ALERT AND FOCUSED

"Arousal, cortical signal-to-noise, and the ability to sustain attention"

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 Obiettivo del progetto (Objective)

'Sustained attention or the ability to maintain an alert, goal-directed focus is critical for many levels of human behavior. Failures of sustained attention occur when there is a transient decrease in endogenous control of behavior leaving one prone to goal-neglect and distraction by irrelevant stimuli. Frequent lapses in sustained attention are a core feature of performance in the elderly, sleep-deprived individuals, and patients with brain injury and mental disorders with attentional components, such as attention-deficit hyperactivity disorder and schizophrenia. Even healthy individuals differ substantially in their ability to sustain attention. Recent studies have linked deficits in sustaining attention to less stable (i.e., more noisy) cortical signals in particular in frontal brain areas. Although recent research has shed light on the neural mechanisms underlying lapses of attention, less is known about how an individual’s ability to sustain attention might be improved. This knowledge is clearly imperative for the development of interventions that can address sustained attention deficits in patients or for individuals who are prone to attentional lapses due to e.g., disturbed sleeping patterns. The aim of this research project is to study the neural and neurochemical mechanisms underlying the ability to maintain an alert, goal-directed focus, and the effects of an alertness training strategy on this ability. We propose to conduct three studies that will test our main hypothesis that increased volitional control of arousal during sustained attention task performance will enhance cortical signal stability, and thereby attentional stability. The third study will examine the effects of the noradrenergic agonist clonidine on the hypothesized interaction between arousal and attention. The proposed research will use a unique multidisciplinary combination of techniques from psychophysiology, neuroscience (EEG and fMRI), psychology, and pharmacology.'

Introduzione (Teaser)

Ability to stay goal-oriented, and stay alert differs among individuals. A recent European study has delved into neuronal mechanisms behind sustained attention..

Descrizione progetto (Article)

The elderly and sleep-deprived as well as people with brain injury and mental disorders such as attention-deficit hyperactivity disorder and schizophrenia lack this ability. The EU-funded 'Arousal, cortical signal-to-noise, and the ability to sustain attention' (ALERT AND FOCUSED) project was initiated to understand neural mechanisms involved in maintaining sustained attention and assess the effects of alertness training.

Electroencephalography (EEG) and skin conductance response (SCR) measurements were used to identify neural mechanisms involved in sustained attention in 32 subjects. They were given a time-intensive task to perform for 80 minutes with monetary motivation being offered after 60 minutes.

Assessment revealed a reduction in arousal and cortical signal stability over time in the frontal and occipital scalp regions. This corresponds with poorer performance and lapse in attention. Motivation only partially improved performance for a brief period, suggesting that performing prolonged tasks can affect cognitive control.

However, the use of compensatory neural mechanisms to consciously focus on tasks cannot be completely discounted. Surprisingly, no association was found between SCR recordings of arousal and variations in attentional stability and performance.

In contrast to results from previous EEG studies where bilateral attentional modulations were seen, early stimulus-evoked event-related potentials (ERPs) were only seen in one brain hemisphere. In other words, sustained attention to one location in space produced completely lateralised early ERPs in the posterior occipital cortex. This could be indicative of top-down modulations of feed-forward sensory processing. Further studies are required to explore the influence of task structure on attentional control dynamics and stimulus processing.

Project activities have confirmed the link between attention deficits and unstable cortical signals in the frontal and visual brain areas. The study of underlying neural mechanisms also provided new insights into therapeutic options with potential. This has important applications in the educational and clinical domain, particularly in the rehabilitation of patients with brain injury or mental disorders.