Brain Correlates of Experience-Dependent Changes in Stimulus Discrimination Based on the Amount and Schedule of Exposure

Abstract

One product of simple exposure to similar visual stimuli is that they become easier to distinguish. The early visual cortex and other brain areas (such as the prefrontal cortex) have been implicated in such perceptual learning effects, but the anatomical specificity within visual cortex and the relationship between sensory cortex and other brain areas has yet to be examined. Moreover, while variations in the schedule (rather than merely the amount) of exposure influence experience-dependent improvement in discrimination, the neural sequelae of exposure schedule have not been fully investigated. In an event-related fMRI study, participants were exposed to confusable pairs of faces, scenes and dot patterns, using either intermixed or blocked presentation schedules. Participants then performed same/different judgements with exposed and novel pairs of stimuli. Stimulus independent activation, which was correlated with experience-dependent improvement in discrimination, was seen in frontal areas (e.g. frontal and supplementary eye fields and dorsolateral prefrontal cortex) and in early visual cortex (V1-4). In all regions, the difference in activation between exposed and novel stimuli decreased as a function of the degree of discrimination improvement. Overall levels of BOLD activation differed across regions, consistent with the possibility that, as a consequence of experience, processing shifts from initial engagement of early visual regions to higher order visual areas. Similar relationships were observed when contrasting intermixed with blocked exposure, suggesting that the schedule of exposure primarily influences the degree of, rather than the mechanisms for, discrimination performance.

Olfactory fear conditioning non-specifically enhances glomerular odor responses and increases representational overlap of learned and neutral odors

“…In fact, decorrelated cortical representations of odor mixtures predict behavioral discrimination of those mixtures (Barnes et al, 2011), reinforcing the idea that olfactory representational similarity confers perceptual similarity in a way that influences behavior. Similar learning-induced effects are reported in other sensory and model systems, confirming that sensory learning alters sensory processing and correlates with behavior (Edeline et al, 1993;Mukai et al, 2007;Mundy et al, 2014;Smith et al, 2015). Taken all together, any learning-induced transformation, even at the earliest stages of processing, that increases or decreases the representational similarity of sensory stimuli may prime generalized or specific behavioral responses, respectively.…”

The theory of general acuity: A psychophysical application to noncognitive measurement free from introspective self-report.

“…General acuity theory proposes that with practice and exposure to many examples of CR phenomena comes familiarity, comfortableness, development of coping strategies, and ultimately increased standing on the construct. But such practice and exposure also by definition makes one sensitive to distinctions in CR phenomena if the literature on the link between (a) exposure to phenomena and (b) discrimination between instances of that phenomena, has any validity (Fahle, 2004; Gilbert, Sigman, & Crist, 2001; Goldstone, 1998; Hall, 1991; Mundy et al, 2014). It is reasonable, therefore, that standing on any construct (e.g., integrity/honesty, cultural sensitivity, tranquility) may be enhanced by acuity training on CR phenomena differentiation.…”

Reward Region Responsivity Predicts Future Weight Gain and Further Evidence that the TaqIA Allele Moderates these Predictive Effects

“…Lower vmPFC volume has been associated with greater impulsive behavior (Boes et al, 2009). Activity in visual processing regions and vmPFC initially has been found to increase due to allocation of attention to novel events, but decreases over time due to a learning-related transition (Goldstein et al, 2007;Mundy et al, 2014). Weight gainers may have shown greater neural learning or habituation responses to the palatable food cues, perhaps due to a stronger food reward-cue learning propensity or prior experience with palatable food, consistent with the positive relation between lateral OFC response to anticipatory milkshake receipt and future body fat gain.…”