Oscillatory responses to reward processing in borderline personality disorder

<p><i>Objectives.</i> Previous electrophysiological studies have confirmed impaired reward processing in patients with BPD. However, it is not clear which aspects of reward processing are affected and which brain regions are involved. The present study investigated both evoked and induced event-related oscillations (EROs) to feedback events (thought to represent different aspects of feedback processing), and used source localization (sLORETA) to assess activity in two areas known to contribute to reward processing, the dorsomedial prefrontal/anterior cingulate cortex (dmPFC/ACC) and the orbitofrontal cortex (OFC). <i>Methods.</i> Eighteen patients with BPD and 22 healthy controls performed a gambling task, while 64-channel electroencephalographic activity was recorded. Evoked and induced theta and high-beta band EROs as well as activity in the two regions of interest were investigated depending on the valence and magnitude of feedback events. <i>Results.</i> Theta-band responses to negative feedback were reduced in BPD, an effect that involved only evoked responses and the dmPFC/ ACC region, and was associated with trait impulsivity in patients. sLORETA analyses revealed disturbed evoked responses depending on feedback magnitude in the theta (OFC) and high-beta (dmPFC/ACC and OFC) frequency range. <i>Conclusions.</i> The results indicate multiple dysfunctions of feedback processing in patients with BPD, implicating several distinct subsets of reward-processing mechanisms.</p

Reduced auditory evoked gamma band response and cognitive processing deficits in first episode schizophrenia

<div><p></p><p><i>Objectives.</i> Gamma-band oscillations (e.g., the early auditory evoked gamma-band response, aeGBR) have been suggested to mediate cognitive and perceptual processes by driving the synchronization of local neuronal populations. Reduced aeGBR is a consistent finding in patients with schizophrenia and high-risk subjects, and has been proposed to represent an endophenotype for the illness. However, it is still unclear whether this reduction represents a deficit in sensory or cognitive processes, or a combination of the two. The present study investigated this question by manipulating the difficulty of an auditory reaction task in patients with first-episode schizophrenia and healthy controls. <i>Methods.</i> A 64-channel EEG was recorded in 23 patients with first-episode schizophrenia and 22 healthy controls during two conditions of an auditory reaction task: an easy condition that merely required low-level vigilance, and a difficult condition that placed significant demands on attention and working memory. <i>Results</i>. In contrast to healthy controls, patients failed to increase aeGBR power and phase-locking in the difficult condition. In patients, aeGBR power and phase-locking indices were associated with working memory deficits. <i>Conclusions</i>. The observed results confirm the applicability of aeGBR disturbances as a stable endophenotype of schizophrenia, and suggest a cognitive, rather than sensory, deficit at their origin.</p></div

Feedback related negativity.

<p>Grand average waveforms of feedback-related visual evoked potentials for the maximum loss (red), maximum gain (black), minimum loss (green) and minimum gain (blue) condition showing the FRN effect with larger FRN amplitudes in response to loss feedback compared to gain feedback (onset of feedback stimuli at 0 ms). The scalp topography (derived from the peak amplitude of the difference waveform of maximum loss and maximum gain condition observed 270 ms after presentation of the feedback stimulus) shows a frontocentral maximum over Fz.</p

Time frequency analysis.

<p>The comparison (difference) of the results of the time-frequency analysis of maximum loss and maximum gain conditions revealed theta, alpha and low-beta activity to be more pronounced in the maximum loss condition and delta and high-beta activity to be more pronounced in the maximum gain condition (onset of feedback stimuli at 0 ms). For all frequencies, we found frontocentral maxima of differences between conditions. The scalp topographies are derived from the peak amplitudes of the difference waveforms (maximum loss minus maximum gain condition) of the extracted frequency-specific wavelet layers (latencies: delta 150 ms; theta 340 ms; alpha 550 ms; low-beta 630 ms; high-beta 360 ms). The dotted lines indicate the frequencies of interest (from the bottom up: delta, theta, alpha, low-beta and high-beta).</p

Characteristics of the participant group.

<p>Characteristics of the participant group.</p

Paradigm.

<p>Schematic diagram showing the design of a trial of the gambling task used in this study.</p

Mean values of electrophysiological measures per condition and ANOVA results.

<p>Amplitudes are reported in µV; latencies are reported in milliseconds. n.s.  =  not significant.</p

Plasma and serum brain-derived neurotrophic factor (BDNF) levels and their association with neurocognition in at-risk mental state, first episode psychosis and chronic schizophrenia patients

<p><b>Objectives:</b> Brain-derived neurotrophic factor (BDNF) is involved in numerous cognitive processes. Since cognitive deficits are a core feature of psychotic disorders, the investigation of BDNF levels in psychosis and their correlation with cognition has received increased attention. However, there are no studies investigating BDNF levels in individuals with an at-risk mental state (ARMS) for psychosis. Hence, the aims of the present study were: (1) assessing peripheral BDNF levels across different (potential) stages of psychosis; (2) investigating their association with cognition.</p> <p><b>Methods:</b> Plasma and serum BDNF levels and neuropsychological performance were assessed in 16 ARMS, six first-episode psychosis (FEP), and 11 chronic schizophrenia (CS) patients. Neuropsychological assessment covered intelligence, verbal memory, working memory, attention and executive functioning.</p> <p><b>Results:</b> Both plasma and serum BDNF levels were highest in CS, intermediate in FEP and lowest in ARMS. Multiple regression analysis revealed a significant positive association of plasma BDNF levels with planning ability across all groups.</p> <p><b>Conclusions:</b> The lower peripheral BDNF levels in ARMS compared to FEP and CS might point towards an important drop of this neurotrophin prior to the onset of frank psychosis. The associations of peripheral BDNF with planning-abilities match previous findings.</p

Growth curve.

<p>Verbal learning performances of at-risk mental state (ARMS) patients with (ARMS-T) and without later transition to psychosis (ARMS-NT) and first episode psychosis (FEP) patients. Lines per group correspond to the mean of total words remembered per trial.</p

Visualisation of the confirmatory four factor analysis (CFA).

<p>The rectangles on the left represent the patient groups (at-risk mental state (ARMS) patients with (ARMS-T) and without later transition to psychosis (ARMS-NT) and first episode psychosis (FEP) patients). The circles in the middle represent the latent variables, which are measured by the indicator variables. The rectangles on the right represent the indicator variables, which consist out of observable data. Pathways are represented by arrows, showing the standardized XY estimates for each path. ¹ Non standardized dispersion.</p