Altered functional connectivity: A possible reason for reduced performance during visual cognition involving scene incongruence and negative affect.

Object-context associations and valence are two unavoidable stimulus characteristics when it comes to the processing of natural visual scenes. In line with our previous studies exploring the parallel processing of context-congruity and valence, in the current study, we investigated the valence-specific differences in functional connectivity between congruent-incongruent picture pairs during binocular rivalry using high-density EEG. The functional connectivity measure was calculated using sLORETA during the perceptual dominance of congruent and incongruent stimuli in a time window of 400 ms before the response and compared within and between positive, negative, and neutral valence categories (84 Brodmann's areas across 7 frequency bands) using t-tests. A significant difference in functional connectivity between congruent-incongruent picture pairs was seen only when associated with negative valence and a maximum number of area pairs showed differences in lower alpha 1 (7.1-9 Hz), upper alpha (11.1-13 Hz), and beta (13.1-30 Hz) frequency bands. The functional connectivity was significantly lower during incongruent perception between the area pairs which process mainly emotion, attention, memory, and semantic relations compared to their corresponding congruent stimuli. Similarly, negative incongruent percepts were found to have significantly lower connectivity between areas processing attention, emotion, and incongruence in the lower alpha 2 (9.1 -11 Hz) band when compared to positive incongruent percepts. Together, these results suggest that the perception of negative incongruence is associated with lower functional connectivity and this could be a possible reason for the increased error rates when faced with incongruity and negative affect during visual tasks.

Frontal activation as a key for deciphering context congruity and valence during visual perception: An electrical neuroimaging study.

The object-context associations and the valence are two important stimulus attributes that influence visual perception. The current study investigates the neural sources associated with schema congruent and incongruent object-context associations within positive, negative, and neutral valence during an intermittent binocular rivalry task with simultaneous high-density EEG recording. Cortical sourceswere calculated using the sLORETA algorithm in 150 ms after stimulus onset (Stim + 150) and 400 ms before response (Resp-400) time windows. No significant difference in source activity was found between congruent and incongruent associations in any of the valence categories in the Stim + 150 ms window indicating that immediately after stimulus presentation the basic visual processing remains the same for both. In the Resp-400 ms window, different frontal regions showed higher activity for incongruent associations with different valence such as the superior frontal gyrus showed significantly higher activations for negative while the middle and medial frontal gyrus showed higher activations for neutral and finally, the inferior frontal gyrus showed higher activations for positive valence. Besides replicating the previous knowledge of frontal activations in response to context congruity, the current study provides further evidence for the sensitivity of the frontal lobe to the valence associated with the incongruent stimuli.

State-dependent perception and perceptual reversals during intermittent binocular rivalry: An electrical neuroimaging study.

The object-context relationship and valence are two important stimulus attributes that affect visual perception. Although previous studies reveal how these two factors affect visual perception individually, the interplay between valence with congruent or incongruent object-context associations during visual perception is explored scarcely. Further, what is perceived, is affected by the intrinsic state of the brain at the moment of appearance of the stimulus which could be assessed by EEG microstates. Hence, the current study was designed to explore how the pre-stimulus EEG microstate influences the perception of emotional congruent and incongruent stimuli as well as perceptual reversals and stability during an intermittent binocular rivalry. Results revealed the association of specific pre-stimulus microstates with the perception of neutral and negative congruent stimuli as well as perceptual reversals and stability. Electrical neuroimaging of these microstates showed higher activation in the precuneus and middle occipital gyrus preceding the perception of neutral congruent stimuli and lingual gyrus preceding the perception of negative congruent stimuli. Increased source activity in superior temporal gyrus and superior frontal gyrus was found preceding stability and lower activation in parahippocampal gyrus was observed preceding reversals. Together these results suggest that the pre-stimulus activation of areas involved in visual priming, retrieval, and semantics leads to congruent perception. Pre-stimulus DMN suppression was required for perceptual reversals whereas stability was accompanied by pre-stimulus activation of areas related to the specific nature of the stimulus. Therefore, we propose that in addition to stimulus attributes, the pre-stimulus intrinsic brain activity could be an important determinant of the performance.

Does valence influence perceptual bias towards incongruence during binocular rivalry?

The efficient processing of complex visual environments is essential for effective functioning. In the natural environment, processing the context is as important as the processing of the target object since no object can be found in isolation. Congruent object-context associations in a visual scene facilitate object recognition, whereas incongruent associations decrease performance accuracy. Although there is a performance reduction, incongruent scenes are reported to have a perceptual bias due to the reallocation of the attentional resources towards the associated semantic conflict. Another key attribute that prepares the visual system to identify the important aspects of the environment is valence, and any visual scene can be classified into one of the three valence categories. Hence, the current study was designed to investigate how valence influences the perceptual bias towards incongruent object-context associations. An intermittent binocular rivalry task was used to measure the perceptual bias across valence categories. The results revealed a significant predominance of incongruent pictures when the associated valence was negative and neutral and remained unbiased for positive valence. We propose a valence-congruency interaction in which perceptual bias towards incongruence is greatly influenced by valence.