Differential mechanisms underlie trace and delay conditioning in Drosophila.

Two forms of associative learning-delay conditioning and trace conditioning-have been widely investigated in humans and higher-order mammals. In delay conditioning, an unconditioned stimulus (for example, an electric shock) is introduced in the final moments of a conditioned stimulus (for example, a tone), with both ending at the same time. In trace conditioning, a 'trace' interval separates the conditioned stimulus and the unconditioned stimulus.

Valence opponency in peripheral olfactory processing.

A hallmark of complex sensory systems is the organization of neurons into functionally meaningful maps, which allow for comparison and contrast of parallel inputs via lateral inhibition. However, it is unclear whether such a map exists in olfaction. Here, we address this question by determining the organizing principle underlying the stereotyped pairing of olfactory receptor neurons (ORNs) in sensory hairs, wherein compartmentalized neurons inhibit each other via ephaptic coupling.

Learning about quantitative genetics from Marla Sokolowski.

Marla Sokolowski is a true pioneer in behavioral genetics, having made the first molecular delineation of a naturally occurring behavioral polymorphism in her work on the foraging locus in . The gene was subsequently found to be responsible for behavioral variants and types in many other species, both invertebrate and mammal (human). The path to get there is a paradigmatic example of how to use the power of genetic analysis, including some rather esoteric techniques, to zero in on a gene and delineate its molecular identity and its pleiotropic roles.

Anti-instinctive Learning Behavior Revealed by Locomotion-Triggered Mild Heat Stress in .

Anti-instinctive learning, an ability to modify an animal's innate behaviors in ways that go against one's innate tendency, can confer great evolutionary advantages to animals and enable them to better adapt to the changing environment. Yet, our understanding of anti-instinctive learning and its underlying mechanisms is still limited. In this work, we describe a new anti-instinctive learning behavior of fruit flies.

Imaging brain activity during complex social behaviors in Drosophila with Flyception2.

Optical in vivo recordings from freely walking Drosophila are currently possible only for limited behaviors. Here, we expand the range of accessible behaviors with a retroreflective marker-based tracking and ratiometric brain imaging system, permitting brain activity imaging even in copulating male flies. We discover that P1 neurons, active during courtship, are inactive during copulation, whereas GABAergic mAL neurons remain active during copulation, suggesting a countervailing role of mAL in opposing P1 activity during mating.

Fast near-whole-brain imaging in adult Drosophila during responses to stimuli and behavior.

Whole-brain recordings give us a global perspective of the brain in action. In this study, we describe a method using light field microscopy to record near-whole brain calcium and voltage activity at high speed in behaving adult flies. We first obtained global activity maps for various stimuli and behaviors.

The genome of the jellyfish Aurelia and the evolution of animal complexity.

We present the genome of the moon jellyfish Aurelia, a genome from a cnidarian with a medusa life stage. Our analyses suggest that gene gain and loss in Aurelia is comparable to what has been found in its morphologically simpler relatives-the anthozoan corals and sea anemones. RNA sequencing analysis does not support the hypothesis that taxonomically restricted (orphan) genes play an oversized role in the development of the medusa stage.

Deep(er) Learning.

Animals successfully thrive in noisy environments with finite resources. The necessity to function with resource constraints has led evolution to design animal brains (and bodies) to be optimal in their use of computational power while being adaptable to their environmental niche. A key process undergirding this ability to adapt is the process of learning.

Flyception: imaging brain activity in freely walking fruit flies.

Genetically encoded calcium sensors have enabled monitoring of neural activity in vivo using optical imaging techniques. Linking neural activity to complex behavior remains challenging, however, as most imaging systems require tethering the animal, which can impact the animal's behavioral repertoire. Here, we report a method for monitoring the brain activity of untethered, freely walking Drosophila melanogaster during sensorially and socially evoked behaviors to facilitate the study of neural mechanisms that underlie naturalistic behaviors.

A National Network of Neurotechnology Centers for the BRAIN Initiative.

We propose the creation of a national network of neurotechnology centers to enhance and accelerate the BRAIN Initiative and optimally leverage the effort and creativity of individual laboratories involved in it. As "brain observatories," these centers could provide the critical interdisciplinary environment both for realizing ambitious and complex technologies and for providing individual investigators with access to them.

Giving Time Purpose: The Synechococcus elongatus Clock in a Broader Network Context.

Early research on the cyanobacterial clock focused on characterizing the genes needed to keep, entrain, and convey time within the cell. As the scope of assays used in molecular genetics has expanded to capture systems-level properties (e.g.

Connectomics-based analysis of information flow in the Drosophila brain.

Understanding the overall patterns of information flow within the brain has become a major goal of neuroscience. In the current study, we produced a first draft of the Drosophila connectome at the mesoscopic scale, reconstructed from 12,995 images of neuron projections collected in FlyCircuit (version 1.1).

High-throughput and quantitative approaches for measuring circadian rhythms in cyanobacteria using bioluminescence.

The temporal measurement of a bioluminescent reporter has proven to be one of the most powerful tools for characterizing circadian rhythms in the cyanobacterium Synechococcus elongatus. Primarily, two approaches have been used to automate this process: (1) detection of cell culture bioluminescence in 96-well plates by a photomultiplier tube-based plate-cycling luminometer (TopCount Microplate Scintillation and Luminescence Counter, Perkin Elmer) and (2) detection of individual colony bioluminescence by iteratively rotating a Petri dish under a cooled CCD camera using a computer-controlled turntable. Each approach has distinct advantages.

Single mutations in sasA enable a simpler ΔcikA gene network architecture with equivalent circadian properties.

The circadian input kinase of the cyanobacterium Synechococcus elongatus PCC 7942 (CikA) is important both for synchronizing circadian rhythms with external environmental cycles and for transferring temporal information between the oscillator and the global transcriptional regulator RpaA (regulator of phycobilisome-associated A). KOs of cikA result in one of the most severely altered but still rhythmic circadian phenotypes observed. We chemically mutagenized a cikA-null S.

Prospective Optimization.

Human performance approaches that of an ideal observer and optimal actor in some perceptual and motor tasks. These optimal abilities depend on the capacity of the cerebral cortex to store an immense amount of information and to flexibly make rapid decisions. However, behavior only approaches these limits after a long period of learning while the cerebral cortex interacts with the basal ganglia, an ancient part of the vertebrate brain that is responsible for learning sequences of actions directed toward achieving goals.

A comprehensive wiring diagram of the protocerebral bridge for visual information processing in the Drosophila brain.

How the brain perceives sensory information and generates meaningful behavior depends critically on its underlying circuitry. The protocerebral bridge (PB) is a major part of the insect central complex (CX), a premotor center that may be analogous to the human basal ganglia. Here, by deconstructing hundreds of PB single neurons and reconstructing them into a common three-dimensional framework, we have constructed a comprehensive map of PB circuits with labeled polarity and predicted directions of information flow.

Neuroscience. The brain activity map.

Neuroscientists have made impressive advances in understanding the microscale function of single neurons and the macroscale activity of the human brain. One can probe molecular and biophysical aspects of individual neurons and also view the human brain in action with magnetic resonance imaging (MRI) or magnetoencephalography (MEG). However, the mechanisms of perception, cognition, and action remain mysterious because they emerge from the real-time interactions of large sets of neurons in densely interconnected, widespread neural circuits.

Biological indeterminacy.

Reductionist explanations in biology generally assume that biological mechanisms are highly deterministic and basically similar between individuals. A contrasting view has emerged recently that takes into account the degeneracy of biological processes--the ability to arrive at a given endpoint by a variety of available paths, even within the same individual. This perspective casts significant doubt on the prospects for the ability to predict behavior accurately based on brain imaging or genotyping, and on the ability of neuroscience to stipulate ethics.

The brain activity map project and the challenge of functional connectomics.

The function of neural circuits is an emergent property that arises from the coordinated activity of large numbers of neurons. To capture this, we propose launching a large-scale, international public effort, the Brain Activity Map Project, aimed at reconstructing the full record of neural activity across complete neural circuits. This technological challenge could prove to be an invaluable step toward understanding fundamental and pathological brain processes.

Genes involved in sex pheromone discrimination in Drosophila melanogaster and their background-dependent effect.

Mate choice is based on the comparison of the sensory quality of potential mating partners, and sex pheromones play an important role in this process. In Drosophila melanogaster, contact pheromones differ between male and female in their content and in their effects on male courtship, both inhibitory and stimulatory. To investigate the genetic basis of sex pheromone discrimination, we experimentally selected males showing either a higher or lower ability to discriminate sex pheromones over 20 generations.