Mental workload and neural efficiency quantified in the prefrontal cortex using fNIRS

Mickael Causse (1, 2) , Zarrin Chua (1) , Vsevolod Peysakhovich (1) , Natalia del Campo (3, 4, 5) , Nadine Matton (6, 7)

1 DCAS - Département Conception et conduite des véhicules Aéronautiques et Spatiaux
2 ULaval - Université Laval [Québec]
3 NeuroToul - Centre d’Excellence en Maladies Neurodégénératives
4 CAM - University of Cambridge [UK]
5 ToNIC - Toulouse NeuroImaging Center
6 ENAC - Ecole Nationale de l'Aviation Civile
7 CLLE-LTC - Cognition, Langues, Langage, Ergonomie

An improved understanding of how the brain allocates mental resources as a function of task difficulty is critical for enhancing human performance. Functional near infrared spectroscopy (fNIRS) is a fielddeployable optical brain monitoring technology that provides a direct measure of cerebral blood flow in response to cognitive activity. We found that fNIRS was sensitive to variations in task difficulty in both real-life (flight simulator) and laboratory settings (tests measuring executive functions), showing increased concentration of oxygenated hemoglobin (HbO2) and decreased concentration of deoxygenated hemoglobin (HHb) in the prefrontal cortex as the tasks became more complex. Intensity of prefrontal activation (HbO2 concentration) was not clearly correlated to task performance. Rather, activation intensity shed insight on the level of mental effort, i.e., how hard an individual was working to accomplish a task. When combined with performance, fNIRS provided an estimate of the participants’ neural efficiency, and this efficiency was consistent across levels of difficulty of the same task. Overall, our data support the suitability of fNIRS to assess the mental effort related to human operations and represents a promising tool for the measurement of neural efficiency in other contexts such as training programs or the clinical setting.

Mots clés: Mental workload; FNIRS; Prefrontal cortex; Human Factors; Neuroergonomics

Domaines: Neurosciences

Mickael Causse, Zarrin Chua, Vsevolod Peysakhovich, Natalia del Campo, Nadine Matton. Mental workload and neural efficiency quantified in the prefrontal cortex using fNIRS. Scientific Reports, 2017, 7 (1), pp.1-15. ⟨10.1038/s41598-017-05378-x⟩. ⟨hal-01565168⟩