From basic perception deficits to facial affect recognition impairments in schizophrenia

Abstract

While impaired facial emotion recognition and magnocellular deficits in visual perception are core features of schizophrenia, their relationship is still unclear. Our aim was to analyze the oscillatory background of these processes and to investigate the connection between the magnocellular pathway deficit and the abnormal facial affect processing. Thirty-nine subjects with schizophrenia and forty socially matched healthy controls subjects were enrolled. A 128 channel EEG was recorded in three experimental tasks: first, participants viewed magnocellular biased low-spatial frequency (LSF) and parvocellular biased high-spatial frequency (HSF) Gabor-patches, then faces and houses were presented and in the third task a facial affect recognition task was presented with happy, sad and neutral faces. Event-related theta (4-7 Hz) synchronization (ERS) (i.e. an increase in theta power) by magnocellular biased stimuli was decreased in patients relative to controls, while no similar differences were found between groups in the parvocellular biased condition. ERS was significantly lower in patients compared to healthy controls both in the face and in the emotion recognition task. Theta ERS to magnocellular biased stimuli, but not to parvocellular biased stimuli, were correlated with emotion recognition performance. These findings indicate a bottom up disruption of face perception and emotion recognition in schizophrenia.

Figure 1

Schematic illustration of the experimental paradigms. (a) Visual stimuli paradigm: 224 low-spatial frequency Gabor-patches (p = 0.45), 224 high-spatial frequency Gabor-patches (p = 0.45) and 50 faces (p = 0.1) were presented for 100 ms, the stimulus onset asynchronies were randomized between 850–900 ms. Subjects had to identified faces by button press. (b) Face/non-face paradigm: 80 faces (p = 0.5) and 80 houses (p = 0.5) were presented for 100 ms with randomized stimulus onset asynchronies between 2000–2500 ms. The subject had to response by a button press whether they see a face or a house. (c) Emotion recognition paradigm: 80 sad (p = 33.3), 80 neutral (p = 33.3) and 80 happy (p = 33.3) faces were presented (from: Karolisnka Directed Emotional Face set: http://www.emotionlab.se/resources/kdef), each for 100 ms, the stimulus onset asynchronies were randomized between 2000–2500 ms. Subjects had to identified emotions by button press.

Figure 2

The map of 128 + 2 electrodes and the 5 regions of interest (ROIs): a frontal, a central, a mid-occipital, right parieto-occipital and left parieto-occipital regions. Electrode clusters selected for analyses (Regions of Interests) are marked with black dots in the scalp map.

Figure 3

(a) Scalp topography of the theta event-related spectral perturbation (ERSP) in the 140–280 ms (LSF) and in the 100–200 ms (HSF) time windows and (b) theta ERSP to the low-spatial frequency (LSF) and high-spatial frequency (HSF) conditions in the two study groups (blue = Healthy control participants, red = Subjects with schizophrenia).

Figure 4

Mean theta ERSP in high-spatial frequency-HSF (time window: 100–200 ms) and low-spatial frequency-LSF (time window: 140–280 ms) conditions in the two study groups. (blue = Heathy control participants, red = Subjects with schizophrenia, box = interquartile range (IQR), dots = measurements on single subjects, error bars = maximum and minimum observation inside the 1.5 IQR, line in the box = median, circle = mean).

Figure 5

(a) Scalp topography of the theta event-related spectral perturbation (ERSP) in the 140–240 ms time windows and (b) theta ERSP to face and non-face conditions in the two study groups (blue = Healthy control participants, red = Subjects with schizophrenia).

Figure 6

(a) Scalp topography of the theta event-related spectral perturbation (ERSP) in the 140–200 ms time window and (b) theta ERSP to the three experimental conditions in the two study groups (blue = Healthy control participants, red = Subjects with schizophrenia).