Medial orbitofrontal, prefrontal and amygdalar circuits support dissociable component processes of risk/reward decision making.

The medial orbitofrontal cortex (mOFC) has been implicated in shaping decisions involving reward uncertainty, in part by using memories to infer future outcomes. This region is interconnected with other key systems that mediated these decisions, including the basolateral amygdala (BLA) and prelimbic (PL) region of the medial prefrontal cortex, yet the functional importance of these circuits remains unclear. The present study used chemogenetic silencing to examine the contribution of different input and output pathways of the mOFC to risk/reward decision making.

Experimental and Theoretical Exploration of the Kinetics and Thermodynamics of the Nucleophile-Induced Fragmentation of Ylidenenorbornadiene Carboxylates.

Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with thiol nucleophiles to yield mixtures of four to eight diastereomers depending on the symmetry of the YND substrate. The mixtures of diastereomers fragment via a retro-[4 + 2] cycloaddition with a large variation in rate, with half-lives ranging from 16 to 11,000 min at 80 °C. The diastereomer-enriched samples of propane thiol adducts [YND-propanethiol (PTs)] were isolated and identified by nuclear Overhauser effect spectroscopy (NOESY) correlations.

Generation of a measurable magnetic field in a metal asteroid with a rubble-pile core.

Paleomagnetic records of iron meteorites of the IVA group suggest that their parent body (an inward-solidified metal asteroid) possessed an internal magnetic field. The origin of this magnetism is enigmatic because inward solidification typically leads to light element release from the top of the liquid, which depresses convection and dynamo activity. Here, we propose a possible scenario to help resolve this paradox.

Temporal Dynamics Underlying Prelimbic Prefrontal Cortical Regulation of Action Selection and Outcome Evaluation during Risk/Reward Decision-Making.

Risk/reward decision-making is a dynamic process that includes periods of deliberation before action selection and evaluation of the action outcomes that bias subsequent choices. Inactivation of the prelimbic (PL) cortex has revealed its integral role in updating decision biases in the face of changes in probabilistic reward contingencies, yet how phasic PL signals during different phases of the decision process influence choice remains unclear. We used temporally specific optogenetic inhibition to selectively disrupt PL activity coinciding with action selection and outcome phases to examine how these signals influence choice.

Ylidenenorbornadiene Carboxylates: Experimental Kinetic Analysis of a Nucleophile-Induced Fragmentation Reaction.

Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with -mercaptoethanol to yield a mixture of four diastereomers. These four diastereomers fragment via a retro-[4 + 2] cycloaddition at differing rates. A simulated kinetics approach extrapolated the rate constants of the diastereomers from the observed rate data.