TRAUMATIC MEMORIES: NEURONS AND LANGUAGE
Paraphrasing the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders), a “trauma” is an occasion during which the person experienced, witnessed or was confronted with an event or events that involved actual or threatened death or serious injury, or a threat to the physical integrity of self or others. This definition is very objective, but it doesn’t consider subjective variables that can be very important both during the exposure to trauma and its subsequent elaboration. Many traumatized patients who seek for clinical advice, in fact, are affected by post-traumatic conditions even in absence of true objective consequences. This observation led clinicians to hypothesize that these phenomena are not simply generated by an objective event but rather by a traumatic interpretation of it.
Traumas, like any other experience, are transduced into neural activity. One of the most known effects is the production of catecholamines (adrenaline and noradrenaline, chemical compounds produced by the adrenal glands), which trigger an increase in the activity of the sympathetic nervous system.
This system, which is usually not consciously controllable, generally activates in dangerous or, more broadly, exciting situations. Furthermore, the level of endogenous opioids, substances that usually inhibit neural transmission, greatly increases after exposure to traumatic experiences. Such high concentration can interfere with the acquisition of new memories1. The repeated exposure to certain types of distressing situations modifies the adaptation of such chemical compounds making these changes semi-permanent because of the effects they have on several brain areas involved in the encoding and storage of emotionally significant events.
Memories of traumatic experiences, in fact, are encoded in the brain in a different way than normal experiences. That’s why traumatic memories are often blurred but hard to forget. A study conducted in 2005 on animal models demonstrated that emotionally neutral events are recalled only for a short period of time and are not stored in the so-called long-term memory. On the other hand, emotionally relevant and stressful events, such as a terrifying situations, are remembered even after a single exposure because of the activation of the amygdala (an almond shaped structure which resides in the temporal lobe, involved in the processing of emotional stimuli) and of other areas that are more directly involved in mnestic functions such as the hippocampus (the main area involved in the acquisition of new memories)2.
Along with the temporal lobe, traumatic experiences have consequences on other cortical areas. For instance, a study, in which magnetic resonances of abused children and adolescents were collected, found cortical atrophy and the enlargement of brain ventricles (large ventricles usually indicate a reduction in the cerebral cortex’s volume) in these subjects. The authors of the research, observed in participants suffering from post-traumatic stress, a reduction of the prefrontal cortex, the temporal lobe and the corpus callosum3. The reduction of the volume of frontal areas may be related to interferences in the ability to plan responses to new, non-stereotyped situations, more specifically to impairments in the ability to evaluate and react to external threats.
These problems, which are linked to the elaboration of trauma and of the adverse situations that may occur after the triggering traumatic experience, lead victims of severe traumas to an inevitable difficulty in the establishment of helping relationships with mental healthcare professionals. In fact, it seems that in people suffering from Post-Traumatic Stress Disorder (PTSD), the Broca area, located in the left frontal lobe, is less active compared to that of who never experienced traumatic events4. This area, among the most studied in the field of neuroscience, is classically defined as the language area because it is involved in linguistic production. Damages to this area can lead to communication difficulties and to the development of anxious responses in situations in which the verbalization of a traumatic memory is explicitly requested.
Despite that, it seems that psychotherapy can act on the same frontal areas that are struck by traumas, strengthening them. Thanks to functional magnetic resonance, in fact, it has been possible to demonstrate that, after only 16 sessions, patients suffering from PTSD, besides a subjective feeling of improvement, showed a decreased activation of frontal areas, which were hyperactive before therapy5.
In conclusion, the establishment of a helping relationship seems to be useful in treating post-traumatic conditions and in recovering fundamental functions, both psychological and relational, for the well being of the individual.
Traumas, like any other experience, are transduced into neural activity. One of the most known effects is the production of catecholamines (adrenaline and noradrenaline, chemical compounds produced by the adrenal glands), which trigger an increase in the activity of the sympathetic nervous system.
This system, which is usually not consciously controllable, generally activates in dangerous or, more broadly, exciting situations. Furthermore, the level of endogenous opioids, substances that usually inhibit neural transmission, greatly increases after exposure to traumatic experiences. Such high concentration can interfere with the acquisition of new memories1. The repeated exposure to certain types of distressing situations modifies the adaptation of such chemical compounds making these changes semi-permanent because of the effects they have on several brain areas involved in the encoding and storage of emotionally significant events.
Memories of traumatic experiences, in fact, are encoded in the brain in a different way than normal experiences. That’s why traumatic memories are often blurred but hard to forget. A study conducted in 2005 on animal models demonstrated that emotionally neutral events are recalled only for a short period of time and are not stored in the so-called long-term memory. On the other hand, emotionally relevant and stressful events, such as a terrifying situations, are remembered even after a single exposure because of the activation of the amygdala (an almond shaped structure which resides in the temporal lobe, involved in the processing of emotional stimuli) and of other areas that are more directly involved in mnestic functions such as the hippocampus (the main area involved in the acquisition of new memories)2.
Along with the temporal lobe, traumatic experiences have consequences on other cortical areas. For instance, a study, in which magnetic resonances of abused children and adolescents were collected, found cortical atrophy and the enlargement of brain ventricles (large ventricles usually indicate a reduction in the cerebral cortex’s volume) in these subjects. The authors of the research, observed in participants suffering from post-traumatic stress, a reduction of the prefrontal cortex, the temporal lobe and the corpus callosum3. The reduction of the volume of frontal areas may be related to interferences in the ability to plan responses to new, non-stereotyped situations, more specifically to impairments in the ability to evaluate and react to external threats.
These problems, which are linked to the elaboration of trauma and of the adverse situations that may occur after the triggering traumatic experience, lead victims of severe traumas to an inevitable difficulty in the establishment of helping relationships with mental healthcare professionals. In fact, it seems that in people suffering from Post-Traumatic Stress Disorder (PTSD), the Broca area, located in the left frontal lobe, is less active compared to that of who never experienced traumatic events4. This area, among the most studied in the field of neuroscience, is classically defined as the language area because it is involved in linguistic production. Damages to this area can lead to communication difficulties and to the development of anxious responses in situations in which the verbalization of a traumatic memory is explicitly requested.
Despite that, it seems that psychotherapy can act on the same frontal areas that are struck by traumas, strengthening them. Thanks to functional magnetic resonance, in fact, it has been possible to demonstrate that, after only 16 sessions, patients suffering from PTSD, besides a subjective feeling of improvement, showed a decreased activation of frontal areas, which were hyperactive before therapy5.
In conclusion, the establishment of a helping relationship seems to be useful in treating post-traumatic conditions and in recovering fundamental functions, both psychological and relational, for the well being of the individual.
Bibliography
| 1. | Sweeney, Daniel. “The Neurobiology of Psychic Trauma and Treatment Considerations. ” Christian Counseling Connection, 2007. |
| 2. | McIntyre, Christa K, Teiko Miyashita, Barry Setlow, Kristopher D Marjon, Oswald Steward, John F Guzowski, and James L McGaugh. “Memory-influencing intra-basolateral amygdala drug infusions modulate expression of Arc protein in the hippocampus.” Proceedings of the National Academy of Sciences of the United States of America 102, no. 30 (July 26, 2005): 10718–10723. doi:10.1073/pnas.0504436102. |
| 3. | De Bellis, Michael D., Matcheri S. Keshavan, Heather Shifflett, Satish Iyengar, Sue R. Beers, Julie Hall, and Grace Moritz. “Brain Structures in Pediatric Maltreatment-related Posttraumatic Stress Disorder: a Sociodemographically Matched Study.” Biological Psychiatry 52, no. 11 (December 1, 2002): 1066–1078. doi:10.1016/S0006-3223(02)01459-2. |
| 4. | Rauch, S L, B A van der Kolk, R E Fisler, N M Alpert, S P Orr, C R Savage, A J Fischman, M A Jenike, and R K Pitman. “A symptom provocation study of posttraumatic stress disorder using positron emission tomography and script-driven imagery.” Archives of general psychiatry 53, no. 5 (May 1996): 380–387. |
| 5. | Lindauer, R J L, J Booij, J B A Habraken, E P M van Meijel, H B M Uylings, M Olff, I V E Carlier, G J den Heeten, B L F van Eck-Smit, and B P R Gersons. “Effects of psychotherapy on regional cerebral blood flow during trauma imagery in patients with post-traumatic stress disorder: a randomized clinical trial.” Psychological medicine 38, no. 4 (April 2008): 543–554. doi:10.1017/S0033291707001432. |
