an-inescapable-cat-odor-exposure-protocol-for-studying-innate

An Inescapable Cat Odor Exposure Protocol for Studying Innate and Contextual Threat Conditioning in Rats

Animals respond to threatening situations by exhibiting a number of defensive behaviors, including avoidance, freezing, and risk assessment. An animal ...

Universidad del desarrollo

Poly(amidoamine) dendrimers are the most recognized class of dendrimer. Amino-terminated (PAMAM-NH2) and hydroxyl-terminated (PAMAM-OH) dendrimers of generation 4 are widely used, since they are commercially available. Both have different properties, mainly based on their different overall charges at physiological pH. Currently, an important function of dendrimers as carriers of short single-stranded DNA has been applied. These molecules, known as antisense oligonucleotides (asODNs), are able to inhibit the expression of a target mRNA. Whereas PAMAM-NH2 dendrimers have shown to be able to transfect plasmid DNA, PAMAM-OH dendrimers have not shown the same successful results. However, little is known about their interaction with shorter and more flexible molecules such as asODNs. Due to several initiatives, the use of these neutral dendrimers as a scaffold to introduce other functional groups has been proposed. Because of its low cytotoxicity, it is relevant to understand the molecular phenomena involving these types of dendrimers. In this work, we studied the behavior of an antisense oligonucleotide in presence of both types of dendrimers using molecular dynamics simulations, in order to elucidate if they are able to form stable complexes. In this manner, we demonstrated at atomic level that PAMAM-NH2, unlike PAMAM-OH, could form a well-compacted complex with asODN, albeit PAMAM-OH can also establish stable interactions with the oligonucleotide. The biological activity of asODN in complex with PAMAM-NH2 dendrimer was also shown. Finally, we revealed that in contact with PAMAM-OH, asODN remains outside the cells as TIRF microscopy results showed, due to its poor interaction with this dendrimer and cell membranes. 

Effect of Terminal Groups of Dendrimers in the Complexation with Antisense Oligonucleotides and Cell Uptake.

The present study is a comparative case study as part of research on the psychotherapeutic process. This research describes the perception of subjective time in two psychotherapeutic processes, one successful and one unsuccessful.

Psychotherapy and psychological time: a case study.

This study aimed to test the impact of play on the development of executive functions (EFs) in preschoolers. Thirty-two games were designed to be collectively played in groups by 70 children, in their regular classes. The games were specifically designed to promote the development of the three components of EFs: inhibition (behavioral or cognitive), working memory, and cognitive flexibility. The games focused on each function were of three types: playground games, expression games, and classroom games. Sixty 45 min play sessions were held on consecutive days for 3 months, always in the first period. The sessions were guided by two members of the research team, assisted by the four teachers of the participating classes. The intervention was carried out in two highly socially vulnerable schools in the city of Santiago de Chile. Four classes were studied in total: two experimental groups and two controls. The classes were selected using a questionnaire on teacher-student interaction quality and an age homogeneity criterion. EFs were evaluated using the Hearts and Flowers task at three points: before the intervention (T1), immediately after the end of the intervention (T2), and 8 months after the end of the intervention (T3). The results show a significant difference in the growth of EFs by comparing the experimental and control groups ( = 0.04) between T1 and T3. They also reveal a strong correlation between EFs measures at T1 and mathematics performance at T3. These results are discussed within the context of the guidelines proposed by Diamond and Ling (2016) and Barnett (2011) regarding what an EFs promotion program needs to be considered effective and high quality. The program presented in this study meets most of the requisites mentioned by the authors, which proves that following these guidelines guarantees a high probability of success.

Executive Functions Can Be Improved in Preschoolers Through Systematic Playing in Educational Settings: Evidence From a Longitudinal Study.

The insular cortex (IC), among other brain regions, becomes active when humans experience fear or anxiety. However, few experimental studies in rats have implicated the IC in threat responses. We have recently reported that inactivation of the primary interoceptive cortex (pIC) during pre-training, or the intra-pIC blockade of protein synthesis immediately after training, impaired the consolidation of auditory fear conditioning. The present study was designed to investigate the role of the pIC in innate and learned defensive responses to predator odor. Freezing behavior was elicited by single or repetitive exposures to a collar that had been worn by a domestic cat. Sessions were video-recorded and later scored by video observation. We found that muscimol inactivation of the pIC reduced the expression of freezing reaction in response to a single or repeated exposure to cat odor. We also found that pIC inactivation with muscimol impaired conditioning of fear to the context in which rats were exposed to cat odor. Furthermore, neosaxitoxin inactivation of the pIC resulted in a prolonged and robust reduction in freezing response in subsequent re-exposures to cat odor. In addition, freezing behavior significantly correlated with the neural activity of the IC. The present results suggest that the IC is involved in the expression of both innate and learned fear responses to predator odor.

Article	Year
Effect of Terminal Groups of Dendrimers in the Complexation with Antisense Oligonucleotides and Cell Uptake. Nanoscale research letters\| PubMed ID: 26847692	2016
Psychotherapy and psychological time: a case study. Rivista di psichiatria\| PubMed ID: 28692072	2017
Executive Functions Can Be Improved in Preschoolers Through Systematic Playing in Educational Settings: Evidence From a Longitudinal Study. Frontiers in psychology\| PubMed ID: 31551874	2019
Interoceptive Insular Cortex Mediates Both Innate Fear and Contextual Threat Conditioning to Predator Odor. Frontiers in behavioral neuroscience\| PubMed ID: 31998093	2019

Francisco Ceric

Biography

JoVE Journal Publications

Other Publications