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The relation between attention and consciousness is a highly debated topic in Cognitive Neuroscience. Although there is an agreement about their relationship at the functional level, there is still no consensus about how these two cognitive processes interact at the neural level. According to the gateway hypothesis (Posner, 1994), attention filters the information accessing to consciousness, resulting in both neural and functional modulations. Contrary to this idea, the cumulative influence hypothesis (Tallon-Baudry, 2012) proposes that both attention and consciousness independently impact decision processes about the perception of stimuli. Accordingly, we could observe an interaction between attention and consciousness at the behavioral level, but not at the neural level. Previous studies have shown that alerting and orienting networks of attention modulate participants’ ability to verbally report near-threshold visual stimuli both at behavioral and neural levels, supporting the gateway hypothesis over the cumulative influence hypothesis. The impact of the executive control network of attention on conscious perception, however, has only been explored behaviorally (Colás et al., 2017). In the present study, we employed high-density encephalography to investigate the neural basis of the interaction between executive attention and conscious perception. We presented a classical Stroop task concurrently with a detection task of near-threshold stimuli. In two separate sessions, we manipulated the proportion of congruent and incongruent Stroop stimuli. We found that the Stroop-evoked N2 potential (usually associated to conflict detection and localized in the anterior cingulate cortex) was modulated by both conflict detection and conscious perception processes. These results suggest that the relation between executive control and conscious perception lies in frontal lobe regions associated to conflict detection, supporting the gateway hypothesis over the cumulative influence hypothesis. [ABSTRACT FROM AUTHOR]

Working Memory (WM) maintains flexible representations. Retrospective cueing studies indicate that selective attention can be directed to memory representations in WM improving performance. While most of the work has explored the neural substrates of orienting attention based on a spatial retro-cue, behavioral studies show that a feature other than location can also improve WM performance. In the present work we explored the oscillatory underpinnings of orienting attention to a relevant representation held in WM guided by a feature value. We recorded EEG data in a group of 36 healthy human subjects (20 females) performing a WM task in which they had to memorize the orientation of four rectangles of different colors. After a maintenance period, a cue was presented indicating the color of the relevant item. We showed that directing attention to a memory item based on its color resulted in a modulation of posterior alpha activity, which appears as more desynchronization in the contralateral than in the ipsilateral hemisphere. Alpha lateralization is considered a neurophysiological marker of external and internal spatial attention. We propose that current findings support the idea that selection of a memory item based on a non-location feature could be accomplished by a spatial attentional mechanism. Moreover, using a centrally presented color retro-cue allowed us to surpass the confounds inherent to the use of spatial retro-cues, supporting that the observed lateralized alpha results from an endogenous attentional mechanism. [ABSTRACT FROM AUTHOR]

Background: Current theories suggest a role for frontal–striatal circuits in the pathogenesis of attention-deficit/hyperactivity disorder (ADHD). Methods: We used magnetoencephalography (MEG) to measure event-related brain activity during a simplified version of the Wisconsin Card Sorting Test in children with DSM-IV combined type ADHD (ADHD-C) or predominantly inattentive type ADHD (ADHD-PI) and in age- and intelligence-matched control children. Results: In control children, set-shifting cues evoked a higher degree of activation in the medial temporal lobe (MTL) between 200 and 300 msec than non-shifting cues, with MTL activation predicting later activity in left anterior cingulate cortex (ACC) (at 400–500 msec). This MTL–ACC response pattern was diminished in children with ADHD. By contrast, children with ADHD showed early activity in regions barely activated in control children, such as left inferior parietal lobe and posterior superior temporal gyrus. Conclusions: These preliminary data support theories of frontal dysfunction in ADHD but also suggest that deficits in higher-level functions might be secondary to disruptions in earlier limbic processes. [Copyright &y& Elsevier]

Abstract: The tip-of-the-tongue state (TOT) in face naming is a transient state of difficulty in access to a person''s name along with the conviction that the name is known. The aim of the present study was to characterize the spatio-temporal course of brain activation in the successful naming and TOT states, by means of magnetoencephalography, during a face-naming task. Following famous face presentations, subjects indicated whether they knew the name, did not know the name, or experienced a TOT state. Next they produced the name aloud, if they could, although they did not indicate whether they retrieved any other information about the person. The TOT state was characterized by lower activation than for successful retrieval, in the 310–520ms poststimulus interval, localized to left temporal and frontal areas, bilateral parahippocampal gyrus, and right fusiform gyrus, which may underlie the genesis of TOT. Greater activation was also found in the 740–820ms interval, localized to bilateral occipital, left temporal, and right frontal and parietal areas, corresponding with the unfruitful search for the name after the TOT state was produced. These results showed the differential brain dynamics underlying searching for the name of a known individual according to whether the search was successful or subjectively rated as just short of success. [Copyright &y& Elsevier]

Alcoholism is one of the most important problems today. Chronic alcohol intake produces many cognitive deficits in humans, especially in memory. To evaluate the memory deficits in alcoholism it is very common to use animal models. In the present work, rats receiving chronic alcohol intake and not submitted to withdrawal were evaluated in a spontaneous delayed nonmatching-to-sample test (EDNMS). Ninety-six male Wistar rats, 90 and 180 days old, were used in the experiment. Alcohol-treated rats (ALCY and ALCA) had free access to an aqueous ethanol solution as the only available liquid source from 21 days of age to the end of experiment for both groups (90 and 180 days). Animals were then evaluated in a nonspatial memory test based on the paradigm EDNMS using delays of 1, 15, and 60 min. The results show that chronic alcohol intake impairs the rats'' performance, both at 90 and 180 days old, in this test of object recognition when the delay interval is of 1 h. Chronic alcohol intake with no withdrawal periods produces memory deficits and these effects of alcohol begin in the early period of intake. Moreover, we may state that the paradigm of EDNMS with a delay interval of 60 min is useful to evaluate several cognitive deficits such as hippocampal-derived memory impairment. [Copyright &y& Elsevier]

Abstract: Mechanisms underlying exogenous attention to central and peripheral distracters were temporally and spatially explored while 30 participants performed a digit categorization task. Neural (event-related potentials—ERPs-, analyzed both at the scalp and at the voxel level) and behavioral indices of exogenous attention were analyzed. Distracters were either biologically salient or neutral, in order to test whether the exogenous attention bias to the former observed in previous studies is independent of, or interacts with, distracter eccentricity. Two subcomponents of the N2 component of the ERPs, N2olp and N2ft, reflected processes related to peripheral distracters processing. N2olp effects, located in the dorsal attention network (supplementary motor area), were probably related to covert reorientation to peripheral distracters. N2ft effects, located in the default mode network (posterior cingulate cortex), appeared to reflect less effort in the ongoing task when peripheral distracters were presented. N2ft also showed a biological saliency effect which was independent of eccentricity and was located in the polar/ventral prefrontal cortex. P3 showed greater amplitudes to centrally presented distracters. These latter effects were located in TEO (visual cortex), and would be functionally associated with spatial interference between the target and central distracters. Behavior showed the relevance of both central and peripheral distracters in exogenous attention. These results indicate that exogenous attention to peripheral distracters differed in temporal and spatial terms from exogenous attention to central distracters and that it is biased towards biologically salient events irrespective of their eccentricity. [Copyright &y& Elsevier]