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EEG findings of reduced neural synchronization during visual integration in schizophrenia.

Wynn JK, Roach BJ, Lee J, Horan WP, Ford JM, Jimenez AM, Green MF - PLoS ONE (2015)

Bottom Line: Compared to controls, patients failed to show increased phase locking to illusory versus no contours between 40-60 Hz.These results suggest that the pattern of results across visual processing conditions is similar in patients and controls.However, patients have deficits in neural synchronization in the gamma range during basic processing of illusory contours when attentional demand is limited.

View Article: PubMed Central - PubMed

Affiliation: Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States of America; Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, United States of America.

ABSTRACT
Schizophrenia patients exhibit well-documented visual processing deficits. One area of disruption is visual integration, the ability to form global objects from local elements. However, most studies of visual integration in schizophrenia have been conducted in the context of an active attention task, which may influence the findings. In this study we examined visual integration using electroencephalography (EEG) in a passive task to elucidate neural mechanisms associated with poor visual integration. Forty-six schizophrenia patients and 30 healthy controls had EEG recorded while passively viewing figures comprised of real, illusory, or no contours. We examined visual P100, N100, and P200 event-related potential (ERP) components, as well as neural synchronization in the gamma (30-60 Hz) band assessed by the EEG phase locking factor (PLF). The N100 was significantly larger to illusory vs. no contour, and illusory vs. real contour stimuli while the P200 was larger only to real vs. illusory stimuli; there were no significant interactions with group. Compared to controls, patients failed to show increased phase locking to illusory versus no contours between 40-60 Hz. Also, controls, but not patients, had larger PLF between 30-40 Hz when viewing real vs. illusory contours. Finally, the positive symptom factor of the BPRS was negatively correlated with PLF values between 40-60 Hz to illusory stimuli, and with PLF between 30-40 Hz to real contour stimuli. These results suggest that the pattern of results across visual processing conditions is similar in patients and controls. However, patients have deficits in neural synchronization in the gamma range during basic processing of illusory contours when attentional demand is limited.

No MeSH data available.


Related in: MedlinePlus

Time-frequency plots of phase locking factor for controls (top) and patients (bottom) for all three figure types.Plots from four representative electrodes (PO3, PO4, PO7, PO8) are shown. The scale for each plot is included. Frequency is plotted on the y-axis and ranges from 25–70 Hz (from top to bottom); time from onset of the stimulus is plotted on the x-axis and ranges from-100 to 500 ms. The blue box highlights the 30–40 Hz band and the red box the 40–60 Hz band that were analyzed.
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pone.0119849.g004: Time-frequency plots of phase locking factor for controls (top) and patients (bottom) for all three figure types.Plots from four representative electrodes (PO3, PO4, PO7, PO8) are shown. The scale for each plot is included. Frequency is plotted on the y-axis and ranges from 25–70 Hz (from top to bottom); time from onset of the stimulus is plotted on the x-axis and ranges from-100 to 500 ms. The blue box highlights the 30–40 Hz band and the red box the 40–60 Hz band that were analyzed.

Mentions: Time-frequency plots of phase locking at representative electrodes PO3, PO4, PO7, and PO8 are shown in Fig. 4. We examined mean PLF (across all electrodes) separately within the 30–40 Hz and 40–60 Hz frequency band between 70–100 ms, and these values are shown in Table 3. For the 30–40 Hz band, there was a significant main effect of group, F1, 74 = 4.15, p < 0.05, ƞp2 = 0.05. Patients had significantly lower PLF compared to controls, 0.11 (0.02) vs. 0.13 (0.07), respectively. The main effect of figure type and the figure type x group interaction were not significant.


EEG findings of reduced neural synchronization during visual integration in schizophrenia.

Wynn JK, Roach BJ, Lee J, Horan WP, Ford JM, Jimenez AM, Green MF - PLoS ONE (2015)

Time-frequency plots of phase locking factor for controls (top) and patients (bottom) for all three figure types.Plots from four representative electrodes (PO3, PO4, PO7, PO8) are shown. The scale for each plot is included. Frequency is plotted on the y-axis and ranges from 25–70 Hz (from top to bottom); time from onset of the stimulus is plotted on the x-axis and ranges from-100 to 500 ms. The blue box highlights the 30–40 Hz band and the red box the 40–60 Hz band that were analyzed.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4364708&req=5

pone.0119849.g004: Time-frequency plots of phase locking factor for controls (top) and patients (bottom) for all three figure types.Plots from four representative electrodes (PO3, PO4, PO7, PO8) are shown. The scale for each plot is included. Frequency is plotted on the y-axis and ranges from 25–70 Hz (from top to bottom); time from onset of the stimulus is plotted on the x-axis and ranges from-100 to 500 ms. The blue box highlights the 30–40 Hz band and the red box the 40–60 Hz band that were analyzed.
Mentions: Time-frequency plots of phase locking at representative electrodes PO3, PO4, PO7, and PO8 are shown in Fig. 4. We examined mean PLF (across all electrodes) separately within the 30–40 Hz and 40–60 Hz frequency band between 70–100 ms, and these values are shown in Table 3. For the 30–40 Hz band, there was a significant main effect of group, F1, 74 = 4.15, p < 0.05, ƞp2 = 0.05. Patients had significantly lower PLF compared to controls, 0.11 (0.02) vs. 0.13 (0.07), respectively. The main effect of figure type and the figure type x group interaction were not significant.

Bottom Line: Compared to controls, patients failed to show increased phase locking to illusory versus no contours between 40-60 Hz.These results suggest that the pattern of results across visual processing conditions is similar in patients and controls.However, patients have deficits in neural synchronization in the gamma range during basic processing of illusory contours when attentional demand is limited.

View Article: PubMed Central - PubMed

Affiliation: Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States of America; Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, United States of America.

ABSTRACT
Schizophrenia patients exhibit well-documented visual processing deficits. One area of disruption is visual integration, the ability to form global objects from local elements. However, most studies of visual integration in schizophrenia have been conducted in the context of an active attention task, which may influence the findings. In this study we examined visual integration using electroencephalography (EEG) in a passive task to elucidate neural mechanisms associated with poor visual integration. Forty-six schizophrenia patients and 30 healthy controls had EEG recorded while passively viewing figures comprised of real, illusory, or no contours. We examined visual P100, N100, and P200 event-related potential (ERP) components, as well as neural synchronization in the gamma (30-60 Hz) band assessed by the EEG phase locking factor (PLF). The N100 was significantly larger to illusory vs. no contour, and illusory vs. real contour stimuli while the P200 was larger only to real vs. illusory stimuli; there were no significant interactions with group. Compared to controls, patients failed to show increased phase locking to illusory versus no contours between 40-60 Hz. Also, controls, but not patients, had larger PLF between 30-40 Hz when viewing real vs. illusory contours. Finally, the positive symptom factor of the BPRS was negatively correlated with PLF values between 40-60 Hz to illusory stimuli, and with PLF between 30-40 Hz to real contour stimuli. These results suggest that the pattern of results across visual processing conditions is similar in patients and controls. However, patients have deficits in neural synchronization in the gamma range during basic processing of illusory contours when attentional demand is limited.

No MeSH data available.


Related in: MedlinePlus