Abstract: The ability to tell time, anticipate future events, and produce accurately timed motor behaviors, are among the most fundamental computations the brain performs. Speech and music perception, for example, provide sophisticated examples of temporal processing as they require the ability to parse the order, duration, and the global temporal structure of complex stimuli. Precisely because of the importance of time and timing to brain function, we have proposed that timing on the scale of seconds is a general property of neocortical circuits. I will present experimental and computational studies that suggest that the ability to tell time relies on the inherent dynamics of neural circuits in the form of neural population clocks. To test the hypothesis that neocortical circuits are intrinsically capable of temporal processing we have shown that cortical circuits in a dish can learn temporal patterns and generate timed predictions. Finally, I will present experimental and computational studies suggesting a relationship between timing and working memory, and their potential reliance on the same neural representations.

Abstract: Since the dawn of life, evolution of novel metabolic pathways has enabled new strategies for exploiting environmental resources and manipulating competing and cooperating organisms. Bioinformatic evidence suggests that organisms evolve novel metabolic pathways by patching together existing enzymes with promiscuous side activities into new combinations. However, many questions remain. What promiscuous enzymes were available in the organism in which a new pathway evolved? Why did one pathway emerge rather than other possibilities? Did the first pathway to be discovered “win”, or did subsequent evolution allow a better solution to emerge?

We define “protopathways” as the earliest stage in the evolution of novel pathways. At this stage, promiscuous enzymes are serving new functions as well as their native functions and proper regulation has not emerged. We have developed a model system that allows us to follow the emergence of protopathways. We delete pdxB, a gene required for synthesis of the essential cofactor pyridoxal 5’-phosphate (PLP, aka vit B6) in g-proteobacteria. Complicated population dynamics occurred during laboratory evolution of ∆pdxB E. coli as competing clones rose and fell in abundance. Within 150 generations, a dominant clone (JK1) had evolved a four-step protopathway that bypasses the block in PLP synthesis caused by deletion of pdxB. We have identified the order in which four mutations arose in JK1 and the physiological effect of each. Interestingly, the second mutation created a cheater that was less fit on its own but thrived in the population by scavenging nutrients released from the fragile parental cells. The dominant lineages at the end of the experiment all derived from this cheater strain. We have also evolved ∆pdxB strains of Salmonella enterica, Alliivibrio fischeri and Pseudomonas putida. In some cases, different mutations led to the same novel protopathway. In others, a different protopathway emerged.

Abstract: As genomic datasets grow in size empiricists are faced with the daunting task of making sense of a flood of information. To keep pace with this explosion in data, computational methodologies are being rapidly developed to best utilize genomic sequence data from hundreds to tens of thousands of individuals for the purposes of evolutionary genetic inference. In this seminar I will talk about work done by my group to leverage supervised machine learning techniques for population genetic inference. In particular I will cover recent applications of deep learning on unreduced genotype matrices for a number of population genetic tasks including recombination rate estimation, geographic prediction, and spatial population genetic inference.

Abstract: Adaptations to divert the attacks of visually guided predators have evolved repeatedly in animals. However, few studies have examined how invertebrates have evolved to use ultrasonic hearing against bats. Over the last 12 years, our research team has synergistically conducted behavioral experiments, phylogenetics, and functional genomics to examine how the more than 140,000 moth species evolved to escape bats – their primary predator at night. Over the last 60 million years, moths have evolved ultrasonically sensitive ears and ultrasound-producing organs to combat bat attack. Some moths to have gone a step further and gained the ability to jam bat sonar using tymbals on their thorax or by stridulating their genitalia, allowing them to inhabit new environments. Others generate acoustic diversion with spinning tails to deflect echolocating bat attack. This presentation will include high-speed infrared videography of moths and bats to elucidate the function and evolution of anti-bat strategies. The presentation will also include a discussion on lab research on the impact of human-driven light pollution on moths and bats.

Come join the Spatial Ecology and Paleontology Lab every Friday for Fossil Fridays! 

Become a fossil hunter and help discover how vertebrate communities have changed through time. Experience firsthand what it is like to be a paleontologist, finding and identifying new specimens! 

You will be picking and sorting 3,000 to 30,000-year-old fossil specimens from rock matrix that has been brought back from Natural Trap Cave, WY. These specimens are part of many research projects examining how the community of species living around Natural Trap Cave has changed since the extinction of the cheetahs, lions, dire wolves, mammoths, camels, horses, and other megafauna that used to live in North America. 

You are welcome to participate anytime that is convenient, with no commitment necessary. In fact, you can drop in or leave anytime within the two-hour timeframe. All are welcome, so bring your friends! 

For more information join the mailing list and/or contact Katie Slenker (kslenker3@gatech.edu) or Jenny McGuire (jmcguire@gatech.edu).

​* No T. rex actually helped with the excavations of Natural Trap Cave as their arms would be much too small.

Come join the Spatial Ecology and Paleontology Lab every Friday for Fossil Fridays! 

Become a fossil hunter and help discover how vertebrate communities have changed through time. Experience firsthand what it is like to be a paleontologist, finding and identifying new specimens! 

You will be picking and sorting 3,000 to 30,000-year-old fossil specimens from rock matrix that has been brought back from Natural Trap Cave, WY. These specimens are part of many research projects examining how the community of species living around Natural Trap Cave has changed since the extinction of the cheetahs, lions, dire wolves, mammoths, camels, horses, and other megafauna that used to live in North America. 

You are welcome to participate anytime that is convenient, with no commitment necessary. In fact, you can drop in or leave anytime within the two-hour timeframe. All are welcome, so bring your friends! 

For more information join the mailing list and/or contact Katie Slenker (kslenker3@gatech.edu) or Jenny McGuire (jmcguire@gatech.edu).

​* No T. rex actually helped with the excavations of Natural Trap Cave as their arms would be much too small.

Come join the Spatial Ecology and Paleontology Lab every Friday for Fossil Fridays! 

Become a fossil hunter and help discover how vertebrate communities have changed through time. Experience firsthand what it is like to be a paleontologist, finding and identifying new specimens! 

You will be picking and sorting 3,000 to 30,000-year-old fossil specimens from rock matrix that has been brought back from Natural Trap Cave, WY. These specimens are part of many research projects examining how the community of species living around Natural Trap Cave has changed since the extinction of the cheetahs, lions, dire wolves, mammoths, camels, horses, and other megafauna that used to live in North America. 

You are welcome to participate anytime that is convenient, with no commitment necessary. In fact, you can drop in or leave anytime within the two-hour timeframe. All are welcome, so bring your friends! 

For more information join the mailing list and/or contact Katie Slenker (kslenker3@gatech.edu) or Jenny McGuire (jmcguire@gatech.edu).

​* No T. rex actually helped with the excavations of Natural Trap Cave as their arms would be much too small.

Come join the Spatial Ecology and Paleontology Lab every Friday for Fossil Fridays! 

Become a fossil hunter and help discover how vertebrate communities have changed through time. Experience firsthand what it is like to be a paleontologist, finding and identifying new specimens! 

You will be picking and sorting 3,000 to 30,000-year-old fossil specimens from rock matrix that has been brought back from Natural Trap Cave, WY. These specimens are part of many research projects examining how the community of species living around Natural Trap Cave has changed since the extinction of the cheetahs, lions, dire wolves, mammoths, camels, horses, and other megafauna that used to live in North America. 

You are welcome to participate anytime that is convenient, with no commitment necessary. In fact, you can drop in or leave anytime within the two-hour timeframe. All are welcome, so bring your friends! 

For more information join the mailing list and/or contact Katie Slenker (kslenker3@gatech.edu) or Jenny McGuire (jmcguire@gatech.edu).

​* No T. rex actually helped with the excavations of Natural Trap Cave as their arms would be much too small.

Come join the Spatial Ecology and Paleontology Lab every Friday for Fossil Fridays! 

Become a fossil hunter and help discover how vertebrate communities have changed through time. Experience firsthand what it is like to be a paleontologist, finding and identifying new specimens! 

You will be picking and sorting 3,000 to 30,000-year-old fossil specimens from rock matrix that has been brought back from Natural Trap Cave, WY. These specimens are part of many research projects examining how the community of species living around Natural Trap Cave has changed since the extinction of the cheetahs, lions, dire wolves, mammoths, camels, horses, and other megafauna that used to live in North America. 

You are welcome to participate anytime that is convenient, with no commitment necessary. In fact, you can drop in or leave anytime within the two-hour timeframe. All are welcome, so bring your friends! 

For more information join the mailing list and/or contact Katie Slenker (kslenker3@gatech.edu) or Jenny McGuire (jmcguire@gatech.edu).

​* No T. rex actually helped with the excavations of Natural Trap Cave as their arms would be much too small.