Tag: Poster 73

The Effects of Red and Green Colored Word Stimuli on Neural Processing and Behavior during an Emotional Stroop Task: An Event-Related Potential Investigation

Presenter: Katia Krane

Faculty Mentor: Don Tucker, Anita Christie

Presentation Type: Poster 73

Primary Research Area: Science

Major: Human Physiology, Psychology

Western associations of colors, especially of red and green, influence how individuals consciously perceive the meanings of these colors. However, very little research has investigated the underlying neural processes of localized colors presented as meaningful stimuli, like words, and the possible effects these colors have on behavior. The aim of this study was to investigate initial neural responses to red and green colored word stimuli and the effects of these colors on behavior, including working memory and response time. Using dense-array EEG, event-related potentials (ERPs) were recorded following presentation of word stimuli in red and green ink. ERPs represent measurements of post-synaptic potentials following a response evoking stimulus, in this case red and green colored words, to show real time neural processing of stimuli immediately after presentation. Additionally, memory recall and average response times for each color category were recorded. Participants recalled more red colored words than green, however, did not show significant differences in average response times during the emotional Stroop task, indicating that color may impact working memory but not response performance during the Stroop task. ERP waveform amplitude differences between color categories in components known to be involved in visual processing and discrimination, such as the C1, P1 and N1, suggest that differences in color perception occur quickly post stimulus presentation. These results suggest a bottom-up cognitive mechanism of color perception that may influence behaviors, such as working memory. Associations of the colors red and green may not simply be arbitrary, but linked to underlying differences in neural processing which may imply biases in previous research in which an emotional Stroop task was used to investigate behavioral and neural responses.

SMC-5/6 Facilitates Efficient DSB Repair During Meiosis in C. elegans

Presenter(s): Cordell Clark − Biology

Faculty Mentor(s): Diana Libuda, Erik Toraason

Poster 73

Oral Session 3M

Research Area: Biological Science

Funding: OURS Program Summer 2017, Dr. Diana Libuda’s laboratory is funded in part by an NICHD grant

Sexually reproducing organisms depend upon meiosis to form haploid sex cells necessary for reproduction. Despite the inherent risks of DNA damage to genome integrity, meiotic cells intentionally induce double strand DNA breaks (DSBs) throughout the genome. A specific and limited number of DSBs must be repaired as crossovers with the homologous chromosome to promote proper chromosome segregation. DSBs are induced in excess of the permitted number of crossovers. DSBs not repaired as crossovers must be repaired to maintain genomic integrity. In the Libuda lab, we have designed an assay to determine the repair outcome of a single induced DSB. We have demonstrated that in addition to the homologous chromosome, the sister chromatid is used as a repair template during DSB repair in C. elegans meiosis. My research aims to uncover the mechanisms that facilitate intersister repair, which are currently unknown. Experiments in multiple species have demonstrated that SUMOylation is required for crossover formation. Our preliminary immunofluorescence experiments in SUMO deficient mutants reveal SUMOylation is required for DSB repair in C. elegans oocytes. Prior research has hypothesized that the SMC5/6 complex, which contains a SUMO ligase subunit (NSE-2), facilitates intersister recombination. Using our intersister repair assay, I have demonstrated that the SMC5/6 complex is required for efficient intersister repair and intersister crossovers. My ongoing experiments are directly testing whether the SMC5/6 complex promotes intersister recombination via the NSE-2 SUMO ligase subunit. Overall, our studies are defining the mechanisms that facilitate intersister recombination to ensure genome integrity during sperm and egg development.

Life History Responses to Variation in Bacterial Food Sources in the Nematode Caenorhabditis elegans

Presenter(s): Alexander Smith

Faculty Mentor(s): Patrick Phillips & Stephen Banse

Poster 73

Session: Sciences

Diet is directly tied to the life history traits of an organism. Life history traits, such as development, reproductive capability, and lifespan, respond to changes in diet. The nematode Caenorhabditis elegans can serve as a model to demonstrate the effect of various bacterial diets on development and fecundity. Using various available natural bacteria isolates, we screened for bacterial diets that produce observable effects on the health and development of nematodes. Two bacteria species, Comamonas aquatica and Comamonas testosteroni, were observed to produce accelerated development in the growing nematodes relative to the standard laboratory diet of E. coli OP50. This prompted investigation into whether a tradeoff exists between life history traits, or whether this food source is simply a better food. We measured the number of offspring produced by organisms given a diet of Comamonas aquatica or Comamonas testosteroni and found that it is less with the number normally observed in nematodes given a diet of E. coli OP50. This demonstrates a tradeoff that is also well understood in temperature. When temperature is increase, nematode development is accelerated, and total offspring count is reduced. We found that when fed a diet of Comamonas aquatica or Comamonas testosteroni that the pattern of change relative to temperature is not consistent with nematodes on a diet of E. coli OP50. This work shows that this change in diet produces a tradeoff between development time and total offspring count, and that interactions with abiotic factors do not alleviate the tradeoff completely. Future research could show the specific nutrient composition differences in bacteria species that are responsible for the accelerated development and reduced offspring count.