Neural Correlates of Cognitive Fatigue: Cortico-Striatal Circuitry and Effort–Reward Imbalance

Abstract

Recently, there has been renewed interest in the study of cognitive fatigue. It is known that fatigue is one of the most disabling symptoms in numerous neurological populations, including stroke, multiple sclerosis, Parkinson’s disease, and traumatic brain injury. Behavioral studies of cognitive fatigue are hampered by lack of correlation of self-report measures with objective performance. Neuroimaging studies provide new insight about cognitive fatigue and its neural correlates.Impairment within the cortico-striatal network, involved in effort–reward calculation, has been suggested to be critically related to fatigue. The current review surveys the recent neuroimaging literature, and suggests promising avenues for future research.

Atypical within-session motor procedural learning after traumatic brain injury but well-preserved between-session procedural memory consolidation

“…Damage to cortico-striatal pathways is a frequent finding after TBI. Cognitive fatigue might arise due to the failure of non-motor functions of the corticostriatal system such as effort-reward processing (Dobryakova et al, 2013) and reward guided behavior (Chaudhuri and Behan, 2000;Boksem and Tops, 2008). Cognitive fatigue has also been related to reductions in goal directed attention, leading even in healthy subjects to performance in a stimulus driven fashion (Boksem et al, 2005).…”

“…In a follow-up study we have conducted, increased levels of attention impairment were correlated with reduced improvements on the FOS task in participants with TBI (Stern et al, personal communication). Thus, given deficiencies in reward guided behavior and attentional capacity, practice on a daily basis may be too intensive for patients recovering from TBI, in line with the theories of cognitive fatigue (Dobryakova et al, 2013;Johansson et al, 2014). Taxing limited executive and attention capacities may lead to a reduced ability to gain from the training experience (Mathias and Wheaton, 2007).…”

“…Often patients can comply only with less intensive training sessions. Individuals after a TBI, suffer from severe fatigue or mental exhaustion that interferes with activities of daily living (Dobryakova et al, 2013;Johansson et al, 2014), and pilot studies suggested that standard FOS training protocols need to be slowed and shortened for patients after TBI. Executive cognitive functions considered as a key factor in motor control and its deficits are associated with diminished muscle and proprioceptive abilities (Abd-Elfattah et al, 2015).…”

Neuroimaging as a biomarker in symptom validity and performance validity testing

“…This research spans a great number of topics and potential disorders with a distinct emphasis on frontotemporolimbic and basal ganglia neurobiology and circuitry as well as various neurotransmitter systems, especially dopaminergic (Dobryakova et al 2013;Salamone et al 2007). Using the original terminology of Rey concerning Bmotivation^simul-taneously acknowledging that any cognitive task that requires a response regardless of its simplicity will require some aspect of guided attention, how do motivational and attentional systems come together and do these systems have relevance in understanding SVT/PVT findings?…”

“…3 was that fatigue was a problem, albeit a subjective symptom. Dobryakova et al (2013) overview the critical corticostriatal circuitry that underlie cognitive fatigue, which in part, represents a network that mediates the balance between effort and reward. Combining the contributions of hypothalamic and upper brainstem regulatory systems involved in the neurobiology of fatigue (see Harrington 2012;Induruwa et al 2012), presence of fatigue has the potential of adversely affecting cognitive performance, including SVT/PVT.…”