Aperiodic and oscillatory neural activity underlying external and internal attention

Area of Science:

• Neuroscience
• Cognitive Science
• Electrophysiology

Background:

• Attention research primarily focuses on external attention, neglecting internal attention.
• Existing electroencephalography (EEG) studies often use composite measures, failing to distinguish oscillatory and aperiodic brain activity.
• Direct comparisons between internal and external attentional states are scarce.

Purpose of the Study:

• To investigate if internal and external attention differentially modulate the aperiodic component of EEG signals.
• To explore the relationship between aperiodic EEG activity and oscillatory measures (alpha, beta) during attention.
• To determine the functional significance of aperiodic EEG features in different attentional states.

Main Methods:

• Recorded EEG data from participants performing an attention task.
• Instructed participants to switch between attending externally (to tones) and internally (to thoughts).
• Analyzed both oscillatory and aperiodic components of the EEG signal.

Main Results:

• Internal attention was associated with a smaller aperiodic offset and a flatter slope (exponent) compared to external attention.
• The interplay between aperiodic parameters and alpha/beta oscillations differed between internal and external attention.
• Aperiodic EEG features predicted task accuracy in the external condition, while alpha oscillations predicted attention ratings in the internal condition.

Conclusions:

• Internal and external attention states exhibit distinct electrophysiological signatures in EEG.
• The aperiodic component of EEG signals plays a differential functional role in internal versus external attention.
• Differentiating aperiodic and oscillatory activity provides deeper insights into the neural basis of attention.