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Limbic and frontal structures are largely implicated in panic disorder (PD). Decreased coherence imaging values, as determined by magnetoencephalography (MEG), are suggestive of decreased or inefficient communication among these structures. We have previously demonstrated that coherence source imaging (CSI) values could be similar or higher in some PD patients. The purpose of the current investigation was to replicate these finding in a larger sample. Nine strictly diagnosed PD patients and nine age-matched and sex-matched healthy controls were examined. The CSI-MEG values of 26 frontotemporal regions (FTRs) and 28 extra-frontotemporal regions (ex-FTR; Brodmann areas) were determined for each participant. MEG scans were acquired using a 151-channel whole-head biomagnetometer system. Despite the relatively small sample size, CSI values were significantly lower in a number of FTRs in PD patients. In none of the ex-FTRs (i.e. posterior regions) were there differences between panic and control groups. The above data add to the complexity of understanding the nature of the pathophysiology of PD. Our finding of decreased focal coherence imaging values may reflect decreased excitability in these areas. The preliminary finding could be interpreted as an inhibitory process guarding against the spread of activity in closer hyperexcitable areas as seen in epilepsy. The current data provide evidence for dysfunctional communication within the frontotemporal structures. The findings have implications for the understanding of the neural circuitry underlying PD.

Neuroscientific evidence points toward atypical auditory processing in individuals with autism spectrum disorders (ASD), and yet, the consequences of this for receptive language remain unclear. Using magnetoencephalography and a passive listening task, we test for cascading effects on speech sound processing. Children with ASD and age-matched control participants (8-12 years old) listened to nonce linguistic stimuli that either did or did not conform to the phonological rules that govern consonant sequences in English (e.g. legal 'vimp' vs. illegal 'vimk'). Beamformer source analysis was used to isolate evoked responses (0.1-30 Hz) to these stimuli in the left and the right auditory cortex. Right auditory responses from participants with ASD, but not control participants, showed an attenuated response to illegal sequences relative to legal sequences that emerged around 330 ms after the onset of the critical phoneme. These results suggest that phonological processing is impacted in ASD, perhaps because of cascading effects from disrupted initial acoustic processing.

Orienting to eye gaze is a vital social skill that is absent or developmentally delayed in autism spectrum disorders (ASD). Neural synchrony in the gamma frequency band is believed to be involved in perceptual and cognitive functions such as eye-gaze processing, and has been found to be abnormal in ASD. The current study used magnetoencephalography to measure neural synchrony in the gamma frequency band in neurotypicals (n=8) and individuals with ASD (n=10) while performing a directional eye-gaze processing task. Results support impaired generation of neural synchrony in the gamma frequency band during eye-gaze processing in ASD. Impaired gamma oscillatory activity in the prefrontal cortex may be associated with impairments in social cognitive functions such as eye-gaze processing in ASD.

Increased coherence imaging values, as determined by magnetoencephalography, are indicative of increased neural excitability. The purpose of this investigation was to examine coherence imaging values in patients suffering from panic disorder (PD). We also ascertained whether regions with increased coherence had higher representation in the limbic frontotemporal regions (LFTRs). The highest coherence imaging values and their locations, among 54 Brodmann areas, were determined in six PD patients and six age-matched healthy controls. Magnetoencephalography scans were acquired using 148 magnetometer channels and 32 simultaneous EEG channels. Despite the small sample size, coherence imaging values were significantly higher in PD patients. Brain regions with increased coherence were significantly more in areas typically associated with LFTRs in PD patients when compared with controls. The above data suggest that coherence values may be increased in LFTRs of patients with PD. Recent advances in epilepsy research suggest that increased coherence may reflect increased excitability in these brain regions. On the basis of the data provided here as well as in the available literature, we propose that additional research examining coherence values in LFTRs of PD patients could inform the choice of medication in this patient population, with increased coherence (i.e. increased excitability) being a biomarker for favorable responses to medications that limit excitatory transmission, such as benzodiazepines or antiseizure drugs.