Attention and Consciousness

We are interested in exploring how our conscious perception is modulated by different attentional subsystems, such as spatial orienting, alerting, or executive control. By manipulating different attentional mechanisms and exploring their effects on conscious perception, we aim at better understanding how information is selected from our crowded environment to create our conscious experience (see Chica et al., 2012, Frontiers in Psychology).

We pay especial attention to the brain mechanisms subserving attention and consciousness interactions, and explore attentional mechanisms and conscious perception in brain damaged patients and in healthy controls using a variety of methods, such as functional Magnetic Resonance Imaging (fMRI), electroencephalographic recordings (EEG), and Transcranial Magnetic Stimulation (TMS).

We have demonstrated that conscious perception is facilitated by attentional orienting thanks to the activation of a distributed fronto-parietal network (Chica et al., 2013, Cerebral Cortex); alerting and consciousness interact in a fronto-striatal network (Chica et al., 2016, Scientific Reports); and executive attention modulates conscious perception due to the activation of frontal structures such as the anterior cingulated cortex (Colás et al., 2018, Neuropsychologia).

 

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Endogenous and exogenous attention

Orienting of attention in space can be controlled either endogenously (which is also known as top-down or voluntary attention), or exogenously, by external stimulation (bottom-up, involuntary stimulus-driven attention).

In this line of research, we explore the conditions where these two mechanisms are independent, produce different effects on information processing, and are supported by partially different brain regions.

We have largely explored the effects of both types of attention in the healthy population (see Chica et al., 2013, Behavioural Brain Research), but also in patients with brain damage (see e.g. Bourgeois et al., 2013, Cortex; Bourgeois et al., 2015, Neuropsychologia). We have used TMS to explore the neural bases of both types of attention (Chica et al., 2011, Journal of Neuroscience) and have discovered that endogenous and exogenous attention are implemented in partially overlapping, but different, brain regions.


White matter contributions to cognitive processes in the damaged and the healthy brain

Damage to localized brain regions can produce important impairments in both attention and consciousness. But damage to white matter pathways can also produce important deficits. The disconnections of a white matter fascicule connecting the parietal and the frontal lobe (the Superior Longitudinal Fascicule, SLF) has been demonstrated to cause hemispatial neglect, a syndrome characterized by significant impairments in both attention and consciousness.

Interesting, the integrity of white matter tracks in healthy individuals also correlates with their cognitive abilities. We have demonstrated that the integrity of the SLF in the healthy brain correlates with the activation of brain functional networks associated to attentional orienting and alerting (Chica et al., 2018, Brain Structure and Function). When using Transcranial Magnetic Stimulation in healthy participants, the integrity of the SLF also correlates with the TMS effects observed (Martín-Signes et al., 2017, Cerebral Cortex).

Understanding the role of white matter connections in the healthy and damaged brain seems therefore essential in the study of attention and consciousness.

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