCs and therefore experiences a severity of neuronal damage that other areas of the brain do not. In severe trauma patients, especially those with post-traumatic stress disorder, the medial prefrontal cortex
Prefrontal cortex
The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
is volumetrically smaller in size than normal and is hyporesponsive when performing cognitive tasks, which could be a cause of involuntary recollection (intrusive thoughts). The medial prefrontal cortex controls emotional responsiveness and conditioned fear responses to fear-inducing stimuli by interacting with the amygdala. In those cases, the metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
in some parts of the medial prefrontal cortex didn’t activate as they were supposed to when compared to those of a healthy subject.
Psychological effects
As with many areas of psychology, most of these effects are under constant review, trial, and dissent within the scientific world regarding the validity of each topic.Repressed memory
Perhaps one of the most controversial and well-known of the psychological effects trauma can have on patients is repressed memory. The theory/reality of repressed memory is the idea that an event is so traumatic, that the memory was not forgotten in the traditional sense, or kept secret in shame or fear, but removed from the conscious mind, still present in the long-term memory but hidden from the patient's knowledge. Sigmund FreudSigmund Freud
Sigmund Freud , born Sigismund Schlomo Freud , was an Austrian neurologist who founded the discipline of psychoanalysis...
originated the concept of repression and it has developed and changed since his original work. In the eyes of critics of repressed memory, it is synonymous with false memory; however its proponents will argue that these people truly did have traumatic experiences.
Intrusive thoughts
Intrusive thoughts are defined as unwelcome, involuntary thoughts, images or unpleasant ideas that may become obsessions, are upsetting or distressing, and can be difficult to be free of and manage. In patients who have suffered from traumatic events, especially those with post-traumatic stress disorder, depressionClinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
or obsessive-compulsive disorder
Obsessive-compulsive disorder
Obsessive–compulsive disorder is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing the associated anxiety, or by a combination of such obsessions and compulsions...
, the thoughts are not as easy to ignore and can become troubling and severe. These thoughts are not typically acted on; the obsession of the thoughts usually comes from intense guilt, shame or anxiety relating to the fact that the patient is having the thoughts to begin with so they are unlikely to actually act on things they feel so badly about. In trauma patients, the intrusive thoughts are typically memories from traumatic experiences that come at unexpected and unwanted times. The primary difference from other intrusive thoughts sufferers is that the memories are real rather than imagined.
Emotion
Emotion is a large part of trauma, especially near death experiences. The effect emotions have on memory in different instances is an integral part of the effect of trauma on memory. Emotional events tend to be recalled with more frequency and clarity than memories not associated with extreme emotions. Typically traumatic events, such as physical attack or sexual abuseSexual abuse
Sexual abuse, also referred to as molestation, is the forcing of undesired sexual behavior by one person upon another. When that force is immediate, of short duration, or infrequent, it is called sexual assault. The offender is referred to as a sexual abuser or molester...
, are interrelated with strong negative emotions, causing these memories to be very strong and more easily recalled than memories not associated with similar emotions, or even those connected to positive emotions. Emotion's strong connection with memory also has to do with how much attention or focus an individual has on the event. If they are heavily emotionally involved in the event, a lot of their attention is directed at what’s happening, rendering it a stronger memory. It is also the case with emotionally aroused situations that even if attention is limited, it is more likely that a memory associated with the strong emotion will remain as opposed to some neutral stimulus
Neutral stimulus
A neutral stimulus is a stimulus which initially produces no specific response other than focusing attention. In classical conditioning, when used together with an unconditioned stimulus, the neutral stimulus becomes a conditioned stimulus....
. Chemically, this is because the emotional and physical stress caused by traumatic events creates an almost identical stimulation in the brain to the physiological condition that heightens memory retention. It excites the neuron-chemical activity centers of the brain that affects memory encoding and recollection. This reaction has been enforced by evolution as learning from high-stress environments is necessary in "fight or flight
Fight-or-flight response
The fight-or-flight response was first described by Walter Bradford Cannon....
" decisions that characterize human survival.
Post-traumatic stress disorder
PTSD is an anxiety disorder caused by exposure to a terrifying event or ordeal involving the occurrence or threat of physical harm. It is one of the most severe and well-known of the different types of psychological trauma, mostly due to it’s prevalence in war veterans. As mentioned above, the stress of PTSD can have severe effects on the hippocampus, causing problems with transferring short-term to long-term memory. There is no one way that patients’ memories are affected by PTSD, as shown by a variety of studies. Typically symptoms include avoidance of reminders of the traumatic event or mention thereof, irritability, trouble sleeping, emotional numbness and exaggerated reactions to surprises. One of the most common and powerful symptoms, is the recurrence of random intense memories from the event (intrusive thoughts). This can manifest itself in different ways such as flashbacks of the event and unwanted thoughts about the trauma (e.g. “why did this happen to me?”). PTSD patients who have gone through different traumatic experiences will have small variances in their symptoms, mostly insignificant. For example, PTSD patients who were rape victims will have aversion to words such as touch and dirty while patients who were in a fire or war experience will respond similarly to words like burn or fight.Therapy
For patients who have suffered physical trauma that led to their memory damage, surgery can sometimes get them back to normal. Sometimes, as in the case of the patient mentioned above who had a tumor that caused his memory lossMemory loss
Memory loss can be partial or total and it is normal when it comes with aging. Sudden memory loss is usually a result of brain trauma and it may be permanent or temporary. When it is caused by medical conditions such as Alzheimers, the memory loss is gradual and tends to be permanent.Brain trauma...
, therapy is needed to help recover memories. Drug therapy
Pharmacology
Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...
is more common in cases where the psychological trauma caused chemical imbalances and other physical changes in the brain which affected memory. Patients who use drug therapy also frequent some type of psychotherapy
Psychotherapy
Psychotherapy is a general term referring to any form of therapeutic interaction or treatment contracted between a trained professional and a client or patient; family, couple or group...
as well.