Impaired task-switching in major depressive disorder: A time-frequency analysis of non-emotional and emotional...

Major depressive disorder (MDD) is characterized by significant impairments in cognitive functions, including task-switching dysfunction. This study investigates the differences in switching impairments between non-emotional and emotional switching tasks in MDD patients and explores the underlying neuropsychological mechanisms.

48 MDD patients and 52 healthy controls (HCs) were recruited. Behavioral and electroencephalogram data were recorded while participants performed non-emotional and emotional task-switching paradigms. Event-related potentials (ERPs: P2, N2, P3 difference waves) and event-related spectral perturbations (ERSPs: theta, alpha, beta band power) were analyzed to assess group differences.

In the magnitude task, MDD group displayed reduced occipital Pd2 amplitude (p < 0.001, η²_p=0.20), increased frontal/central Pd3 amplitudes (p < 0.001, η²_p=0.10), and larger alpha power differences (p < 0.05, η²_p= 0.04). In the gender task, MDD group had increased occipital Pd2 amplitude (p < 0.05, η²_p=0.04) and larger alpha power differences in the P3 time window (p < 0.01, η²_p=0.03). In the emotion task, MDD group showed prolonged Pd2 latency (p < 0.05, η²_p=0.04), reduced Pd3 amplitude (p < 0.05, η²_p=0.10), smaller theta power differences (p = 0.05, η²_p=0.03), and larger beta power differences (p < 0.05, η²_p=0.04).

MDD patients exhibit a dissociable pattern of task-switching deficits across non-emotional and emotional task-switching scenarios, characterized by distinct abnormalities across early visual processing, conflict monitoring, cognitive resource allocation, and multi-stage emotional processing. This study reveals novel electrophysiological mechanisms underlying cognitive inflexibility in MDD.