1. Study suggests pregnant women with PTSD have higher levels of stress hormone cortisol

    December 14, 2017 by Ashley

    From the University of Michigan press release:

    Research has shown that a woman’s emotional and physical health during pregnancy impacts a developing fetus. However, less is known about the effect of past stressors and posttraumatic stress disorder on an expectant woman.

    To that end, researchers at the University of Michigan measured the stress hormone cortisol in pregnant women from early pregnancy to when their baby was 6 weeks old. They found that those with a dissociative type of PTSD that’s often related to childhood abuse or trauma had levels up to 10 times higher than their peers.

    These toxic levels of cortisol may contribute to health problems in the next generation, said Julia Seng, professor of nursing and lead author on the study.

    “We know from research on the developmental origins of health and disease that the baby’s first environment in its mother’s body has implications for health across the lifespan,” Seng said. “Higher exposure to cortisol may signal the fetus to adapt in ways that help survival, but don’t help health and longevity. This finding is very useful because it helps us know which women are most likely to exhibit the highest level of stress and stress hormones during pregnancy and postpartum.”

    Cortisol is sometimes called the stress hormone because it’s released in stressful situations as part of the flight-or-fight response. Cortisol levels that stay high are linked to serious health problems such as heart disease and high blood pressure, and can fuel weight gain, depression and anxiety plus a host of other problems. The effect of elevated cortisol on a developing fetus isn’t well understood, but high cortisol and stress also contribute to preterm birth.

    In the study, 395 women expecting their first child were divided into four groups: those without trauma, those with a trauma but no PTSD, those with classic PTSD and those with dissociative PTSD.

    Researchers measured salivary cortisol at different times during the day. Then 111 of those women gave saliva specimens until postpartum. The difference in cortisol was greatest in early pregnancy, when levels were eight times higher in the afternoon and 10 times higher at bedtime for the dissociative group than for other women.

    About 8 percent of pregnant women in the study had PTSD, a disorder that results when symptoms of anxiety and fear persist well after exposure to stressful events. About 14 percent of that group had the more complex dissociative PTSD, which was associated with higher cortisol.

    “It’s been a mystery in our field why cortisol is sometimes high with PTSD and sometimes not,” Seng said. “This finding that in pregnancy it’s only the dissociative subgroup that has high cortisol gives us more to go on for future research.”

    Seng was surprised at how high the cortisol was in the dissociative group. She also said researchers expected women with classic PTSD to experience elevated cortisol as well, and the fact that they didn’t is good news.

    “We can do something for the 1-to-2 out of 100 pregnant women who have this dissociative PTSD,” Seng said. “We can work with them to make pregnancy, maternity care, labor, breastfeeding and early parenting less likely to trigger stress reactions. And we can connect them to mental health services when they are ready to treat their PTSD.”

    Seng and collaborator Mickey Sperlich have developed a PTSD-specific education program for pregnant woman with a childhood trauma called the Survivor Moms’ Companion, which has been piloted in Michigan and is currently being piloted in England.


  2. Study suggests many cancer survivors are living with PTSD

    November 29, 2017 by Ashley

    From the Wiley press release:

    A recent study showed approximately one-fifth of patients with cancer experienced post-traumatic stress disorder (PTSD) several months after diagnosis, and many of these patients continued to live with PTSD years later. Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the findings highlight the need for early identification, careful monitoring, and treatment of PTSD in cancer survivors.

    Although PTSD is primarily known to develop in individuals following a traumatic event such as a serious accident or natural disaster, it can also occur in patients diagnosed with cancer. Because PTSD in cancer has not been explored thoroughly, Caryn Mei Hsien Chan, PhD, of the National University of Malaysia, and her colleagues studied 469 adults with various cancer types within one month of diagnosis at a single oncology referral center. Patients underwent additional testing after six months and again after four years.

    Clinical evaluations revealed a PTSD incidence of 21.7% at 6-months follow-up, with rates dropping to 6.1% at 4-years follow-up. Although overall rates of PTSD decreased with time, roughly one-third of patients initially diagnosed with PTSD were found to have persistent or worsening symptoms four years later.

    “Many cancer patients believe they need to adopt a ‘warrior mentality’, and remain positive and optimistic from diagnosis through treatment to stand a better chance of beating their cancer. To these patients, seeking help for the emotional issues they face is akin to admitting weakness,” said Dr. Chan. “There needs to be greater awareness that there is nothing wrong with getting help to manage the emotional upheaval — particularly depression, anxiety, and PTSD — post-cancer.”

    Dr. Chan also stressed that many patients live in fear that their cancer may come back, and they may think the cancer has returned with every lump or bump, pain or ache, fatigue or fever. In addition, survivors might skip visits to their oncologists or other physicians to avoid triggering memories of their past cancer experience. This can lead to delays in seeking help for new symptoms or even refusal of treatment for unrelated conditions.

    The researchers’ study also found that, compared with patients with other cancer types, patients with breast cancer were 3.7 times less likely to develop PTSD at six months, but not at four years. This may be because, at the referral center studied, there is a dedicated program that provides support and counselling, focusing mostly on breast cancer patients within the first year of cancer diagnosis.

    “We need psychological evaluation and support services for patients with cancer at an initial stage and at continued follows-up because psychological well-being and mental health — and by extension, quality of life — are just as important as physical health,” said Dr. Chan.


  3. Researchers develop psychotherapy treatment for refugees’ trauma

    November 13, 2017 by Ashley

    From the Bielefeld University press release:

    They are suffering from nightmares, flashbacks, depression, or anxiety disorders: refugees coming to Germany from conflict areas are frequently traumatized. ‘Realistic estimates state that up to 40 per cent of refugees have mental problems. Hence, for the period since 2015, we are talking about several hundred thousand people who are in real need of psychological support,’ says Professor Dr. Frank Neuner from Bielefeld University. The psychologist is one of the team responsible for developing ‘Narrative Exposure Therapy’ (NET). It has been applied over the last 15 years in conflict zones from East Africa to Sri Lanka. What is special about this therapy is that it shows success after only a few sessions. In a new ‘research_tv’ programme at Bielefeld University, Frank Neuner talks about NET and explains the consequences of leaving refugees without treatment.

    ‘I believe that a large part of the general population is willing to accept that we now need to invest substantially in dealing with these traumatized refugees and that the state must make money available for this,’ says Frank Neuner. ‘Due to the threats in their home countries, many refugees will be staying with us for a long time. By helping them now, we shall be warding off problems that will otherwise confront us unavoidably in 20 or 30 years time.’

    Neuner designed and tested NET together with Dr. Maggie Schauer and Professor Dr. Thomas Elbert from the University of Konstanz. By working with this method, hundreds of child soldiers, victims of political violence, and war refugees have been able to process their traumatic experiences.

    The key principle of NET is a highly valued practice in every culture: telling stories. ‘Whenever we have gone through an emotional experience, we try to tell stories. This is how we try to make what we have experienced comprehensible to others,’ says Neuner. ‘Refugees have experienced a whole series of traumatic events. We talk together with them about their entire life history and build up a kind of autobiography that enables them to embed the single traumatic experiences in a meaningful context and work out the significance they have in their own personal lives.’ Together with their therapist, traumatized persons work their way repeatedly and chronologically through the negative and positive events in their lives. ‘The idea is to historicize the traumatic events. This permits closure, so that they no longer threaten the present.’

    To deliver therapy to people in crisis zones, Neuner together with colleagues from the University of Konstanz and further supporters founded the aid organisation ‘Vivo’. It is training lay therapists in countries such as Sri Lanka, Ruanda, Uganda, and the Congo. Unlike Germany, the health systems of these countries do not provide access to professional therapists. ‘However, even Germany does not have enough therapists to treat all the refugees with traumatic disorders. Many people in Germany already have to wait months for a treatment slot with a therapist,’ says Neuner. ‘One step towards a solution could be to give NET training to refugees and migrants here in Germany and to employ them within a stepped care model supervised by psychotherapists. However, the German legal situation does not permit this at present.’

    NET is already being practiced by professional therapists in Germany. Bielefeld University’s psychotherapy clinic is applying the method in therapy studies not only refugees with but also with survivors of child abuse, rape victims, and former members of the German military. The scientific further education centres at Bielefeld University and the University of Konstanz are qualifying psychologists, medical doctors, and psychotherapists to work with NET.


  4. Locus coeruleus activity linked with hyperarousal in PTSD

    November 9, 2017 by Ashley

    From the Elsevier press release:

    A new study in Biological Psychiatry has linked signs of heightened arousal and reactivity — a core symptom of posttraumatic stress disorder (PTSD) — to overactivity of the locus coeruleus (LC), a brain region that mediates arousal and reactivity. By combining bodily responses and brain imaging data, the new paper by Dr. Christoph Mueller-Pfeiffer at the University of Zurich, Switzerland and colleagues is the first to provide direct human evidence for a theory over 30 years old. Pinpointing the origin of symptoms in the brain is a major step in efforts to improve treatment options for patients with the disorder.

    “The authors are to be congratulated on imaging this part of the brain,” said Dr. John Krystal, Editor of Biological Psychiatry. “Demonstrating the presence of LC hyperactivity in PTSD sets the stage for clarifying the relationship of LC activity to stress response, resilience, PTSD symptoms, and the treatment of PTSD,” he added.

    In the study, first author Christoph Naegeli, also of University of Zurich, and colleagues analyzed 54 participants who had been exposed to trauma, about half of whom developed PTSD. When the participants listened to random bursts of white noise, those who were diagnosed with PTSD had more frequent eye blinks, and increased heart rate, skin conductance and pupil area responses — indicators of the body’s autonomic response — than participants without PTSD.

    Using functional magnetic resonance imaging to measure brain activity, Naegeli and colleagues found that patients with PTSD had larger brain responses in the LC and other regions wired to the LC that control alertness and motor preparation. According to Mueller-Pfeiffer, the increased brain activity and autonomic responses measured in the participants provide a biologically plausible explanation for hypervigilance and exaggerated startle responses in PTSD. However, LC activation was not directly associated with arousal symptoms. Thus, direct links between LC hyperactivity and PTSD symptom severity still need to be demonstrated.

    The study may also reveal new avenues for treating these common and disabling symptoms of PTSD. “Our results suggest that targeting locus coeruleus system hyperactivity with new pharmacological or psychotherapeutic interventions are approaches worthy of further investigation,” said Dr. Mueller-Pfeiffer.


  5. Study identifies mechanism that helps us inhibit unwanted thoughts

    November 5, 2017 by Ashley

    From the University of Cambridge press release:

    Scientists have identified a key chemical within the ‘memory’ region of the brain that allows us to suppress unwanted thoughts, helping explain why people who suffer from disorders such as anxiety, post-traumatic stress disorder (PTSD), depression, and schizophrenia often experience persistent intrusive thoughts when these circuits go awry.

    We are sometimes confronted with reminders of unwanted thoughts — thoughts about unpleasant memories, images or worries. When this happens, the thought may be retrieved, making us think about it again even though we prefer not to. While being reminded in this way may not be a problem when our thoughts are positive, if the topic was unpleasant or traumatic, our thoughts may be very negative, worrying or ruminating about what happened, taking us back to the event.

    “Our ability to control our thoughts is fundamental to our wellbeing,” explains Professor Michael Anderson from the Medical Research Council Cognition and Brain Sciences Unit at the University of Cambridge. “When this capacity breaks down, it causes some of the most debilitating symptoms of psychiatric diseases: intrusive memories, images, hallucinations, ruminations, and pathological and persistent worries. These are all key symptoms of mental illnesses such as PTSD, schizophrenia, depression, and anxiety.”

    Professor Anderson likens our ability to intervene and stop ourselves retrieving particular memories and thoughts to stopping a physical action. “We wouldn’t be able to survive without controlling our actions,” he says. “We have lots of quick reflexes that are often useful, but we sometimes need to control these actions and stop them from happening. There must be a similar mechanism for helping us stop unwanted thoughts from occurring.”

    A region at the front of the brain known as the prefrontal cortex is known to play a key role in controlling our actions and has more recently been shown to play a similarly important role in stopping our thoughts. The prefrontal cortex acts as a master regulator, controlling other brain regions — the motor cortex for actions and the hippocampus for memories.

    In research published today in the journal Nature Communications, a team of scientists led by Dr Taylor Schmitz and Professor Anderson used a task known as the ‘Think/No-Think’ procedure to identify a significant new brain process that enables the prefrontal cortex to successfully inhibit our thoughts.

    In the task, participants learn to associate a series of words with a paired, but otherwise unconnected, word, for example ordeal/roach and moss/north. In the next stage, participants are asked to recall the associated word if the cue is green or to suppress it if the cue is red; in other words, when shown ‘ordeal’ in red, they are asked to stare at the word but to stop themselves thinking about the associated thought ‘roach’.

    Using a combination of functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy, the researchers were able to observe what was happening within key regions of the brain as the participants tried to inhibit their thoughts. Spectroscopy enabled the researchers to measure brain chemistry, and not just brain activity, as is usually done in imaging studies.

    Professor Anderson, Dr Schmitz and colleagues showed that the ability to inhibit unwanted thoughts relies on a neurotransmitter — a chemical within the brain that allows messages to pass between nerve cells — known as GABA. GABA is the main ‘inhibitory’ neurotransmitter in the brain, and its release by one nerve cell can suppress activity in other cells to which it is connected. Anderson and colleagues discovered that GABA concentrations within the hippocampus — a key area of the brain involved in memory — predict people’s ability to block the retrieval process and prevent thoughts and memories from returning.

    “What’s exciting about this is that now we’re getting very specific,” he explains. “Before, we could only say ‘this part of the brain acts on that part’, but now we can say which neurotransmitters are likely important — and as a result, infer the role of inhibitory neurons — in enabling us to stop unwanted thoughts.”

    “Where previous research has focused on the prefrontal cortex — the command centre — we’ve shown that this is an incomplete picture. Inhibiting unwanted thoughts is as much about the cells within the hippocampus — the ‘boots on the ground’ that receive commands from the prefrontal cortex. If an army’s foot-soldiers are poorly equipped, then its commanders’ orders cannot be implemented well.”

    The researchers found that even within his sample of healthy young adults, people with less hippocampal GABA (less effective ‘foot-soldiers’) were less able to suppress hippocampal activity by the prefrontal cortex — and as a result much worse at inhibiting unwanted thoughts.

    The discovery may answer one of the long-standing questions about schizophrenia. Research has shown that people affected by schizophrenia have ‘hyperactive’ hippocampi, which correlates with intrusive symptoms such as hallucinations. Post-mortem studies have revealed that the inhibitory neurons (which use GABA) in the hippocampi of these individuals are compromised, possibly making it harder for the prefrontal cortex to regulate activity in this structure. This suggests that the hippocampus is failing to inhibit errant thoughts and memories, which may be manifest as hallucinations.

    According to Dr Schmitz, “The environmental and genetic influences that give rise to hyperactivity in the hippocampus might underlie a range of disorders with intrusive thoughts as a common symptom.”

    In fact, studies have shown that elevated activity in the hippocampus is seen in a broad range of conditions such as PTSD, anxiety and chronic depression, all of which include a pathological inability to control thoughts — such as excessive worrying or rumination.

    While the study does not examine any immediate treatments, Professor Anderson believes it could offer a new approach to tackling intrusive thoughts in these disorders. “Most of the focus has been on improving functioning of the prefrontal cortex,” he says, “but our study suggests that if you could improve GABA activity within the hippocampus, this may help people to stop unwanted and intrusive thoughts.”

    The research was funded by the Medical Research Council.


  6. Study suggests that brain region for balance, movement also involved in processing traumatic memories

    October 29, 2017 by Ashley

    From the Thomas Jefferson University press release:

    Patients diagnosed and treated for a long-term potentially fatal diseases such as cancer, can accumulate distressing and traumatic experiences along the way. A new study from the Marcus Institute of Integrative Health at Thomas Jefferson University examines how the brain is activated when the Neuro Emotional Technique (NET) is used to help cancer patients process traumatic memories. The research, published in the Journal of Cancer Survivorship, also adds to the basic understanding of the pathophysiology of traumatic stress in general and the underlying mechanisms involved with resolving it.

    “The results of this study are a breakthrough in understanding how an intervention like NET works, particularly in regard to the cerebellum’s role in the regulation of emotional experiences. We now understand that the cerebellum does much more than coordinate motor activity,” said principal investigator Daniel Monti, MD, MBA, Director of the Marcus Institute of Integrative Health who is also a member of the Sidney Kimmel Cancer Center at Jefferson.

    The intervention, Neuro Emotional Technique (NET), is unique in allowing the practitioner to not only gauge the patient’s subjective distress but also how the nervous system is reacting to that stress, using biofeedback tools. This provides information that is not usually part of standard interventions, and is what potentially makes NET an especially efficient and efficacious therapeutic solution for traumatic stress. By showing the link between the cerebellum, limbic (emotional) centers, and autonomic nervous system, the present study expands current understanding of traumatic memories and how and intervention like NET can significantly alleviate the suffering associated with them.

    “This is the first study that offers a demonstrable solution for cancer patients with traumatic stress symptoms. It also expands our understanding of the importance of the cerebellum in coordinating traumatic emotions, and the body’s response to them,” said Dr. Monti.

    This new data suggests that a brief therapeutic course of the NET intervention substantially alters the brain’s response to traumatic memories, and it elucidates the potential importance of the cerebellum in regulating the brain and body’s response to traumatic stress. (Previous research from the Marcus Institute demonstrated the efficacy of the NET intervention for relieving stress in cancer patients.)

    “Just four to five brief NET sessions result in significantly less emotional and physical distress, and these improvements are associated with connectivity changes throughout the brain,” said Dr. Monti. “Patients, even those who were skeptical at first, have reported the NET intervention as ‘diffusing a bomb’ on ‘the worst anxiety ever.'”


  7. Study suggests rapid eye movement sleep may dampen sensitivity to fearful stimuli

    October 27, 2017 by Ashley

    From the Society for Neuroscience press release:

    Higher quality sleep patterns are associated with reduced activity in brain regions involved in fear learning, according to a study of young adults published in JNeurosci. The results suggest that baseline sleep quality may be a useful predictor of susceptibility to post-traumatic stress disorder (PTSD).

    Sleep disturbances are a common feature of PTSD. While previous research has focused on understanding how single nights of sleep influence the maintenance of already-established fear memories, few studies have investigated whether an individual’s regular sleeping habits prior to trauma contributes to the acquisition of these fear memories.

    Itamar Lerner, Shira Lupkin and their colleagues at Rutgers University had students monitor their sleep at home for one week using unobtrusive sleep monitoring tools, including a headband that measures brain waves, a bracelet that measures arm movements, and a sleep log. The students then participated in a neuroimaging experiment during which they learned to associate a neutral image with a mild electric shock. Students who spent more time in rapid eye movement (REM) sleep — the phase when dreaming occurs — exhibited weaker modulation of activity in, and connectivity between, their amygdala, hippocampus and ventromedial prefrontal cortex during fear learning.

    The authors replicated these results in a second study using traditional polysomnographic monitoring of sleep during the night just prior to fear learning. Taken together, the findings are consistent with the idea that REM sleep reduces levels of norepinephrine in the brain, which may dampen an individual’s sensitivity to fearful stimuli.


  8. Study suggests predicting depression and PTSD before deployment could help soldiers cope

    October 17, 2017 by Ashley

    From the BioMed Central press release:

    A set of validated, self-reported questions administered early in a soldier’s career could predict mental health problems such as depression and post-traumatic stress disorder (PTSD) after return from deployment, according to a study published in the open access journal BMC Psychology.

    The questions assess 14 psychological attributes such as adaptability, coping ability and optimism. They could be used to identify high-risk individuals and provide them with psychological and social resources to help them cope with stressors of deployment including combat trauma and extended separation from friends and family, researchers at Naval Postgraduate School and Research Facilitation Laboratory, USA suggest.

    In addition to scoring psychological health attributes before deployment, the researchers also generated an individual, composite risk score for each soldier using baseline psychological attributes and demographic information such as gender, age, race/ethnicity, marital status, education, and military occupation group. They found that out of those whose score classified them as being at highest risk for psychological health disorders (i.e. at the top 5% of the score), 31% screened positive for depression, while 27% screened positive for PTSD after return from deployment.

    Professor Yu-Chu Shen, lead author of the study said: “We found that soldiers who had the worst pre-military psychological health attribute scores — those in the bottom 5% of scores — carried much higher odds of screening positive for depression and PTSD after returning home than the top 95%. Soldiers who score worst before deployment might be more susceptible to developing debilitating mental health disorders when they are later exposed to combat environments.”

    The findings suggest that psychological screening before deployment, in combination with other personnel information, can be helpful in identifying individuals who carry significant risk for psychological health disorders, according to the authors. Being aware of this risk could enable tailored interventions to increase soldiers’ psychological health prior to exposing them to combat. Identifying individuals at risk of adverse psychological outcomes could also translate into savings on costs resulting from treatment and lost productivity.

    To investigate the association of psychological attributes in soldiers before deployment and their risk for depression and PTSD after their return, the authors used data from three sources on 63,138 soldiers who enlisted after 2008: the Army’s personnel database, pre- and post-deployment health assessments, and the Global Assessment Tool (GAT).

    GAT is an annual resilience and psychological health assessment completed by all members of the US Army. It consists of a 105-item questionnaire that captures 14 attributes of health and resilience that are considered important for life in the military. These attributes include optimism and catastrophizing, which may reflect how a person responds to the stress of combat; positive affect and organisational trust, which capture how a person may respond to leadership; and resilience and coping ability.

    The authors caution that GAT in its current form is not designed to be used as a screening tool on which employment decisions should be based.

    Professor Shen said: “In this study, we illustrate the potential value for psychological health screening such as GAT in public safety and national defense occupations. However, for any strategy based on screenings like this to be successful and effective, we also highlight the importance for future screening tools to be designed to detect and minimize strategic responding — that is personnel adapting their answers if they know that their career progression and chance of deployment may depend on their screening scores. Strategic responding may undermine the effectiveness of a screening tool in identifying the risk for mental health disorders.”


  9. Study explains why stress hormone can prevent disorders after exposure to traumatic event

    September 25, 2017 by Ashley

    From the Universitat Autònoma de Barcelona press release:

    People who have suffered from traffic accidents, war combat, terrorist attacks and exposure to other traumatic events have an increased likelihood of developing diseases. These diseases can be psychological and physical, such as heart problems and cancer. The current preventive treatments based on psychological support and drugs are effective in some cases. Unfortunately, these treatments do not work for many individuals. It is also known that the earlier the treatment starts the better to prevent future negative consequences.

    Researchers at the Institut de Neurociències of the Universitat Autònoma de Barcelona (INc-UAB, Spain) have discovered in a study with mice and humans that the Ppm1f (Protein phosphatase 1f) gene expression is one of the most highly regulated after exposure to traumatic stress. Moreover, Ppm1f is associated with posttraumatic stress disorder (PTSD), depression and anxiety. The main function of Ppm1f is to regulate the activity of the protein Camk2 (Calmodulin-dependent protein kinase 2), which is key in many processes of the human body such as memory, the heart’s functioning and the immune system.

    According to Dr. Raül Andero Galí, lead researcher in this study, “Once we discovered the relationship between the Ppm1f gene and different psychological disorders after exposure to traumatic stress, we wanted to find an effective drug to prevent these changes and its negative consequences on the brain.” Dr Andero is scientist at the INc-UAB. It was already known that dosing the stress hormone — a glucocorticoid — few hours after exposure to a traumatic event may decrease the likelihood of developing psychological disorders. Thus, the scientists administered the hormone to mice one hour after exposure to stress. “The results confirmed a decrease in the symptoms of anxiety and depression, and also that this effect is because the Ppm1f gene changes are prevented,” explains Dr. Eric Velasco, researcher at the INc-UAB and co-author of the study.

    “The apparent contradiction that the stress hormone decreases the likelihood of developing diseases after exposure to traumatic stress is one of the greatest paradoxes of current medicine” Andero says. “This study sheds light on this paradox and uncovers a way by which the stress hormone could prevent diseases, at least psychologically, through regulation of the Ppm1f gene” he adds.

    Until now, the stress hormone has been administered to people in very few cases. “Our discovery opens the door to a broader application and to the development of treatments aimed specifically at regulating this gene’s functions,” says Antonio Florido, researcher of the INc-UAB and also co-author of the paper.

    The study was carried out in collaboration with the universities of Harvard and Emory (United States). This work is published in Biological Psychiatry, one of the most important journals in Neuroscience. The UAB researchers are currently interested in collaborating with other laboratories and obtaining funding to continue the studies of Ppm1f associated with other disorders such as cardiovascular diseases and cancer in order to verify whether their results are comparable in other diseases and potentially prevent them.


  10. How particular fear memories can be erased

    September 2, 2017 by Ashley

    From the University of California – Riverside press release:

    Researchers at the University of California, Riverside have devised a method to selectively erase particular fear memories by weakening the connections between the nerve cells (neurons) involved in forming these memories.

    A sight, sound, or smell we have sensed may not later trigger fear, but if the stimulus is associated with a traumatic event, such as a car accident, then fear memory is formed, and fearful responses are triggered by the stimulus.

    To survive in a dynamic environment, animals develop fear responses to dangerous situations. But not all fear memories, such as those in PTSD, are beneficial to our survival. For example, while an extremely fearful response to the sight of a helicopter is not a useful one for a war veteran, a quick reaction to the sound of a gunshot is still desirable. For survivors of car accidents, it would not be beneficial for them to relive the trauma each time they sit in a car.

    In their lab experiments, Jun-Hyeong Cho, M.D., Ph.D., an assistant professor of molecular, cell, and systems biology, and Woong Bin Kim, his postdoctoral researcher, found that fear memory can be manipulated in such a way that some beneficial memories are retained while others, detrimental to our daily life, are suppressed.

    The research, done using a mouse model and published today in Neuron, offers insights into how PTSD and specific phobias may be better treated.

    “In the brain, neurons communicate with each other through synaptic connections, in which signals from one neuron are transmitted to another neuron by means of neurotransmitters,” said Cho, who led the research. “We demonstrated that the formation of fear memory associated with a specific auditory cue involves selective strengthening in synaptic connections which convey the auditory signals to the amygdala, a brain area essential for fear learning and memory. We also demonstrated that selective weakening of the connections erased fear memory for the auditory cue.”

    In the lab, Cho and Kim exposed mice to two sounds: a high-pitch tone and a low-pitch tone. Neither tone produced a fear response in the mice. Next, they paired only the high-pitched tone with a mild footshock administered to the mice. Following this, Cho and Kim again exposed the mice to the two tones. To the high-pitch tone (with no accompanying footshock), the mice responded by ceasing all movement, called freezing behavior. The mice showed no such response to the low-pitch sound (with no accompanying footshock). The researchers found that such behavioral training strengthened synaptic connections that relay the high-pitch tone signals to the amygdala.

    The researchers then used a method called optogenetics to weaken the synaptic connection with light, which erased the fear memory for the high-pitch tone.

    “In the brain, neurons receiving the high- and low-pitch tone signals are intermingled,” said Cho, a member of the Center for Glial-Neuronal Interactions in the UC Riverside School of Medicine. “We were able, however, to experimentally stimulate just those neurons that responded to the high-pitch sound. Using low-frequency stimulations with light, we were able to erase the fear memory by artificially weakening the connections conveying the signals of the sensory cue — a high-pitch tone in our experiments — that are associated with the aversive event, namely, the footshock.”

    Cho explained that for adaptive fear responses to be developed, the brain must discriminate between different sensory cues and associate only relevant stimuli with aversive events.

    “This study expands our understanding of how adaptive fear memory for a relevant stimulus is encoded in the brain,” he said. “It is also applicable to developing a novel intervention to selectively suppress pathological fear while preserving adaptive fear in PTSD.”

    The researchers note that their method can be adapted for other research, such as “reward learning” where stimulus is paired with reward. They plan next to study the mechanisms involved in reward learning which has implications in treating addictive behaviors.

    The research, which builds on earlier work by Cho and Kim, was funded by the Initial Complement Funds to Cho from UCR.