EEG correlates of cognitive load in a multiple choice reaction task

Abstract

The present study aimed to examine EEG correlates of cognitive load in a task, in which multiple stimulus-response mappings have to be maintained in working memory (WM) combined with selective inhibition of irrelevant stimulus-response mappings on every trial. Twenty-four healthy younger adults had to perform choice reaction tasks differed in the number of S-R mappings and motor response requirements. Performance was lower in the high load than in the low load condition. Performance decline at higher WM loads was accompanied by an increase of EEG power in delta, theta, and beta frequency bands and by a reduction in alpha band. The effect on alpha was generalized across all the electrodes. Correlations between EEG and performance were observed in the high load condition but not in the low load condition. Theta activity negatively correlated with reaction time, whereas positive correlations between beta activity and reaction time were found. The two frequency bands negatively correlated with each other at all electrodes. The results suggest that changes in alpha and theta power may be considered as the most sensitive indicators of cognitive load. The alpha reduction may be related to activation of widespread cortical areas which were recruited for performance of complex WM tasks. The beta increase, especially in the beta-2 range, may partly be associated with activation of motor cortex due to difficulties in preparation and execution of motor responses. Theta increases may be considered as an index of facilitation of information processing in WM and improvements in higher-order executive control, which in turn facilitates motor processes.

Effects of Neurofeedback in the Working Memory of Children with Learning Disorders: An EEG Power-Spectrum Analysis

“…With this additional comparison between the groups, the changes observed in delta and theta for the Sham group disappeared among the groups; and for the NFB group, it was now highlighted a gamma power increase at the posterior areas and a beta power decrease at the right hemisphere, compared to the Sham group. The gamma activity has been attributed to a role of memory maintenance and the binding of memory representations [39,40], and frontal and central beta activity has been related to the preparation of motor responses [27]. Given the lack of finesse of our experimental paradigm to detect the binding of memory representations, and the fact that our power spectrum analysis was performed over EEG segments taken in the maintenance phase, we assume that the increased gamma power of the NFB group reveals improved memory maintenance due to the NFB treatment, a finding that could also be an EEG substrate of the improved speed of WM retrieval for this same group of children.…”

“…Children with LD group showed a slower overall activity with more delta and theta power, and less gamma power at posterior brain sites; patterns of activity considered as indices of inefficient neural resource management to achieve proper cognitive performance. In EEG studies during cognitive tasks, the delta activity has been implied with states of sustained concentration coupled with the inhibition of sensory information [25,[27][28][29]. Higher task-related theta power is more pronounced in less apt individuals, at greater task difficulties including conditions that require a higher WM load with more items to memorize, and in situations in which the focusing of attention involves more effort [30][31][32][33][34][35]; hence, the task-related theta power is considered to be increasingly recruited according to the neural resources needed to properly perform a cognitive task.…”

Multimodal measurement approach to identify individuals with mild cognitive impairment: study protocol for a cross-sectional trial

“…The brain mapping can be helpful to identify activated structures of the cortex during task execution. 47 48 …”

Effects of Neurofeedback on the Working Memory of Children with Learning Disorders—An EEG Power-Spectrum Analysis

“…Children with LDs showed lower overall activity with more delta and theta power, and less gamma power at posterior brain sites, which is a pattern of activity considered indicative of inefficient neural resource management to achieve proper cognitive performance. In EEG studies during cognitive tasks, the delta activity has been implied with states of sustained concentration coupled with the inhibition of sensory information [ 26 , 28 , 29 , 30 ]. Higher task-related theta power is more pronounced in less apt individuals when performing more difficult tasks including situations that require a higher WM load and when focusing involves more effort [ 31 , 32 , 33 , 34 , 35 , 36 ]; hence, the task-related theta power is considered to be increasingly recruited according to the neural resources needed to properly perform a cognitive task.…”