Marcos Domic

Animals respond to threatening situations by exhibiting a number of defensive behaviors, including avoidance, freezing, and risk assessment. An animal model with an ethological approach offers a deeper insight into the biological mechanisms underlying threat responses. This paper describes a methodology to measure defensive behaviors toward both innate and learned aversive stimuli in rats. Animals were individually exposed to predator odor in an inescapable chamber to elicit a measurable, sustained, defensive state. The experimental design involved placing a rat in a familiar chamber for 10 min followed by exposure to cat odor for another 10 min in the same context. The next day, the rats were re-exposed for 10 min to the same context chamber where cat odor exposure occurred. Sessions were video-recorded and defensive behaviors were assessed on both days. The behavioral test was coupled with reversible functional inactivation and c-Fos immunohistochemistry techniques to determine the role of the interoceptive cortex in threat responses. Rats exposed to cat odor on the first day and re-exposed to the context chamber on the second day displayed higher levels of defensive behaviors, and that cat odor elicited a robust increase in the neural activity of the interoceptive cortex. Moreover, muscimol inactivation of the interoceptive cortex reduced the expression of defensive behaviors in response to cat odor and impaired contextual threat memory. These results show that this behavioral assay is a useful tool for studying neural mechanisms of defensive behaviors and may offer insight into mechanisms that mediate fear in humans and its related disorders.

Fibromyalgia (FMS) is a chronic condition that encompasses widespread pain associated with cognitive impairment and significant emotional distress related to functional disability that affects mainly women. However, the mechanisms underlying the origin of the cognitive impairments and how the current COVID-19 pandemic impacts remain elusive. This study aimed to determine whether there is an association between cognitive performance in executive functions, physical pain, and psychological distress caused by the pandemic in a group of Chilean women with FMS using a novel online protocol of neuropsychological evaluation. We found that women with FMS present cognitive impairment predominantly explained by pain and anxiety symptoms, which are associated with the difficulties experienced from the COVID-19 pandemic. These results point out the importance of considering a broader perspective for treatment, including anxiety symptoms and the psychological distress caused by the pandemic as a therapeutic target for cognitive impairments.

There is abundant evidence about the negative impact of discrimination on well-being, but less research on factors that can reduce this negative effect, mainly focused on North American samples and with incipient development on South-South migration. The objective of this research was to analyze the effect of ethnic identity on the relationship between the experience of racial and ethnic discrimination and psychological well-being in Colombian immigrants living in Chile. A total of 962 immigrants over the age of 18 from three cities in Chile participated. Of these, 50.7% were women. The average age was 35 years (SD = 10.23). Participants were evaluated using Ryff's Psychological Well-Being Scales, Phinney's adapted version of the Multigroup Ethnic Identity Scale, and Krieger's Discrimination Experience Scale. After the analysis of the measurement models, a mediation model was analyzed using structural equations. The results provide evidence that ethnic and racial discrimination have negative effects on psychological well-being, with the effect of racial discrimination being greater. Likewise, ethnic identity has positive effects on psychological well-being and partially and completely mediates the effects of ethnic and racial discrimination on psychological well-being. The full effect of discrimination on psychological well-being, mediated by ethnic identity, is exercised only by racial discrimination and not by ethnic discrimination.

Cognitive planning, the ability to develop a sequenced plan to achieve a goal, plays a crucial role in human goal-directed behavior. However, the specific role of frontal structures in planning is unclear. We used a novel and ecological task, that allowed us to separate the planning period from the execution period. The spatio-temporal dynamics of EEG recordings showed that planning induced a progressive and sustained increase of frontal-midline theta activity (FMθ) over time. Source analyses indicated that this activity was generated within the prefrontal cortex. Theta activity from the right mid-Cingulate Cortex (MCC) and the left Anterior Cingulate Cortex (ACC) were correlated with an increase in the time needed for elaborating plans. On the other hand, left Frontopolar cortex (FP) theta activity exhibited a negative correlation with the time required for executing a plan. Since reaction times of planning execution correlated with correct responses, left FP theta activity might be associated with efficiency and accuracy in making a plan. Associations between theta activity from the right MCC and the left ACC with reaction times of the planning period may reflect high cognitive demand of the task, due to the engagement of attentional control and conflict monitoring implementation. In turn, the specific association between left FP theta activity and planning performance may reflect the participation of this brain region in successfully self-generated plans.

Neural correlates of cognitive planning are not understood well at present. Behavioral paradigms targeting this function are a current challenge in cognitive neuroscience. We recorded EEG activity while subjects were performing a novel behavioral paradigm that evaluates cognitive planning function. Participants showed longer reaction times and decreased accuracy during the planning condition compared to the control condition, suggesting that the planning condition is more time consuming, therefore reflecting higher cognitive demand. Moreover, cognitive planning induced a frontal midline theta (FMθ) frequency band originating in prefrontal cortex (PFC) as shown in previous cognitive control studies. When subjects began planning, there was a progressive and sustained increase in FMθ starting after 500 milliseconds (ms) of planning. Hence, we characterized for first time, both spatial and temporal FMθ dynamics of cognitive planning as a marker of cognitive control function.

To assess, among Chilean students, the reliability and validity of three scales that measure attention deficit hyperactivity disorder (ADHD): the ADHD Rating Scale-IV (ADHD-IV); the scale for evaluating attention deficit disorder with hyperactivity (EDAH); and Spain's version of the ADHD Rating Scale-IV (Spa-ADHD-IV). A study of the instruments was conducted with the tutors (n = 612) and teachers (n = 82) of a controlled sample of 640 children 6-11 years of age, who were students attending public schools (n = 228, 35.6% of total), subsidized schools (n = 200, 31.3%), or private schools (n = 212, 33.1%) in Antofagasta, Chile. The convergent validity of the ADHD rating instruments was determined using Stroop and Wechsler tests. All three scales studied had satisfactory levels of internal consistency (Cronbach's alpha of 0.88-0.97 for the scales; 0.76-0.97 for the items) and a factor structure that was theoretically-aligned for most of the assessment areas, although only the Spa-ADHD-IV with tutors and teachers and the ADHD-IV with teachers had comparative and relative fit indices greater than 0.90. Significant differences were found by age, gender, and type of evaluator (tutor or teacher). The ADHD-IV and Spa-ADHD-IV met all reliability and validity criteria; so both may be applied for screening and diagnosis in the Chilean population. The Spa-ADHD-IV scale offers the best psychometric properties based on its reliability and validity.

Objective: To evaluate the prevalence of Attention Deficit/Hyperactivity Disorder (ADHD) in the city of Antofagasta. Patients and Methods: Teachers and parents of 640 children (290 boys and 350 girls) between 6 and 11 years, from public, subsidized and private schools were evaluated through the Attention Deficit Hyperactivity Disorder Rating Scale-IV [ADHD-RS IV]. Results: Utilizing the ADHD Scale independently, the prevalence ranged between 5% and 15% depending on the informant. This number decreased to 2% when the criteria were required both at home and school environments. Conclusion: In our population the prevalence of ADHD is highest in boys 6 to 8 years of age, being the combined disorder the most common subtype found in this group.

Objective: To evaluate the prevalence of Attention Deficit/Hyperactivity Disorder (ADHD) in the city of Antofagasta. Patients and Methods: Teachers and parents of 640 children (290 boys and 350 girls) between 6 and 11 years, from public, subsidized and private schools were evaluated through the Attention Deficit Hyperactivity Disorder Rating Scale-IV [ADHD-RS IV]. Results: Utilizing the ADHD Scale independently, the prevalence ranged between 5% and 15% depending on the informant. This number decreased to 2% when the criteria were required both at home and school environments. Conclusion: In our population the prevalence of ADHD is highest in boys 6 to 8 years of age, being the combined disorder the most common subtype found in this group.