Endogenous recruitment of frontal-sensory circuits during visual discrimination

A long-range circuit linking anterior cingulate cortex (ACC) to primary visual cortex (V1) has been previously proposed to mediate visual selective attention in mice during visually guided behaviour. Here we used in vivo two-photon functional imaging to measure endogenous activity of ACC neurons projecting to layer 1 of V1 (ACC-V1axons) in mice either passively viewing stimuli or performing a go/no-go visually guided task. We observed that while ACC-V1axons were recruited under these conditions, this was not linked to enhancement of neural or behavioural measures of sensory coding. Instead, ACC-V1axon activity was observed to be associated with licking behaviour, modulated by reward, and biased towards task relevant sensory cortex.

Contributions of the Right Prefrontal and Parietal Cortices to the Attentional Blink: A tDCS Study

The AB refers to the performance impairment that occurs when visual selective attention is overloaded through the very rapid succession of two targets (T1 and T2) among distractors by using the rapid serial visual presentation task (RSVP). Under these conditions, performance is typically impaired when T2 is presented within 200–500 ms from T1 (AB). Based on neuroimaging studies suggesting a role of top-down attention and working memory brain hubs in the AB, here we potentiated via anodal or sham tDCS the activity of the right DLPFC (F4) and of the right PPC (P4) during an AB task. The findings showed that anodal tDCS over the F4 and over P4 had similar effects on the AB. Importantly, potentiating the activity of the right frontoparietal network via anodal tDCS only benefitted poor performers, reducing the AB, whereas in good performers it accentuated the AB. The contribution of the present findings is twofold: it shows both top-down and bottom-up contributions of the right frontoparietal network in the AB, and it indicates that there is an optimal level of excitability of this network, resulting from the individual level of activation and the intensity of current stimulation.

Working memory capacity, and selective attention in older children with mathematics learning disabilities

Both verbal and visuospatial working memory adding to selective attention, have been examined in two groups (Mean age = 12.59 years old). One of the two groups displaying math learning disabilities (n=36), this group acts as an experimental group, and the other group without learning disabilities acts as a control group (n=36), the two groups were matched for age and IQ. The two groups presented with complex span tasks to assess working memory capacity (WMC), operation span task (OSPAN) used to assess verbal working memory capacity, symmetry span task used to assess visuospatial working memory capacity; the two previous tasks administrated automatically by using computers. Selective attention assessed in the two groups by using a colored square task (CST) that used for assessing visual selective attention and it administrated automatically. Results revealed that the performance of children with MLD was lower than the control group (typically achieving children) in both verbal and visuospatial working memory, moreover, the two groups differed in the number of correct responses (accuracy) in visual selective attention for typically achieved children, but there is no significant difference between them in response time (speed).

EXPRESS: How the size of exogenous attentional cues alters visual performance: from response gain to contrast gain

The normalization model of attention (NMoA) predicts that the attention gain pattern is mediated by changes in the size of the attentional field and stimuli. However, existing studies have not measured gain patterns when the relative sizes of stimuli are changed. To investigate the NMoA, the present study manipulated the attentional field size, namely, the exogenous cue size. Moreover, we assessed whether the relative rather than the absolute size of the attentional field matters, either by holding the target size constant and changing the cue size (experiments 1-3) or by holding the cue size constant and changing the target size (experiment 4), in a spatial cueing paradigm of psychophysical procedures. The results show that the gain modulations changed from response gain to contrast gain when the precue size changed from small to large relative to the target size (experiments 1-3). Moreover, when the target size was once again made larger than the precue size, there was still a change in response gain (experiment 4). These results suggest that the size of exogenous cues plays an important role in adjusting the attentional field and that relative changes rather than absolute changes to exogenous cue size determine gain modulation. These results are consistent with the prediction of the NMoA and provide novel insights into gain modulations of visual selective attention.

Visual selective attention and the control of tracking eye movements: a critical review

People’s eyes are directed at objects of interest with the aim of acquiring visual information. However, processing this information is constrained in capacity, requiring task-driven and salience-driven attentional mechanisms to select few among the many available objects. A wealth of behavioral and neurophysiological evidence has demonstrated that visual selection and the motor selection of saccade targets rely on shared mechanisms. This coupling supports the premotor theory of visual attention put forth more than 30 years ago, postulating visual selection as a necessary stage in motor selection. In this review, we examine to which extent the coupling of visual and motor selection observed with saccades is replicated during ocular tracking. Ocular tracking combines catch-up saccades and smooth pursuit to foveate a moving object. We find evidence that ocular tracking requires visual selection of the speed and direction of the moving target, but the position of the motion signal may not coincide with the position of the pursuit target. Further, visual and motor selection can be spatially decoupled when pursuit is initiated (open-loop pursuit). We propose that a main function of coupled visual and motor selection is to serve the coordination of catch-up saccades and pursuit eye movements. A simple race-to-threshold model is proposed to explain the variable coupling of visual selection during pursuit, catch-up and regular saccades, while generating testable predictions. We discuss pending issues, such as disentangling visual selection from preattentive visual processing and response selection, and the pinpointing of visual selection mechanisms, which have begun to be addressed in the neurophysiological literature.

Cortical oscillations that underlie visual selective attention are abnormal in adolescents with cerebral palsy

Adolescence is a critical period for the development and refinement of several higher-level cognitive functions, including visual selective attention. Clinically, it has been noted that adolescents with cerebral palsy (CP) may have deficits in selectively attending to objects within their visual field. This study aimed to evaluate the neural oscillatory activity in the ventral attention network while adolescents with CP performed a visual selective attention task. Adolescents with CP (N = 14; Age = 15.7 ± 4 years; MACS I–III; GMFCS I–IV) and neurotypical (NT) adolescents (N = 21; Age = 14.3 ± 2 years) performed the Eriksen flanker task while undergoing magnetoencephalographic (MEG) brain imaging. The participants reported the direction of a target arrow that was surrounded by congruent or incongruent flanking arrows. Compared with NT adolescents, adolescents with CP had slower responses and made more errors regarding the direction of the target arrow. The MEG results revealed that adolescents with CP had stronger alpha oscillations in the left insula when the flanking arrows were incongruent. Furthermore, participants that had more errors also tended to have stronger alpha oscillatory activity in this brain region. Altogether these results indicate that the aberrant activity seen in the left insula is associated with diminished visual selective attention function in adolescents with CP.

Neuronal modulation in the mouse superior colliculus during covert visual selective attention

Covert visual attention is accomplished by a cascade of mechanisms distributed across multiple brain regions. Recent studies in primates suggest a parcellation in which visual cortex is associated with enhanced representations of relevant stimuli, whereas subcortical circuits are associated with selection of visual targets and suppression of distractors. Here we identified how neuronal activity in the superior colliculus (SC) of head-fixed mice is modulated during covert visual attention. We found that spatial cues modulated both firing rate and spike-count correlations, and that the cue-related modulation in firing rate was due to enhancement of activity at the cued spatial location rather than suppression at the uncued location. This modulation improved the neuronal discriminability of visual-change-evoked activity between contralateral and ipsilateral SC neurons. Together, our findings indicate that neurons in the mouse SC contribute to covert visual selective attention by biasing processing in favor of locations expected to contain relevant information.