Extracellular matrix: a new player in memory maintenance and psychiatric disorders

How the brain performs higher cognitive functions such as learning and memory is traditionally studied by investigating how neurons work. However, over the past two decades, evidence has accumulated which suggests that components of the extracellular matrix contribute to the storing of information through learning processes. Thus, matrix regulation – either changes in the protein composition of the perineural network surrounding neurons or cleavage of this network by specific metalloproteases – could be relevant to the many psychiatric disorders that are shaped by previous experiences, i.e. by learning and plasticity. This includes disorders which are a direct consequence of past experiences and ones where previous experiences constitute a risk factor. Psychotherapy is one of the first-line treatments for most psychiatric conditions, and involves learning and plasticity. Here, we review selected publications pertaining to experience dependence in psychiatric conditions and summarise evidence of roles for the extracellular matrix in learning and memory. We then suggest how control of the extracellular matrix could be leveraged for innovative treatments and, more generally, discuss possible aetiological effects of extracellular matrix alterations in psychiatric disorders

Perceptual processing advantages for trauma-related visual cues in post-traumatic stress disorder

BACKGROUND: Intrusive re-experiencing in post-traumatic stress disorder (PTSD) comprises distressing sensory impressions from the trauma that seem to occur 'out of the blue'. A key question is how intrusions are triggered. One possibility is that PTSD is characterized by a processing advantage for stimuli that resemble those that accompanied the trauma, which would lead to increased detection of such cues in the environment. METHOD: We used a blurred picture identification task in a cross-sectional (n=99) and a prospective study (n=221) of trauma survivors. RESULTS: Participants with acute stress disorder (ASD) or PTSD, but not trauma survivors without these disorders, identified trauma-related pictures, but not general threat pictures, better than neutral pictures. There were no group differences in the rate of trauma-related answers to other picture categories. The relative processing advantage for trauma-related pictures correlated with re-experiencing and dissociation, and predicted PTSD at follow-up. CONCLUSIONS: A perceptual processing bias for trauma-related stimuli may contribute to the involuntary triggering of intrusive trauma memories in PTSD

Early Linguistic Markers of Trauma-Specific Processing Predict Post-trauma Adjustment

Identifying early predictors for psychiatric disorders, such as post-traumatic stress disorder (PTSD), is crucial for effective treatment and prevention efforts. Obtaining such predictors is challenging and methodologically limited, for example by individuals' distress, arousal, and reduced introspective ability. We investigated the predictive power of language-based, implicit markers of psychological processes (N = 163) derived from computerized text-analysis of trauma and control narratives provided within 18 days post-trauma. Trauma narratives with fewer cognitive processing words (indicating less cognitive elaboration), more death-related words (indicating perceived threat to life), and more first-person singular pronouns (indicating self-immersed processing) predicted greater PTSD symptoms at 6 months. These effects were specific to trauma narratives and held after controlling for early PTSD symptom severity and verbal intelligence. When self-report questionnaires of related processes were considered together with the trauma narrative linguistic predictors, use of more first-person singular pronouns remained a significant predictor alongside self-reported mental defeat. Language-based processing markers may complement questionnaire measures in early forecasting of post-trauma adjustment

Do alpine skiers and snowboarders wear protective equipment more often after an accident?

Questions under study/principles: Analysis of changes in the behaviour of wearing protective equipment by alpine skiers and snowboarders after injury, performed at a level I trauma centre in Switzerland. Methods: We present a study, using a standardised questionnaire, assessing behaviour on ski slopes by adult patients admitted between Oct 2007 and April 2008. Patients were re-interviewed after the 2008/2009 season. McNemar tests were used to analyse differences in protective clothing wearing rates between the two seasons. Multiple logistic regression with age, gender and injury severity score (ISS) as predictors, was used to compare findings in those who started wearing protective equipment and those who did not. Results: A total of 104/132 patients from the 2007/2008 season were questioned about wearing protective equipment in 2008/2009. 20 patients could not be reassessed (7 declined, 13 had abandoned winter sports). A total of 84 patients were reassessed (61 alpine skiers and 23 snowboarders). The median age of participants was 39 years and 70.2% were male. Helmet and back protector wearing rates increased from 40.5% to 78.6% (p <0.001) and from 14.3% to 23.8% (p = 0.021), respectively. Snowboarders more than doubled their helmet wearing rate (39.1% to 82.6%, p = 0.002). Skiers showed a trend towards doubling their back protector wearing rate (6.6% to 14.8%, p = 0.063). Younger skiers started wearing back protectors more often than older skiers. Conclusions: Sustained injury might provide skiers and snowboards with a potent trigger to change their attitude towards the use of protective equipment. The psychological processes influencing the use of protective equipment require further investigation

All-suture anchors for distal biceps tendon repair: a preliminary outcome study

Introduction: The aim of this study was to retrospectively evaluate the clinical outcome of double intramedullary all-suture anchors’ fixation for distal biceps tendon ruptures. Materials and methods: A retrospective case series of patients who underwent primary distal biceps tendon repair with all-suture anchors was conducted. Functional outcome was assessed at a minimum follow-up of at 12 months based on the assessments of the Mayo Elbow Performance Score (MEPS), Andrews–Carson Score (ACS), Quick Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), and the Visual Analog Scale (VAS) for pain. Maximum isometric strength test for flexion and supination as well as postoperative range of motion (ROM) were determined for both arms. Results: 23 patients treated with all-suture anchors were assessed at follow-up survey (mean age 56.5 ± 11.4 years, 96% male). The follow-up time was 20 months (range Q$_{0.25}$–Q$_{0.75}$, 15–23 months). The following outcome results were obtained: MEPS 100 (range Q$_{0.25}$–Q$_{0.75}$, 100–100); ACS 200 (range Q$_{0.25}$–Q$_{0.75}$, 195–200); QuickDASH 31 (range Q$_{0.25}$–Q$_{0.75}$, 30–31); VAS 0 (range Q$_{0.25}$–Q$_{0.75}$, 0–0). The mean strength compared to the uninjured side was 95.6% (range Q$_{0.25}$–Q$_{0.75}$, 80.9–104%) for flexion and 91.8 ± 11.6% for supination. There was no significant difference in ROM or strength compared to the uninjured side and no complications were observed in any patient. Conclusion: Distal biceps tendon refixation using all-suture anchors provides good-to-excellent results in terms of patient-reported and functional outcome. This repair technique appears to be a viable surgical option, although further long-term results are needed

Perceived responsiveness in suicidal ideation: An experience sampling study in psychiatric patients

Introduction: Perceived responsiveness, or the extent to which one feels understood, validated and cared for by close others, plays a crucial role in people's well‐being. Can this interpersonal process also protect people at risk? We assessed whether fluctuations in suicidal ideation were associated with fluctuations in the degree of perceived responsiveness that psychiatric patients (admitted in the context of suicide or indicating suicidal ideation) experienced in daily interactions immediately after discharge. Methods: Fifty‐seven patients reported on suicidal ideation (5 times a day) and perceived responsiveness (daily) for four consecutive weeks. The effects of established risk factors—thwarted belongingness, perceived burdensomeness, and hopelessness—were assessed as well. Results: The more patients felt that close others had been responsive to them, the less suicidal ideation they reported. At low levels of thwarted belongingness, perceived burdensomeness, or hopelessness, perceived responsiveness seemed to play a protective role, negatively co‐occurring with suicidal ideation. When thwarted belongingness, perceived burdensomeness, and hopelessness were high, perceived responsiveness did not have an effect. Conclusion: Perceived responsiveness could be a protective factor for suicidal ideation for people at risk only when they are experiencing low levels of negative perceptions. When experiencing highly negative perceptions, however, perceived responsiveness seems to matter less

Systematic assessment of training-induced changes in corticospinal output to hand using frameless stereotaxic transcranial magnetic stimulation.

Measuring changes in the characteristics of corticospinal output has become a critical part of assessing the impact of motor experience on cortical organization in both the intact and injured human brain. In this protocol we describe a method for systematically assessing training-induced changes in corticospinal output that integrates volumetric anatomical MRI with transcranial magnetic stimulation (TMS). A TMS coil is sited to a target grid superimposed onto a 3D MRI of cortex using a stereotaxic neuronavigation system. Subjects are then required to exercise the first dorsal interosseus (FDI) muscle on two different tasks for a total of 30 min. The protocol allows for reliably and repeatedly detecting changes in corticospinal output to FDI muscle in response to brief periods of motor training

Sleep enhances exposure therapy

Background Sleep benefits memory consolidation. Here, we tested the beneficial effect of sleep on memory consolidation following exposure psychotherapy of phobic anxiety. Method A total of 40 individuals afflicted with spider phobia according to DSM-IV underwent a one-session virtual reality exposure treatment and either slept for 90min or stayed awake afterwards. Results Sleep following exposure therapy compared with wakefulness led to better reductions in self-reported fear (p=0.045, d=0.47) and catastrophic spider-related cognitions (p=0.026, d=0.53) during approaching a live spider, both tested after 1 week. Both reductions were associated with greater percentages of stage 2 sleep. Conclusions Our results indicate that sleep following successful psychotherapy, such as exposure therapy, improves therapeutic effectiveness, possibly by strengthening new non-fearful memory traces established during therapy. These findings offer an important non-invasive alternative to recent attempts to facilitate therapeutic memory extinction and consolidation processes with pharmacological or behavioral intervention