Experiments on scene perception and change blindness suggest that the visual system does not construct detailed internal models of a scene. These experiments therefore call into doubt the traditional view that vision is a process in which detailed representations of the environment must be constructed. The non-existence of such detailed representations, however, does not entail that we do not perceive the detailed environment. The “grand illusion hypothesis” that our visual world is an illusion rests on (1) a problematic “reconstructionist” conception (...) of vision, and (2) a misconception about the character of perceptual experience. (shrink)
The resurgent science of consciousness has been accompanied by a recent emphasis on the problem of measurement. Having dependable measures of consciousness is essential both for mapping experimental evidence to theory and for designing perspicuous experiments. Here, we review a series of behavioural and brain-based measures, assessing their ability to track graded consciousness and clarifying how they relate to each other by showing what theories are presupposed by each. We identify possible and actual conflicts among measures that can stimulate new (...) experiments, and we conclude that measures must prove themselves by iteratively building knowledge in the context of theoretical frameworks. Advances in measuring consciousness have implications for basic cognitive neuroscience, for comparative studies of consciousness and for clinical applications. (shrink)
Lindquist et al. provide a convincing case against what they call the locationist account of emotion. Their quantitative approach elegantly illustrates the shortcomings of this still-entrenched viewpoint. Here, I discuss how a network perspective will advance our understanding of structure-function mappings in general, and the relationship between emotion and cognition in the brain.
Cognition and emotion interact in important ways to shape ongoing behaviors. In this study, we investigated the interaction between conflict-driven executive control adjustments and emotion during a face-word Stroop-like paradigm. Neutral and negative images were employed to manipulate emotion. We were particularly interested in contrasting two hypotheses of the impact of emotion on conflict adaptation effects. On the one hand, resource accounts of cognitive-emotional interactions predict that behavioral adjustments following incongruent trials would be decreased when participants also have to process (...) a negative stimulus. On the other hand, affect regulation models predict that negative emotion should increase behavioral adjustments. We found that task-irrelevant negative stimuli significantly reduced conflict-driven control effects (i.e., conflict adaptation) compared to neutral images. We interpret the findings in terms of shared resources between proactive control mechanisms and emotional processing. Our findings demonstrate that emotion interacts with executive mechanisms responsible for dynamic behavioral adjustments that are tied to environmental demands, a central facet of flexible, goal-directed behavior. (shrink)
Research on emotion has considered the pulvinar to be an important component of a subcortical pathway conveying visual information to the amygdala in a largely “automatic” fashion. An older literature has focused on understanding the role of the pulvinar in visual attention. To address the inconsistency between these independent literatures, in the present study, we investigated how pulvinar responses are involved in the processing of affectively significant stimuli and how they are influenced by stimulus visibility during attentionally demanding conditions. Subjects (...) performed an attentional blink task during fMRI scanning involving affectively significant (CS+) and neutral stimuli (CS-). Pulvinar responses were not influenced by affective significance (CS+ vs. CS-) per se. Instead, evoked responses were only modulated by affective significance during HIT trials, but not during MISS trials. Importantly, moment-to-moment fluctuations in response magnitude closely tracked trial-by-trial detection performance, and thereby visibility. This relationship was only reliably detected during the affective condition. Our results do not support a passive role of the pulvinar in affective processing, as invoked in the context of the subcortical-pathway hypothesis. Instead, the pulvinar appears to be involved in mechanisms that are closely linked to attention and awareness. As part of thalamocortical loops with diverse cortical territories, we argue that the medial pulvinar is well positioned to influence information processing in the brain according to a stimulus’s biological significance. In particular, when weak and/or brief visual stimuli have affective significance, cortico-pulvino-cortical circuits may act to coordinate and amplify signals in a manner that enhances their behavioral impact. (shrink)
We investigated how the brain integrates motivational and attentional signals by using a neuroimaging paradigm that provided separate estimates for transient cue- and target-related signals, in addition to sustained block-related responses. Participants performed a Posner-type task in which an endogenous cue predicted target location on 70% of trials, while motivation was manipulated by varying magnitude and valence of a cash incentive linked to task performance. Our findings revealed increased detection performance (d’) as a function of incentive value. In parallel, brain (...) signals revealed that increases in absolute incentive magnitude led to cue- and target-specific response modulations that were independent of sustained state effects across visual cortex, fronto-parietal regions, and subcortical regions. Interestingly, state-like effects of incentive were observed in several of these brain regions, too, suggesting that both transient and sustained fMRI signals may contribute to task performance. For both cue and block periods, the effects of administering incentives were correlated with individual trait measures of reward sensitivity. Taken together, our findings support the notion that motivation improves behavioral performance in a demanding attention task by enhancing evoked responses across a distributed set of anatomical sites, many of which have been previously implicated in attentional processing. However, the effect of motivation was not simply additive as the impact of absolute incentive was greater during invalid than valid trials in several brain regions, possibly because motivation had a larger effect on reorienting than orienting attentional mechanisms at these sites. (shrink)
(1) The main issue with regard to modal and amodal completion is not which phenomena are cognitive, and which perceptual. At the level of the animal, both are visuo-cognitive. At the level of visual processing, however, we need to dissect the different functional effects of these kinds of completion. (2) Resonant binding between distributed cortical areas may play a role in perceptual completion, but evidence is needed.