Learning to Obtain Reward, but Not Avoid Punishment, Is Affected by Presence of PTSD Symptoms in Male Veterans: Empirical Data and Computational Model

Post-traumatic stress disorder (PTSD) symptoms include behavioral avoidance which is acquired and tends to increase with time. This avoidance may represent a general learning bias; indeed, individuals with PTSD are often faster than controls on acquiring conditioned responses based on physiologically-aversive feedback. However, it is not clear whether this learning bias extends to cognitive feedback, or to learning from both reward and punishment. Here, male veterans with self-reported current, severe PTSD symptoms (PTSS group) or with few or no PTSD symptoms (control group) completed a probabilistic classification task that included both reward-based and punishment-based trials, where feedback could take the form of reward, punishment, or an ambiguous “no-feedback” outcome that could signal either successful avoidance of punishment or failure to obtain reward. The PTSS group outperformed the control group in total points obtained; the PTSS group specifically performed better than the control group on reward-based trials, with no difference on punishment-based trials. To better understand possible mechanisms underlying observed performance, we used a reinforcement learning model of the task, and applied maximum likelihood estimation techniques to derive estimated parameters describing individual participants’ behavior. Estimations of the reinforcement value of the no-feedback outcome were significantly greater in the control group than the PTSS group, suggesting that the control group was more likely to value this outcome as positively reinforcing (i.e., signaling successful avoidance of punishment). This is consistent with the control group’s generally poorer performance on reward trials, where reward feedback was to be obtained in preference to the no-feedback outcome. Differences in the interpretation of ambiguous feedback may contribute to the facilitated reinforcement learning often observed in PTSD patients, and may in turn provide new insight into how pathological behaviors are acquired and maintained in PTSD

ICDP workshop on the Deep Drilling in the Turkana Basin Project:Exploring the link between environmental factors and hominin evolution over the past 4 Myr

Scientific drill cores provide unique windows into the processes of the past and present. In the dynamic tectonic, environmental, climatic, and ecological setting that is eastern Africa, records recovered through scientific drilling enable us to look at change through time in unprecedented ways. Cores from the East African Rift System can provide valuable information about the context in which hominins evolved in one of the key regions of hominin evolution over the past 4 Myr. The Deep Drilling in the Turkana Basin (DDTB) project seeks to explore the impact of several types of evolution (tectonic, climatic, biological) on ecosystems and environments. This includes addressing questions regarding the region’s complex and interrelated rifting and magmatic history, as well as understanding processes of sedimentation and associated hydrothermal systems within the East African Rift System. We seek to determine the relative impacts of tectonic and climatic evolution on eastern African ecosystems. We ask, what role (if any) did climate change play in the evolution of hominins? How can our understanding of past environmental change guide our planning for a future shaped by anthropogenic climate change? To organize the scientific community’s goals for deep coring in the Turkana Basin, we hosted a 4-day ICDP supported workshop in Nairobi, Kenya in July 2022. The team focused on how a 4 Myr sedimentary core from the Turkana Basin will uniquely address key scientific research objectives related to basin evolution, paleoclimate, paleoenvironment, and modern resources. Participants also discussed how DDTB could collaborate with community partners in the Turkana Basin, particularly around the themes of access to water and education. The team concluded that collecting the proposed Pliocene to modern record is best accomplished through a 2-phase drilling project with a land-based transect of four cores spanning the interval from 4 Ma to Middle/Late Pleistocene (<0.7 Ma) and a lake-based core targeting the interval from ~1 Ma to present. The second phase, while logistically more challenging due to the lack of drilling infrastructure currently on Lake Turkana, would revolutionize our understanding of a significant interval in the evolution and migration of Homo sapiens for a time period not currently accessible from the Kenyan part of the Turkana Basin. Collectively, the DDTB project will provide exceptional tectonic and climatic data directly associated with one of the world’s richest hominin fossil localities

ICDP workshop on the Deep Drilling in the Turkana Basin Project:Exploring the link between environmental factors and hominin evolution over the past 4 Myr

Scientific drill cores provide unique windows into the processes of the past and present. In the dynamic tectonic, environmental, climatic, and ecological setting that is eastern Africa, records recovered through scientific drilling enable us to look at change through time in unprecedented ways. Cores from the East African Rift System can provide valuable information about the context in which hominins evolved in one of the key regions of hominin evolution over the past 4 Myr. The Deep Drilling in the Turkana Basin (DDTB) project seeks to explore the impact of several types of evolution (tectonic, climatic, biological) on ecosystems and environments. This includes addressing questions regarding the region’s complex and interrelated rifting and magmatic history, as well as understanding processes of sedimentation and associated hydrothermal systems within the East African Rift System. We seek to determine the relative impacts of tectonic and climatic evolution on eastern African ecosystems. We ask, what role (if any) did climate change play in the evolution of hominins? How can our understanding of past environmental change guide our planning for a future shaped by anthropogenic climate change? To organize the scientific community’s goals for deep coring in the Turkana Basin, we hosted a 4-day ICDP supported workshop in Nairobi, Kenya in July 2022. The team focused on how a 4 Myr sedimentary core from the Turkana Basin will uniquely address key scientific research objectives related to basin evolution, paleoclimate, paleoenvironment, and modern resources. Participants also discussed how DDTB could collaborate with community partners in the Turkana Basin, particularly around the themes of access to water and education. The team concluded that collecting the proposed Pliocene to modern record is best accomplished through a 2-phase drilling project with a land-based transect of four cores spanning the interval from 4 Ma to Middle/Late Pleistocene (<0.7 Ma) and a lake-based core targeting the interval from ~1 Ma to present. The second phase, while logistically more challenging due to the lack of drilling infrastructure currently on Lake Turkana, would revolutionize our understanding of a significant interval in the evolution and migration of Homo sapiens for a time period not currently accessible from the Kenyan part of the Turkana Basin. Collectively, the DDTB project will provide exceptional tectonic and climatic data directly associated with one of the world’s richest hominin fossil localities

Inhibited Personality Temperaments Translated Through Enhanced Avoidance and Associative Learning Increase Vulnerability for PTSD

Although many individuals who experience a trauma go on to develop post-traumatic stress disorder (PTSD), the rate of PTSD following trauma is only about 15–24%. There must be some pre-existing conditions that impart increased vulnerability to some individuals and not others. Diathesis models of PTSD theorize that pre-existing vulnerabilities interact with traumatic experiences to produce psychopathology. Recent work has indicated that personality factors such as behavioral inhibition (BI), harm avoidance (HA), and distressed (Type D) personality are vulnerability factors for the development of PTSD and anxiety disorders. These personality temperaments produce enhanced acquisition or maintenance of associations, especially avoidance, which is a criterion symptom of PTSD. In this review, we highlight the evidence for a relationship between these personality types and enhanced avoidance and associative learning, which may increase risk for the development of PTSD. First, we provide the evidence confirming a relationship among BI, HA, distressed (Type D) personality, and PTSD. Second, we present recent findings that BI is associated with enhanced avoidance learning in both humans and animal models. Third, we will review evidence that BI is also associated with enhanced eyeblink conditioning in both humans and animal models. Overall, data from both humans and animals suggest that these personality traits promote enhanced avoidance and associative learning, as well as slowing of extinction in some training protocols, which all support the learning diathesis model. These findings of enhanced learning in vulnerable individuals can be used to develop objective behavioral measures to pre-identify individuals who are more at risk for development of PTSD following traumatic events, allowing for early (possibly preventative) intervention, as well as suggesting possible therapies for PTSD targeted on remediating avoidance or associative learning. Future work should explore the neural substrates of enhanced avoidance and associative learning for behaviorally inhibited individuals in both the animal model and human participants

Orbital controls on eastern African hydroclimate in the Pleistocene

Understanding eastern African paleoclimate is critical for contextualizing early human evolution, adaptation, and dispersal, yet Pleistocene climate of this region and its governing mechanisms remain poorly understood due to the lack of long, orbitally-resolved, terrestrial paleoclimate records. Here we present leaf wax hydrogen isotope records of rainfall from paleolake sediment cores from key time windows that resolve long-term trends, variations, and high-latitude effects on tropical African precipitation. Eastern African rainfall was dominantly controlled by variations in low-latitude summer insolation during most of the early and middle Pleistocene, with little evidence that glacial–interglacial cycles impacted rainfall until the late Pleistocene. We observe the influence of high-latitude-driven climate processes emerging from the last interglacial (Marine Isotope Stage 5) to the present, an interval when glacial–interglacial cycles were strong and insolation forcing was weak. Our results demonstrate a variable response of eastern African rainfall to low-latitude insolation forcing and high-latitude-driven climate change, likely related to the relative strengths of these forcings through time and a threshold in monsoon sensitivity. We observe little difference in mean rainfall between the early, middle, and late Pleistocene, which suggests that orbitally-driven climate variations likely played a more significant role than gradual change in the relationship between early humans and their environment

Staying well after depression: trial design and protocol

<p>Abstract</p> <p>Background</p> <p>Depression is often a chronic relapsing condition, with relapse rates of 50-80% in those who have been depressed before. This is particularly problematic for those who become suicidal when depressed since habitual recurrence of suicidal thoughts increases likelihood of further acute suicidal episodes. Therefore the question how to prevent relapse is of particular urgency in this group.</p> <p>Methods/Design</p> <p>This trial compares Mindfulness-Based Cognitive Therapy (MBCT), a novel form of treatment combining mindfulness meditation and cognitive therapy for depression, with both Cognitive Psycho-Education (CPE), an equally plausible cognitive treatment but without meditation, and treatment as usual (TAU). It will test whether MBCT reduces the risk of relapse in recurrently depressed patients and the incidence of suicidal symptoms in those with a history of suicidality who do relapse. It recruits participants, screens them by telephone for main inclusion and exclusion criteria and, if they are eligible, invites them to a pre-treatment session to assess eligibility in more detail. This trial allocates eligible participants at random between MBCT and TAU, CPE and TAU, and TAU alone in a ratio of 2:2:1, stratified by presence of suicidal ideation or behaviour and current anti-depressant use. We aim to recruit sufficient participants to allow for retention of 300 following attrition. We deliver both active treatments in groups meeting for two hours every week for eight weeks. We shall estimate effects on rates of relapse and suicidal symptoms over 12 months following treatment and assess clinical status immediately after treatment, and three, six, nine and twelve months thereafter.</p> <p>Discussion</p> <p>This will be the first trial of MBCT to investigate whether MCBT is effective in preventing relapse to depression when compared with a control psychological treatment of equal plausibility; and to explore the use of MBCT for the most severe recurrent depression - that in people who become suicidal when depressed.</p> <p>Trial Registration</p> <p>Current Controlled Trials: ISRCTN97185214.</p

Cancer and psychiatric diagnoses in the year preceding suicide

BACKGROUND: Patients with cancer are known to be at increased risk for suicide but little is known about the interaction between cancer and psychiatric diagnoses, another well-documented risk factor. METHODS: Electronic medical records from nine healthcare systems participating in the Mental Health Research Network were aggregated to form a retrospective case-control study, with ICD-9 codes used to identify diagnoses in the 1 year prior to death by suicide for cases (N = 3330) or matching index date for controls (N = 297,034). Conditional logistic regression was used to assess differences in cancer and psychiatric diagnoses between cases and controls, controlling for sex and age. RESULTS: Among patients without concurrent psychiatric diagnoses, cancer at disease sites with lower average 5-year survival rates were associated with significantly greater relative risk, while cancer disease sites with survival rates of \u3e70% conferred no increased risk. Patients with most psychiatric diagnoses were at higher risk, however, there was no additional risk conferred to these patients by a concurrent cancer diagnosis. CONCLUSION: We found no evidence of a synergistic effect between cancer and psychiatric diagnoses. However, cancer patients with a concurrent psychiatric illness remain at the highest relative risk for suicide, regardless of cancer disease site, due to strong independent associations between psychiatric diagnoses and suicide. For patients without a concurrent psychiatric illness, cancer disease sites associated with worse prognoses appeared to confer greater suicide risk

Iterative Near-Term Ecological Forecasting: Needs, Opportunities, And Challenges

Two foundational questions about sustainability are “How are ecosystems and the services they provide going to change in the future?” and “How do human decisions affect these trajectories?” Answering these questions requires an ability to forecast ecological processes. Unfortunately, most ecological forecasts focus on centennial-scale climate responses, therefore neither meeting the needs of near-term (daily to decadal) environmental decision-making nor allowing comparison of specific, quantitative predictions to new observational data, one of the strongest tests of scientific theory. Near-term forecasts provide the opportunity to iteratively cycle between performing analyses and updating predictions in light of new evidence. This iterative process of gaining feedback, building experience, and correcting models and methods is critical for improving forecasts. Iterative, near-term forecasting will accelerate ecological research, make it more relevant to society, and inform sustainable decision-making under high uncertainty and adaptive management. Here, we identify the immediate scientific and societal needs, opportunities, and challenges for iterative near-term ecological forecasting. Over the past decade, data volume, variety, and accessibility have greatly increased, but challenges remain in interoperability, latency, and uncertainty quantification. Similarly, ecologists have made considerable advances in applying computational, informatic, and statistical methods, but opportunities exist for improving forecast-specific theory, methods, and cyberinfrastructure. Effective forecasting will also require changes in scientific training, culture, and institutions. The need to start forecasting is now; the time for making ecology more predictive is here, and learning by doing is the fastest route to drive the science forward

Inhibiting Inducible Nitric Oxide Synthase in Enteric Glia Restores Electrogenic Ion Transport in Mice With Colitis

BACKGROUND & AIMS: Disturbances in the control of ion transport lead to epithelial barrier dysfunction in patients with colitis. Enteric glia regulate intestinal barrier function and colonic ion transport. However, it is not clear whether enteric glia are involved in the epithelial hypo-responsiveness. We investigated enteric glial regulation of ion transport in mice with trinitrobenzene sulphonic acid- or dextran sodium sulfate-induced colitis and in Il10(−/−) mice. METHODS: Electrically-evoked ion transport was measured in full-thickness segments of colon from CD1 and Il10(−/−) mice with or without colitis in Ussing chambers. Nitric oxide (NO) production was assessed using amperometry. Bacterial translocation was investigated in the liver, spleen and blood of mice. RESULTS: Electrical stimulation of the colon evoked a tetrodotoxin-sensitive chloride secretion. In mice with colitis, ion transport almost completely disappeared. Inhibiting inducible NO synthase (NOS2), but not neuronal NOS (NOS1), partially restored the evoked secretory response. Blocking glial function with fluoroacetate, which is not a NOS2 inhibitor, also partially restored ion transport. Combined NOS2 inhibition and fluoroacetate administration fully restored secretion. Epithelial responsiveness to vasoactive intestinal peptide was increased after enteric glial function was blocked in mice with colitis. In colons of mice without colitis, NO was produced in the myenteric plexus almost completely via NOS1. NO production was increased in mice with colitis, compared to mice without colitis; a substantial proportion of NOS2 was blocked by fluoroacetate administration. Inhibition of enteric glial function in vivo reduced the severity of trinitrobenzene sulphonic acid -induced colitis and associated bacterial translocation. CONCLUSIONS: Increased production of NOS2 in enteric glia contributes to the dysregulation of intestinal ion transport in mice with colitis. Blocking enteric glial function in these mice restores epithelial barrier function and reduces bacterial translocation