Stability and flexibility of the message carried by semiochemical stimuli, as revealed by devaluation of carbon disulfide followed by social transmission of food preference.

Abstract

Semiochemicals are volatile compounds that communicate specific meaning between individuals, and elicit specific behavioral and/or physiological responses mediated by highly sensitive and highly specific olfactory pathways. Recent work suggests that semiochemicals can activate multiple olfactory pathways at once, but the degree to which parallel pathways activated by the same semiochemical interact, and what the behavioral consequences of such interactions are, remains a topic of debate. Here we approached this question behaviorally, investigating whether rats could be trained to avoid carbon disulfide (CS2) via taste-potentiated odor aversion, and asking whether any such learning would have an impact on the rats’ subsequent use of CS2 as a semiochemical cue (i.e., in a socially transmitted food preference paradigm). The results show that CS2-mediated food preference learning is unimpaired by aversions conditioned to CS2, a result indicating that canonical and semiochemical pathways for the processing of CS2 function in a largely independent manner.

Sensory Cortical Activity Is Related to the Selection of a Rhythmic Motor Action Pattern

“…6), causing our optogenetic result to appear smaller than it really is. Perhaps the 40 mW laser caused a mild intrinsic change in neural excitability that runs counter to the impact of inhibition via ArchT-a possibility consistent with results from another recent study (Maier et al, 2015). Alternatively, perhaps the bleed of laser light into the chamber during light-on trials slightly reduced the attention paid to the taste.…”

“…We calculated the fraction of neurons (of 161 neurons) whose responses encoded palatabilityrelated information as a function of time following taste delivery and did the same for the concurrently recorded EMG responses (n ϭ 20). Both functions were normalized to their maximal values to facilitate comparison of their time courses (black and green lines), which allows us to show that, consistent with earlier studies Piette et al, 2012;Sadacca et al, 2012;Maier and Katz, 2013), correlations with palatability begin to emerge in the GC population at 0.5 s (Fig. 2D, the green line diverges from zero at this time).…”

“…For each neuron recorded in the no-cue experiments, we used a moving window analysis to identify the times at which the responses of the neuron were palatability related. We defined "palatability relatedness" as we have previously (Piette et al, 2012;Sadacca et al, 2012;Maier and Katz, 2013), as follows: the extent to which the magnitude of the responses of the neuron to each of the four taste stimuli reflects (i.e., correlates with) the palatability ordering of the stimuli. For a given neuron, we first binned the spike train produced by the neuron following each taste delivery (span, 0 to 2.75 s) using partially overlapping time windows (window size, 1 s; step size, 0.1 s).…”

“…After 2 d of adaptation, distilled water was replaced with a 0.15% saccharin solution, and the laser was turned on for 2.5 s following each saccharin delivery (i.e., training day). Once the animal had consumed 6 ml of the solution, we induced gastric malaise by injecting 0.6 M lithium chloride (1% body weight, dissolved in distilled water, similar to concentrations and amounts used in other studies; Nachman and Ashe, 1973;Misanin and Hinderliter, 1994;Maier et al, 2014) into the intraperitoneal cavity. The following day (testing day), we returned the animal to the behavioral chamber, and recorded the number of times the animal poked for saccharin within a 30 min period.…”

Chemostimuli for guanylyl cyclase-D-expressing olfactory sensory neurons promote the acquisition of preferences for foods adulterated with the rodenticide warfarin

“…This avoidance is inhibited if the experienced rat is paired with another rat in a “safe” chamber where no foot shocks are given (Masuda and Aou, 2009 ). Furthermore, devaluation of the odor used as a social cue (e.g., CS 2 ) by pairing it with an aversive taste cue does not eliminate that odor's ability to elicit the acquisition of food preferences (Maier et al, 2014 ).…”