The Tactile-Visual Conflict Processing and Its Modulation by Tactile-Induced Emotional States: An Event-Related Potential Study.

This experiment used event-related potentials (ERPs) to study the tactile-visual information conflict processing in a tactile-visual pairing task and its modulation by tactile-induced emotional states. Eighteen participants were asked to indicate whether the tactile sensation on their body matched or did not match the expected tactile sensation associated with the object depicted in an image. The type of tactile-visual stimuli (matched vs. mismatched) and the valence of tactile-induced emotional states (positive vs. negative) were manipulated following a 2 × 2 factorial design. Electrophysiological analyses revealed a mismatched minus matched negative difference component between 420 and 620 ms after stimulus onset in the negative tactile-induced emotional state condition. This ND420-620 component was considered as a sign of the cross-modal conflict processing during the processing of incongruent tactile-visual information. In contrast, no significant mismatched minus matched negative difference component was found in the positive tactile-induced emotional state condition. Together, these results support the hypothesis that a positive emotional state induced by a positive tactile stimulation improves tactile-visual conflict processing abilities.

Event-Related Brain Potentials Associated With the Olfactory-Visual Stroop Effect and Its Modulation by Olfactory-Induced Emotional States.

This study investigated the event-related brain potentials associated with the olfactory-visual cross-modal Stroop effect and its modulation by olfactory-induced and self-reported affective states. Eighteen healthy participants were presented with an olfactory stimulus and the image of a plant, and they had to categorize the olfactory attribute of the image as "aromatic" or "pungent" by pressing the relevant button as quickly as possible. The type of olfactory-visual stimuli (congruent or incongruent) and the valence of the olfactory-induced emotional states (positive or negative) were manipulated following a 2 × 2 factorial design. Interference effects were observed at the behavioral and the electrophysiological levels: response times recorded in the incongruent condition were higher than those observed in the congruent condition; an incongruent minus congruent negative difference component was discovered between 350 and 550 ms after stimulus onset in the negative-but not in the positive-olfactory-induced emotional state condition. This ND350-550 component was interpreted as reflecting the amount of selective attention involved in the olfactory-visual cross-modal Stroop effect. These results are also consistent with a facilitatory effect of positive emotional state on selective attention which could reduce brain potentials associated with the cross-modal interference effect.

Inducing the use of right eye enhances face-sex categorization performance.

Face recognition ability varies tremendously among neurologically typical individuals. What causes these differences is still largely unknown. Here, we first used a data-driven experimental technique-bubbles-to measure the use of local facial information in 140 neurotypical individuals during a face-sex categorization task. We discovered that the use of the eye and eyebrow area located on the right side of the face image from the observer's viewpoint correlates positively with performance, whereas the use of the left-eye and eyebrow area correlates negatively with performance. We then tested if performance could be altered by inducing participants to use either the right- or the left-eye area. One hundred of these participants thus underwent a 1-hr session of a novel implicit training procedure aimed at inducing the use of specific facial information. Afterward, participants repeated the bubbles face-sex categorization task to assess the changes in use of information and its effect on performance. Participants that underwent right-eye induction used this facial region more than they initially did and, as expected, improved their performance more than the participants who underwent the left-eye induction. This is the first clear evidence of a causal link between the use of specific face information and face recognition ability: Use of right-eye region not only predicts but causes better face-sex categorization. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The Neural Basis of Taste-visual Modal Conflict Control in Appetitive and Aversive Gustatory Context.

The functional magnetic resonance imaging (fMRI) technique was used to investigate brain activations related to conflict control in a taste-visual cross-modal pairing task. On each trial, participants had to decide whether the taste of a gustatory stimulus matched or did not match the expected taste of the food item depicted in an image. There were four conditions: Negative match (NM; sour gustatory stimulus and image of sour food), negative mismatch (NMM; sour gustatory stimulus and image of sweet food), positive match (PM; sweet gustatory stimulus and image of sweet food), positive mismatch (PMM; sweet gustatory stimulus and image of sour food). Blood oxygenation level-dependent (BOLD) contrasts between the NMM and the NM conditions revealed an increased activity in the middle frontal gyrus (MFG) (BA 6), the lingual gyrus (LG) (BA 18), and the postcentral gyrus. Furthermore, the NMM minus NM BOLD differences observed in the MFG were correlated with the NMM minus NM differences in response time. These activations were specifically associated with conflict control during the aversive gustatory stimulation. BOLD contrasts between the PMM and the PM condition revealed no significant positive activation, which supported the hypothesis that the human brain is especially sensitive to aversive stimuli. Altogether, these results suggest that the MFG is associated with the taste-visual cross-modal conflict control. A possible role of the LG as an information conflict detector at an early perceptual stage is further discussed, along with a possible involvement of the postcentral gyrus in the processing of the taste-visual cross-modal sensory contrast.

Paper features: a neglected source of information for letter recognition.

Adult observers have surprisingly low calculation efficiencies for letter recognition (see, e.g., Pelli, Burns, Farell, & Moore-Page, 2006). Here, we examine the possibility that this is partly due to observers' neglecting paper features (e.g., the absence of ascenders and descenders in 'o'). Each of 16 observers completed 5,000 trials of a single-letter two-alternative forced-choice detection task. Using a combination of classification image analyses and Bayesian statistical analyses, we argue that between 60% and 75% of our participants indeed neglected paper features.

Real-world interattribute distances lead to inefficient face gender categorization.

The processing of interattribute distances is believed to be critical for upright face categorization. A recent study by Taschereau-Dumouchel, Rossion, Schyns, and Gosselin (2010) challenged this idea by showing that participants were nearly at chance when asked to identify faces on the sole basis of real-world interattribute distances, while they were nearly perfect when all other facial cues were shown. However, it remains possible that humans are highly tuned to interattribute distances but that the information conveyed by these cues is scarce. We tested this hypothesis by contrasting the efficiencies-a measure of performance that factors out task difficulty-of 60 observers in 6 face gender categorization tasks. Our main finding is that efficiencies for faces that varied only in terms of their interattribute distances were an order of magnitude lower than efficiencies for faces that varied in all respects, except their interattribute distances, or in all respects. These results provide a definitive blow to the idea that real-world interattribute distances are critical for upright face processing. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Exposure to traumatic experiences is associated with abnormal neural mechanism during charitable donation.

Previous studies suggested that posttraumatic stress disorder (PTSD) might be associated with dysfunctional reward processing. At present, little is known about the neural mechanisms of reward-related processing during a charitable donation task in trauma survivors who do not go on to develop PTSD. We used functional magnetic resonance imaging (fMRI) to investigate the neural basis of charitable donation in non-PTSD survivors of the Sichuan earthquake. Results showed that activations in the striatum of trauma survivors were reduced in both the low donation (donated a small amount to the Red Cross) and the high donation conditions (donated a large amount to the Red Cross) compared with the healthy controls. Furthermore, the trauma survivors also exhibited less activity in the insula than the healthy controls in the high donation condition. These findings suggest that abnormal reward-related activations might be associated with dysfunctions in the reward pathway of trauma survivors. Also, we discuss the possibility that traumatic experiences attenuate the reactivity of reward-related brain areas to positive emotions (as induced by advantageous donations).

Reading laterally: the cerebral hemispheric use of spatial frequencies in visual word recognition.

It is generally accepted that the left hemisphere (LH) is more capable for reading than the right hemisphere (RH). Left hemifield presentations (initially processed by the RH) lead to a globally higher error rate, slower word identification, and a significantly stronger word length effect (i.e., slower reaction times for longer words). Because the visuo-perceptual mechanisms of the brain for word recognition are primarily localized in the LH (Cohen et al., 2003), it is possible that this part of the brain possesses better spatial frequency (SF) tuning for processing the visual properties of words than the RH. The main objective of this study is to determine the SF tuning functions of the LH and RH for word recognition. Each word image was randomly sampled in the SF domain using the SF bubbles method (Willenbockel et al., 2010) and was presented laterally to the left or right visual hemifield. As expected, the LH requires less visual information than the RH to reach the same level of performance, illustrating the well-known LH advantage for word recognition. Globally, the SF tuning of both hemispheres is similar. However, these seemingly identical tuning functions hide important differences. Most importantly, we argue that the RH requires higher SFs to identify longer words because of crowding.

Neural correlates of the modified Stroop effect in post-traumatic stress disorder: an event-related potential study.

Previous studies have provided electrophysiological evidence for attentional abnormalities in patients with post-traumatic stress disorder (PTSD). The present study examined the electrophysiological activity of trauma-exposed patients with or without a PTSD during a modified Stroop task. The PTSD group showed a reduced P2 and P3 amplitude relative to the non-PTSD group under both the earthquake-related and earthquake-unrelated words conditions. Importantly, the earthquake-related words elicited a greater P3 amplitude (350-450 ms after stimulus) than did unrelated words in the non-PTSD group, whereas no significant difference was found in the PTSD group. This indicates that PTSD patients had some attention deficits compared with non-PTSD individuals, and that these attention deficits were not just limited to earthquake-related words.

Uncovering gender discrimination cues in a realistic setting.

Which face cues do we use for gender discrimination? Few studies have tried to answer this question and the few that have tried typically used only a small set of grayscale stimuli, often distorted and presented a large number of times. Here, we reassessed the importance of facial cues for gender discrimination in a more realistic setting. We applied Bubbles-a technique that minimizes bias toward specific facial features and does not necessitate the distortion of stimuli-to a set of 300 color photographs of Caucasian faces, each presented only once to 30 participants. Results show that the region of the eyes and the eyebrows-probably in the light-dark channel-is the most important facial cue for accurate gender discrimination; and that the mouth region is driving fast correct responses (but not fast incorrect responses)-the gender discrimination information in the mouth region is concentrated in the red-green color channel. Together, these results suggest that, when color is informative in the mouth region, humans use it and respond rapidly; and, when it's not informative, they have to rely on the more robust but more sluggish luminance information in the eye-eyebrow region.

Perceptual learning without signal.

Perceptual learning is characterized by an improvement in a perceptual task following practice. Several studies have demonstrated that top-down processes, such as attention and task-related expectations, can be necessary components of perceptual learning [Ahissar & Hochstein, 1993, 2000, 2002; Fahle & Morgan, 1996; Seitz, Lefebvre, Watanabe, & Jolicoeur, 2005; Seitz, Nanez, Holloway, Koyama, & Watanabe, 2005; Seitz & Watanabe, 2003; Shiu & Pashler, 1992]. Here, we report an experiment that isolated top-down processes in perceptual learning, using a variant of the Gosselin and Schyns (1992) no-signal procedure. Results indicate that top-down processes can be sufficient to produce substantial, possibly long-lasting and rotation-invariant perceptual learning.