Editorial note. Introduction to the Special Issue "Brain and Behavior: A Neuroscientific / Psychophysiological Approach", in honor and memory of Prof. Jesús Gómez Amor / Nota editorial. Introducción al tema monográfico “Cerebro y conducta: un enfoque neurocientífico/psicofisiológico”, en honor y recuerdo del Prof. Jesús Gómez Amor

Editorial note in which the special theme is presented and a brief comment is made on the articles that compose it.(AU)

Nota editorial en la que se presenta el monográfico y se hace un breve comentario de los artículos que lo componen.(AU)

Autonomic, hormonal, and subjective responses to a modified version of the TSST: a pilot study / Respuesta autónoma, hormonal y subjetiva a una versión modificada del TSST: un estudio piloto

The aim of this research was to study autonomic, hormonal, and subjective responses to a modified version of an extensively employed laboratory stressor, the Trier Social Stress Test (TSST), in a sample of 38 young university students (11 men and 27 women, 11 in the luteal phase and 16 in the follicular phase of the menstrual cycle). Heart rate and Electrodermal Activity were recorded during the entire experimental session. The hormonal response was evaluated by means of salivary cortisol levels, and state anxiety was assessed before and after the task. The speech phase of the TSST elicited the highest heart rate and frequency of non-specific responses, showing significant differences compared to the habituation and recovery phases. However, the cortisol and subjective responses to stress were not statistically significant. Men showed higher frequency of non-specific responses and greater skin conductance levels than both groups of women, as well as higher cortisol concentrations, but only in comparison with women in the luteal phase. Our results provide evidence that this modified version of the TSST elicits a different pattern of psychophysiological responses, including a lack of cortisol response to stress.(AU)

El objetivo de esta investigación fue estudiar las respuestas hormonales, autonómicas y afectivas a una versión modificada de un estresor de laboratorio ampliamente utilizado, el denominado Trier Social Stress Test (TSST), en una muestra de treinta y ocho jóvenes universitarios (11 hombres y 27 mujeres, 11 en la fase lútea y 16 mujeres en la fase folicular del ciclo menstrual). La frecuencia cardíaca y la actividad electrodérmica se registraron durante toda la sesión experimental, la respuesta hormonal se evaluó por medio de las concentraciones de cortisol en saliva y la ansiedad-estado se evaluó antes y después de la tarea. La fase de discurso del TSST provocó la frecuencia cardíaca más elevada y la mayor frecuencia de respuestas inespecíficas, mostrando diferencias significativas con las fases de habituación y recuperación. Sin embargo, la respuesta de cortisol y la respuesta afectiva al estrés no fueron significativas. Los hombres mostraron mayor frecuencia de respuestas inespecíficas y mayor nivel de conductancia de la piel que ambos grupos de mujeres y mayor nivel de cortisol pero sólo en comparación con las mujeres en la fase lútea. Nuestros resultados proporcionan evidencia de que esta versión modificada del TSST provocó un patrón diferente de respuestas psicofisiológicas, incluyendo una falta de respuesta de cortisol al estrés.(AU)

Effects of psychosocial stress on the hormonal and affective response in children with dyslexia.

INTRODUCTION: Research on stress and dyslexia has mainly focused on chronic and contextual stress caused by the school environment. Our goal was to test individual differences in the hypothalamic-pituitary-adrenal (HPA) axis reactivity of dyslexic and non-dyslexic children and the related emotional manifestations associated with exposure to a psychosocial stressor. METHODS: Eighty-one children (11-14 years old; 38 dyslexic) were exposed to the Trier Social Stress Test adapted to children or to a control condition. The salivary cortisol response, anxiety, and mood were measured before and after the stress. RESULTS: Dyslexic children did not show the expected cortisol response, as the highest percentage of children who were non-reactive to stress was found in this group. Cortisol reactivity to stress was related to higher levels of anxiety and lower positive affect in the non-dyslexic children. CONCLUSION: These results suggest a pattern of hypo-activation of the HPA axis to psychosocial stress in children with dyslexia.

Effects of sex and menstrual cycle phase on cardiac response and alpha- amylase levels in psychosocial stress.

The impact of sex and the menstrual cycle phase on the autonomic response to psychosocial stress remains controversial. This study explored autonomic nervous system activity through salivary alpha-amylase, heart rate, and heart rate variability responses to the Trier Social Stress Test (TSST) in healthy young people. The sample was composed of 25 men, 26 women in the luteal phase, and 25 women in the follicular phase, from 18 to 25 years of age. Participants were exposed to the TSST or a control condition. The results indicate that women in their follicular phase showed a blunted alpha-amylase response to stress compared to men and women in the luteal phase. In addition, men showed higher sympatho-vagal activity in the stress condition compared to the two groups of women. These results confirm that sex and the menstrual cycle phase are potential modulators of autonomic nervous system reactivity to psychosocial stress.

Microcystins and cyanophyte extracts inhibit or promote the photosynthesis of fluvial algae. Ecological and management implications.

The ecological influence of cyanotoxins on aquatic biota remains unclear despite the numerous published references on toxicological and sanitary problems related with cyanophyte proliferation. The effects of microcystins and cyanophyte extracts on the photosynthesis of the algae that belong to two taxonomic groups, Rhodophyta and Bacillariophyta, were studied in an attempt to elucidate their role in the intraspecific competence and physiognomy of fluvial communities. The data showed that both cyanobacteria extracts and pure microcystin-LR affected the photosynthetic activity of all the tested organisms, diatoms (Fistulifera pelliculosa, Gomphonema parvulum, Nitzschia frustulum and Stephanodiscus minutulus) and red algae (Chroothece richteriana) at environmentally relevant concentrations. Effects varied with strains and time, and promoted or inhibited photosynthesis. The microcystins and the other compounds present in cyanobacteria extracts may explain the competence effects observed in nature, especially in calcareous environments where they predominate, and after disturbing events like heavy rains or floods, which may destroy cyanophyte mats and release toxic or inhibitory compounds in a seasonal scale pattern.

The influence of coping strategies and behavior on the physiological response to social stress in women: The role of age and menstrual cycle phase.

There is information indicating that the variations induced by the menstrual cycle may influence the capacity of young women to respond to stress. The physiological response to stress changes across the stages of the lifespan; however, in spite of the great increase in life expectancy, the way women react after menopause, a period characterized by a dramatic decline in sex hormones, has not been sufficiently studied. The main objective of the study was to examine the capacity to respond to and recover from an acute social stressor in post-menopausal women compared to young women. The second objective was to investigate the consequences of behavior on the self-regulatory systems. We measured behavior, cortisol, and heart rate during a speaking task in front of a committee in sixty-seven women: 36 post-menopausal and 31 pre-menopausal (follicular group n=14; luteal group n=17). No differences in heart rate reactivity between three groups were found. Post-menopausal women showed less cortisol reactivity to stress; they also displayed a higher percentage of Gestures during the speaking task, reflecting a clearer pattern of active coping compared to the young women. In post-menopausal women, behaviors that reflect active coping strategies were related to better autonomic regulation. By contrast, in pre-menopausal women, cortisol changes seemed to be modulated by passive and reactive behaviors such as Submission and Assertion. These results emphasize the importance of considering age and Hormonal Status in coping processes, including reactivity and recovery from stressful situations.

Autonomic markers associated with generalized social phobia symptoms: heart rate variability and salivary alpha-amylase.

The study of autonomic nervous system changes associated with generalized social phobia (GSP) disorder has increased in recent years, showing contradictory results. The present study aimed to evaluate how young people with GSP reacted before, during, and after exposure to the Trier Stress Social Test (TSST), focusing on their autonomic changes (heart rate variability (HRV) and salivary alpha-amylase (sAA)) compared to a control group (non-GSP). Some psychological variables were also considered. Sex was specifically studied as a possible modulator of autonomic fluctuations and psychological state. Eighty young people were randomly distributed into two counterbalanced situations: stress condition (N = 18 and 21 for GSP and non-GSP, respectively) and control condition (N = 21 and 20 for GSP and non-GSP, respectively), where cardiovascular variables were continuously recorded. Psychological questionnaires about mood and perceived stress were filled out, and five saliva samples were collected to analyze sAA. GSP participants showed higher values on low- and high-frequency ratios (HR domains), compared to non-GSP people, during exposure to the TSST, but no differences were observed after the stressor. Furthermore, the two groups did not differ in sAA. Importantly, positive affect in GSP participants was modulated by sex. The present study suggests that the balance between high- and low-frequency domains of HRV is a key cardiovascular marker reflecting the stress response of GSP people, as well the importance of sex in positive affect when facing a stressful situation.

No effects of psychosocial stress on memory retrieval in non-treated young students with Generalized Social Phobia.

Generalized Social Phobia (GSP) is a common anxiety disorder that produces clear social life disruptions. There is no consensus on the specific processes involved in its development, but the role of the hypothalamic-pituitary-adrenal (HPA) axis has been suggested. This study analyzed the effects of the cortisol response to the Trier Social Stress Test (TSST) on the memory retrieval of pictures with different emotional valences in 45 non-treated young students with GSP and 50 non-anxious (NA) subjects (mean=19.35years, SD=0.18). No differences were found in the cortisol response of GSP and NA subjects to the TSST and control sessions. In addition, psychosocial stress impaired memory retrieval in both the GSP and NA groups, with no differences between them. Regarding the sex factor, no effects were found in the cortisol response to the TSST. However, during the encoding session, GSP men had higher cortisol levels than GSP women and NA subjects. There was also a significant interaction between sex and stress exposure on memory retrieval. Women recognized more unpleasant and neutral pictures than men; however, under stress, the women's advantage disappeared, and the men's performance improved. Sex also interacted with social phobia on positive mood, with GSP women exposed to the TSST showing the lowest positive mood. These results suggest that GSP subjects do not present an HPA axis sensitization to psychosocial stress, and they emphasize the importance of Sex in understanding stress effects on memory.

Acute stress affects free recall and recognition of pictures differently depending on age and sex.

Little is known about age differences in the effects of stress on memory retrieval. Our aim was to perform an in-depth examination of acute psychosocial stress effects on memory retrieval, depending on age and sex. For this purpose, data from 52 older subjects (27 men and 25 women) were reanalyzed along with data from a novel group of 50 young subjects (26 men and 24 women). Participants were exposed to an acute psychosocial stress task (Trier Social Stress Test) or a control task. After the experimental manipulation, the retrieval of positive, negative and neutral pictures learned the previous day was tested. As expected, there was a significant response to the exposure to the stress task, but the older participants had a lower cortisol response to TSST than the younger ones. Stress impaired free recall of emotional (positive and negative) and neutral pictures only in the group of young men. Also in this group, correlation analyses showed a marginally significant association between cortisol and free recall. However, exploratory analyses revealed only a negative relationship between the stress-induced cortisol response and free recall of negative pictures. Moreover, stress impaired recognition memory of positive pictures in all participants, although this effect was not related to the cortisol or alpha-amylase response. These results indicate that both age and sex are critical factors in acute stress effects on specific aspects of long-term memory retrieval of emotional and neutral material. They also point out that more research is needed to better understand their specific role.

Sensitive biosensor based on recombinant PP1α for microcystin detection.

A novel electrochemical microcystin-LR (MC-LR) biosensor based on the inhibition of recombinant protein phosphate type 1 (PP1α) is reported in this work. The use of innovative recombinant enzyme led to investigate new commercially available substrate, electrochemically active after their dephosphorylation by PP1α. Only two of selected substrates, 1-naphylphosphate and phosphoparacetamol, showed a good affinity toward PP1α. Kinetic parameters were performed by classical colorimetric assays and revealed that phosphoparacetamol is an excellent synthetic substrate with a Km value of 1.2 mM. The reported biosensor is constructed by entrapment of the enzyme in Polyvinyl Alcohol (azid unit) on Cobalt-Phtalocyanine (CoPC) modified screen printed electrode. Electrocatalytic mediator demonstrated a significant improvement in the electrochemical detection of dephosphorylated substrate. The standard inhibition curve has provided a limit of detection at 0.93 µg/L and a broad dynamic range from 0.93 to 40.32 µg/L for MC-LR, demonstrating the improved analytical performance.

Acute pre-learning stress and declarative memory: impact of sex, cortisol response and menstrual cycle phase.

This study explores the influence of pre-learning stress on performance on declarative memory tasks in healthy young adults in relation to sex and menstrual cycle phase. The sample was composed of 119 students (32 men and 87 women) from 18 to 25 years of age. The women were tested in different hormonal stages (30 in follicular phase, 34 in luteal phase, and 23 using oral contraceptives). The participants were exposed to the Trier Social Stress Test (TSST) or a control condition. Afterwards, their memory performance was measured using a standardized memory test (Rey's Auditory Verbal Learning Test). In the control condition, all groups of women recalled more words than men, but these differences disappeared in the group exposed to TSST because men's performance on the memory test improved, but only to the level of women. In addition, our data suggest that in women the relationship between cortisol and memory can be modulated by sex hormone levels, since in luteal women a negative relationship was found between memory performance and peak cortisol level. These results confirm that sex differences need to be considered in the relationship between pre-learning stress and memory performance.

Enhancing effects of acute psychosocial stress on priming of non-declarative memory in healthy young adults.

Social stress affects cognitive processes in general, and memory performance in particular. However, the direction of these effects has not been clearly established, as it depends on several factors. Our aim was to determine the impact of the hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) reactivity to psychosocial stress on short-term non-declarative memory and declarative memory performance. Fifty-two young participants (18 men, 34 women) were subjected to the Trier Social Stress Task (TSST) and a control condition in a crossover design. Implicit memory was assessed by a priming test, and explicit memory was assessed by the Rey Auditory Verbal Learning Test (RAVLT). The TSST provoked greater salivary cortisol and salivary alpha-amylase (sAA) responses than the control task. Men had a higher cortisol response to stress than women, but no sex differences were found for sAA release. Stress was associated with an enhancement of priming but did not affect declarative memory. Additionally, the enhancement on the priming test was higher in those whose sAA levels increased more in response to stress (r(48) = 0.339, p = 0.018). Our results confirm an effect of acute stress on priming, and that this effect is related to SNS activity. In addition, they suggest a different relationship between stress biomarkers and the different memory systems.

Salivary alpha-amylase response to acute psychosocial stress: the impact of age.

The impact of stress on health varies across the different stages of human life. Aging is associated with psychobiological changes that could limit our ability to cope with stressors. Therefore, it is crucial to clarify the physiological mechanisms that underlie the stress response and the changes that occur in them as we age. Our aim was to investigate age differences in the salivary alpha amylase (sAA) response to stress, and its relationship with other typical stress biomarkers such as cortisol and heart rate (HR). Sixty-two participants divided into two age groups (younger group: N=31, age range: 18-35 years; older group: N=31, age range: 54-71 years) were exposed to the Trier Social Stress Test and a control condition in a crossover design. No age differences were found in the sAA or HR responses to stress. However, the sAA global output was higher in older than younger adults. Additionally, in the stress condition, the total amount of cortisol released was positively related to the total sAA released, while the HR increase was positively related to the sAA increase. Our results do not support the existence of an attenuated autonomic nervous system response to stress in older adults, but rather a heightened sympathetic tone. Furthermore, we found further evidence of the coordination between the hypothalamus-pituitary-adrenal system and the autonomic nervous system in their response to acute psychosocial stress.

The impact of cortisol reactivity to acute stress on memory: sex differences in middle-aged people.

Stress has been identified as a main factor involved in the cognitive changes that occur during the aging process. This study investigated sex differences in the relationship between the magnitude of the acute stress-induced salivary cortisol response and memory performance among middle-aged people. To this end, 16 men and 16 women (aged 54-72 years) were exposed to the Trier Social Stress Test and a control condition in a crossover design. Afterwards their memory performance was measured using a standardized memory test (Rey's Auditory Verbal Learning Test). Only among women, there was an acute impact of stress on memory performance and a significant relationship between a higher cortisol response to the stressor and poorer memory performance in both the stress and control conditions. Additionally, a poorer memory performance was related to earlier timing of sexual maturation (age at menarche), which was also marginally related to higher cortisol reactivity to stress. These results confirm that sex is a critical factor in the relationship between cortisol and poor memory performance. Furthermore, the findings emphasize a strong link between the individual cortisol response to stress and memory functioning among postmenopausal women.