Auditory Cortex Thickness Is Associated With N100 Amplitude in Schizophrenia Spectrum Disorders

The auditory cortex (AC) may play a central role in the pathophysiology of schizophrenia and auditory hallucinations (AH). Previous schizophrenia studies report thinner AC and impaired AC function, as indicated by decreased N100 amplitude of the auditory evoked potential. However, whether these structural and functional alterations link to AH in schizophrenia remain poorly understood.

Patients with a schizophrenia spectrum disorder (SCZ_spect), including patients with a lifetime experience of AH (AH+), without (AH-), and healthy controls underwent magnetic resonance imaging (39 SCZ_spect, 22 AH+, 17 AH-, and 146 HC) and electroencephalography (33 SCZ_spect, 17 AH+, 16 AH-, and 144 HC). Cortical thickness of the primary (AC1, Heschl's gyrus) and secondary (AC2, Heschl's sulcus, and the planum temporale) AC was compared between SCZ_spect and controls and between AH+, AH-, and controls. To examine if the association between AC thickness and N100 amplitude differed between groups, we used regression models with interaction terms.

N100 amplitude was nominally smaller in SCZ_spect (P = .03, d = 0.42) and in AH- (P = .020, d = 0.61), while AC2 was nominally thinner in AH+ (P = .02, d = 0.53) compared with controls. AC1 thickness was positively associated with N100 amplitude in SCZ_spect (t = 2.56, P = .016) and AH- (t = 3.18, P = .008), while AC2 thickness was positively associated with N100 amplitude in SCZ_spect (t = 2.37, P = .024) and in AH+ (t = 2.68, P = .019).

The novel findings of positive associations between AC thickness and N100 amplitude in SCZ_spect, suggest that a common neural substrate may underlie AC thickness and N100 amplitude alterations.