A brief thought can modulate activity in extrastriate visual areas: Top-down effects of refreshing just-seen visual stimuli

Abstract

Current models of executive function hold that the internal representations of stimuli used during reflective thought are maintained in the same posterior cortical regions initially activated during perception, and that activity in such regions is modulated by top-down signals originating in prefrontal cortex. In an event-related functional magnetic resonance imaging study, we presented participants with two pictures simultaneously, a face and a scene, immediately followed either by a repetition of one of the pictures (perception) or by a cue to think briefly of one of the just-seen, but no longer present, pictures (refreshing, a reflective act). Refreshing faces and scenes modulated activity in the fusiform face area (FFA) and parahippocampal place area (PPA), respectively, as well as other regions exhibiting relative perceptual selectivity for either faces or scenes. Four sceneselective regions (lateral precuneus, retrosplenial cortex, PPA, and middle occipital gyrus) showed an anatomical gradient of responsiveness to top-down reflective influences versus bottom-up perceptual influences. These results demonstrate that a brief reflective act can modulate posterior cortical activity in a stimulus-specific manner, suggesting that such modulatory mechanisms are engaged even during transient ongoing thought. Our findings are consistent with the hypothesis that refreshing is a component of more complex modulatory operations such as working memory and mental imagery, and that refresh-related activity may thus contribute to the common activation patterns seen across different cognitive tasks.

The Executive Control of Face Memory

“…4). Furthermore, imaging evidence that levels of neural activity within temporal lobe face processing areas are modulated by top-down signals originating in PFC [16,24,34,58] is consistent with the notion that the frontal lobes exert executive control over the recognition process (Fig. 4).…”

Human electrophysiological reflections of the recruitment of perceptual processing during actions that engage memory

“…During a memory task, stored representations of relevant information must be recruited during recall (Goodale & Milner, 1992;Klatzky et al, 1993). Additionally, studies have shown that the process of remembering often reactivates sensoryspecific cortices that were first activated during the encoding of stimulus features (Johnson, Mitchell, Raye, D'Esposito, & Johnson, 2007;Geng, Ruff, & Driver, 2009). By directly comparing two conditions for which the contribution of the ventral stream is hypothesized to differ, we have shown that the N170 likely reflects perceptual requirements during mnemonic processing specifically linked to action.…”

Pruning of memories by context-based prediction error

“…Indeed, even the strongest predictions in the current task may result in only moderate activation: There is only a single opportunity to associate C items with their context, predictions were incidental with respect to the categorization task during encoding, and prediction is internally generated activation -such activation is weaker than perceptual activation in general (27). When activation levels fall in this low-to-moderate range, the nonmonotonic plasticity hypothesis posits that the relationship of item activation to memory will be negative: Weak predictions will be neutral, whereas stronger predictions (leading to moderate activation) will induce forgetting.…”

“…To test this idea, we related perception strength-i.e., classifier evidence for the C category in initial triplets-to subsequent memory. We expected that the perception of an item would elicit substantially higher activation levels than its later context-based prediction (27), leading to a positive relationship with subsequent memory.…”