Acute stress enhances general-knowledge semantic memory

The invisibility of the cognitive cost of military police work

OBJECTIVE

To assess the cognitive cost of work for military police officers in the state of Rio de Janeiro.

METHOD

This is a cross-sectional study with a quantitative approach, carried out with 446 military police officers, of both sexes, distributed between non-commissioned officers and officers, in the 7th, 15th, 20th, 24th and 41st Military Police Battalions. An instrument was used to depict sociodemographic, work, lifestyle and health conditions and a scale for assessing the human cost of work, which analyses the demands of the job through physical, cognitive and affective costs. The data was organized, processed and analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 13.1.

RESULTS

The cognitive cost had the highest means, with severe results (μ = 3.86; SD = 0.86), representing greater demands in relation to the human cost of work among military police officers in the state of Rio de Janeiro and significant associations in relation to obesity, cognitive alterations in attention and memory, age and hours of sleep.

CONCLUSION

In assessing the human cost of work, the cognitive cost was the most demanding in the work context of the military police officers surveyed, presenting a serious risk of illness.

Neuroendocrine response to a psychosocial stress test is not related to schizotypy but cortisol elevation predicts inflexibility of semantic memory retrieval

An altered stress response can contribute to the transition from preclinical psychotic symptoms to the clinical manifestation of schizophrenia and other psychotic disorders. The present study was aimed at testing the hypotheses that (i) the autonomic and neuroendocrine responses under psychosocial stress are dysregulated in individuals with high psychosis proneness (schizotypy); (ii) the magnitude of post-stress autonomic activation and cortisol release predicts alterations in semantic memory retrieval. The study was performed in 73 healthy individuals of both sexes with either high or low schizotypal traits preselected out of 609 individuals using the Schizotypal Personality Questionnaire. A psychosocial stress procedure based on public speech was used as a stress model. We found that individuals with high schizotypy engaged in less adaptive emotional stress-coping strategies than low schizotypy individuals. Yet, the neuroendocrine, immune, and sympathetic activation in response to the stress test was not different between the groups. Irrespective of the exposure to the stressor, individuals with high schizotypy were less fluent when retrieving associations from semantic memory. In addition, we demonstrated that acute psychosocial stress reduced the flexibility of semantic memory retrieval. The post-stress mental inflexibility was reliably predicted by the concomitant elevation of cortisol concentrations in saliva. The present study thus brings novel evidence indicating that the acute psychosocial challenge impairs retrieval flexibility in the semantic domain, which may be due to neuroendocrine activation.

The Forward Testing Effect Is Resistant to Acute Psychosocial Retrieval Stress

The forward testing effect refers to the finding that testing of previously studied information improves memory for subsequently studied newer information. Recent research showed that the effect is immune to acute psychosocial encoding/retrieval stress, i.e., stress that is induced before initial encoding. The present study investigated whether the forward testing effect is also robust to acute psychosocial retrieval stress, i.e., stress that is induced after encoding but before retrieval of the critical item list. Participants (N = 128) studied three lists of words in anticipation of a final cumulative recall test. Participants were tested immediately on Lists 1 and 2 (testing condition) or restudied the two lists after initial study (restudy condition). After study of the critical List 3, psychosocial stress was induced in half of the participants (stress group), whereas no stress was induced in the other half (control group). The Trier Social Stress Test for Groups (TSST-G) was used for stress induction. Salivary cortisol, alpha amylase, and subjective stress were repeatedly measured. The results of the criterion test showed a generally detrimental effect of psychosocial retrieval stress on List 3 recall. Importantly, the forward testing effect was unaffected by retrieval stress. The findings are discussed with respect to current theories of the forward testing effect.

DASentimental: Detecting Depression, Anxiety, and Stress in Texts via Emotional Recall, Cognitive Networks, and Machine Learning

Most current affect scales and sentiment analysis on written text focus on quantifying valence/sentiment, the primary dimension of emotion. Distinguishing broader, more complex negative emotions of similar valence is key to evaluating mental health. We propose a semi-supervised machine learning model, DASentimental, to extract depression, anxiety, and stress from written text. We trained DASentimental to identify how N = 200 sequences of recalled emotional words correlate with recallers’ depression, anxiety, and stress from the Depression Anxiety Stress Scale (DASS-21). Using cognitive network science, we modeled every recall list as a bag-of-words (BOW) vector and as a walk over a network representation of semantic memory—in this case, free associations. This weights BOW entries according to their centrality (degree) in semantic memory and informs recalls using semantic network distances, thus embedding recalls in a cognitive representation. This embedding translated into state-of-the-art, cross-validated predictions for depression (R = 0.7), anxiety (R = 0.44), and stress (R = 0.52), equivalent to previous results employing additional human data. Powered by a multilayer perceptron neural network, DASentimental opens the door to probing the semantic organizations of emotional distress. We found that semantic distances between recalls (i.e., walk coverage), was key for estimating depression levels but redundant for anxiety and stress levels. Semantic distances from “fear” boosted anxiety predictions but were redundant when the “sad–happy” dyad was considered. We applied DASentimental to a clinical dataset of 142 suicide notes and found that the predicted depression and anxiety levels (high/low) corresponded to differences in valence and arousal as expected from a circumplex model of affect. We discuss key directions for future research enabled by artificial intelligence detecting stress, anxiety, and depression in texts.

Efeito do estresse crônico na memória espacial de curto e longo prazo em ratos Wistar

Objetivo: Investigar a relação entre o estresse crônico e a memória espacial em ratos. Metodologia:Utilizaram-se 20 ratos, machos, com 45 dias de vida, linhagem Wistar, divididos em 2 grupos: Estresse Choque (n = 10), onde foram alocados em uma caixa onde receberam um choque elétrico nas patas traseiras de 0,5 mA, por 2 s, a cada 30 s, por 5 min/dia, por 49 dias consecutivos; e Controle (n = 10), alocados na mesma caixa, porém sem receber estímulo, por 5 min, durante 49 dias. Posteriormente, iniciaram-se os procedimentos comportamentais, que consistiram na Habituação na Arena, Teste de Campo Aberto, Treino de Reconhecimento de Objetos, Teste de Memória de Curto Prazo (TMCP) e Teste de Memória de Longo Prazo (TMLP). Foram obtidas as taxas de duração de preferência exploratória. Os dados foram apresentados como média ± EPM. Resultados: No TMCP, o grupo Estresse Choque apresentou um aumento significativo da taxa de exploração (75,75 ± 4,77% vs 58,49 ± 4,83%; p = 0,023), demonstrando um efeito positivo do estresse crônico sobre a memória de curto prazo. No TMCP, não houve diferença significativa do grupo Estresse Choque (55,23 ± 8,33%) em relação ao Controle (71,61 ± 4,76%; p = 0,146). Conclusão: o estresse crônico revelou efeitos positivos sobre a memória de curto prazo no Teste de Reconhecimento de Objetos, quando comparado ao grupo de controle, porém não obteve efeitos significativos sobre a memória de longo prazo.