Aversive Learning Enhances Perceptual and Cortical Discrimination of Indiscriminable Odor Cues

Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
Science (Impact Factor: 33.61). 04/2008; 319(5871):1842-5. DOI: 10.1126/science.1152837
Source: PubMed


Learning to associate sensory cues with threats is critical for minimizing aversive experience. The ecological benefit of associative learning relies on accurate perception of predictive cues, but how aversive learning enhances perceptual acuity of sensory signals, particularly in humans, is unclear. We combined multivariate functional magnetic resonance imaging with olfactory psychophysics to show that initially indistinguishable odor enantiomers (mirror-image molecules) become discriminable after aversive conditioning, paralleling the spatial divergence of ensemble activity patterns in primary olfactory (piriform) cortex. Our findings indicate that aversive learning induces piriform plasticity with corresponding gains in odor enantiomer discrimination, underscoring the capacity of fear conditioning to update perceptual representation of predictive cues, over and above its well-recognized role in the acquisition of conditioned responses. That completely indiscriminable sensations can be transformed into discriminable percepts further accentuates the potency of associative learning to enhance sensory cue perception and support adaptive behavior.

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Available from: Wen Li, Oct 01, 2015
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    • "In addition to single cell responses, overall dynamics in olfactory structures are also strongly modulated by discrimination learning (Beshel et al., 2007; Kay and Beshel, 2010; Kay and Lazzara, 2010; Martin, et al., 2007). In invertebrates, neural correlates of olfactory discrimination learning have been reported in both the antennal lobe and mushroom body structures (Silbering and Galizia, 2007; Silbering et al., 2008; Szyszka et al., 2005). In summary, discrimination learning is a distributed process across many brain structures and is modulated by stimulus and task parameters, previous experience with odorants, and manipulations of specific neurotransmitter and neuromodulator systems. "
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    • "Following pairing of a visual cue with a painful stimulus applied to the abdomen, IBS patients had higher skin conductance responses during extinction compared to controls (Labus et al., 2013). Further support for altered fear learning and extinction comes from studies on anxiety disorders which often co-occur with chronic pain (Bouton et al., 2001; Lissek et al., 2005; Mineka and Oehlberg, 2008). 1.3. "
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    • "This might be advantageous in allowing a quicker responding to a stimulus that has been predictive of danger in the past. It has been suggested that a network of extinction resistant neurons within the sensory cortex (Armony et al., 1998; Li et al., 2008) and lateral nucleus of the amygdala (Repa et al., 2001) act together to reengage the amygdala when threat reappears. This is based on evidence that, following extinction, the memory of the emotional event is persistent in the amygdala, as evident by neurons in the lateral nucleus that remain responsive to the CS+ even after extinction (Repa et al., 2001). "
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