Optogenetic Control of ROS Production in C. elegans

Alicia Wei, Keith Nehrke and Andrew Wojtovich 

Reactive Oxygen Species (ROS) can be detrimental or may lead to beneficial adaptive responses. The factors that distinguish between these outcomes are not readily determined using existing techniques. Here, we have developed a novel C. elegans model to study the effects of ROS in a physiologic context using a combination of CRISPR/Cas9 gene editing and optogenetics. Mitochondria are a main source of ROS and are central to cell death and adaptation to stress. We used cutting edge genetic techniques to fuse components of the mitochondrial respiratory chain to proteins that can produce ROS in response to light. MiniSOG produces singlet oxygen, which has the singular capacity to illicit damage, while SuperNova creates superoxide, which we predict may be beneficial in limited amounts. We fused miniSOG to complex II of the mitochondrial respiratory chain in C. elegans. The strain exhibited light-sensitive loss of complex II activity and the worms exhibited adverse reactions to light under conditions of mild stress such as, paraquat, an ROS generator or FCCP, a protonophore. In contrast, the strain expressing the SuperNova fusion had no adverse reaction to light and the conditions of mild stress when coupled with light. Future experiments will be necessary to determine whether light is in fact beneficial in this strain, as we hypothesize. With these constructs, we will be able to study the complex II of the mitochondrial respiratory chain ROS microdomains.

Development of a Sciatic Nerve Schawannoma Model for Surgical Stimulation

Shivali Mukerji, Jonathan Stone and G. Edward Vates

Neurosurgery is a field that requires extreme precision and skill and just like many other medical fields, is currently trying to find solutions to undertrained residents. Surgical education relies on training in the operating room and combined with long working hours, exhaustion this can threaten patient safety, increase operative times, and produce an entire generation of under-trained residents. The aim of this research project is to develop a learning tool that is inexpensive and yet effective in it’s use. Using 3D printed molds and polymer hydrogels, we aim to create an anatomically accurate representation of a sciatic nerve schwannoma extraction surgery. A schwannoma is a benign nerve tumor made of Schwann cells that tends to push the nerve in the affected area aside and if not removed in a timely manner, can cause debilitating pain. Using Poly Vinyl Alcohol (PVA) hydrogels and imaging from patients, layers of the thigh and the various components such as the nerve sheath along with the tumor are created. To replicate the functioning of a nerve, conductive yarn material is integrated into the nerve sheath to replicate nerve activity on stimulation and damage. PVA is selectively cross linked to mimic different tissue structures and capillaries containing blood are added to the dermis to mimic bleeding. This complete model includes all the components of a schwannoma removal surgery from delicate dissection of anatomical planes, identification of proximal and distal nerve ends, subcapsular dissection of the tumor, and multi-layer closure. The objective of this model is two fold- 1) to be an effective learning tool for residents entering the field thereby giving way to future models of more common surgeries and improving confidence amongst residents. T 2) The model provides residents the opportunity to become familiar with an otherwise rare disease.

Center-Embedded Sequence Learning In Children And Non-Human Primates

Abigail Haslinger, Stephen Ferrigno, Steven T. Piantadosi, and Jessica F. Cantlon

Recursion is a computational method that embeds elements inside one another, allowing for long-range relations in a sequence. It is important for a wide variety of human skills, including language, counting, and motor control. To date there has been no conclusive evidence that non-human animals can use center-embedded recursion, the type of recursion necessary for language acquisition. This has led some researchers to hypothesize that it is a uniquely human skill and possibly the limiting factor of human language ability. Here we investigate whether monkeys (rhesus macaques) and children (age 3-5 yrs.) can learn to apply center-embedded recursion in a sequencing task. Subjects were given a task in which they had to touch sets of pictures of brackets in recursive orders, e.g. [ < > ]. We then tested whether subjects could transfer this center-embedded strategy to novel stimuli. We found that children naturally use center-embedded recursion to order novel lists. This suggests that mastery of this task, and thus mastery of a component of human grammar, comes easily to children and develops very early in childhood. Although monkeys did not use center-embedded recursion at first, with additional training, they were capable of learning to use a center-embedded strategy and transfer this skill to novel stimuli. This suggests that center-embedded recursion is not a uniquely human ability and is therefore not likely the limiting factor of language.

No Natural Gender Differences in Children’s Earliest Quantitative Abilities

Kelsey Csumitta and Jessica Cantlon

Despite advances in gender equality within our society, men continue to be overrepresented in math-related careers. If there are “natural” differences in math ability between young boys and girls, these differences may impact later academic and career choices. Although some research has found that boys outperform girls on tests of math achievement in school, cultural influences may be contributing to these differences. Here we examined children’s quantitative processing abilities during early childhood prior to and during the first few years of formal school to provide data on whether and how early gender differences emerge in childhood. Over 400 children between 2 and 7 years were tested across two testing sites. First, we compared the performance of boys and girls on core numerosity perception during infancy and childhood and found that boys and girls performed similarly. Next, we compared boys and girls on verbal counting and knowledge of number word meanings during preschool. Boys and girls demonstrated similar levels of knowledge of number word meanings, but boys showed a slight advantage on culturally-learned memorization. Finally, we compared boys and girls on school-based tests of math achievement during the first few years of formal schooling. Boys and girls performed equally on mathematical concepts that draw on untrained, acquired knowledge, but boys performed slightly better on questions that rely on concepts that are formally taught in school. None of the differences between boys and girls approached one standard deviation. Overall the data show no intrinsic early childhood gender differences in quantitative reasoning, but some negligible gender differences in quantitative concepts that are culturally trained. This suggests that cultural influences may account for the gender discrepancy seen in math-related careers.