Reduced Sensitivity to Non-Fear-Related Stimulus Changes in Panic Disorder

Anxiety attenuates learning advantages conferred by statistical stability and induces loss of volatility-attuning in brain activity

Anxiety can alter an individual's perception of their external sensory environment. Previous studies suggest that anxiety can increase the magnitude of neural responses to unexpected (or surprising) stimuli. Additionally, surprise responses are reported to be boosted during stable compared to volatile environments. Few studies, however, have examined how learning is impacted by both threat and volatility. To investigate these effects, we used threat-of-shock to transiently increase subjective anxiety in healthy adults while they performed an auditory oddball task under stable and volatile environments and while undergoing functional Magnetic Resonance Imaging (fMRI) scanning. We then used Bayesian Model Selection (BMS) mapping to identify the brain areas where different models of anxiety displayed the highest evidence. Behaviourally, we found that threat-of-shock eliminated the accuracy advantage conferred by environmental stability over volatility. Neurally, we found that threat-of-shock led to attenuation and loss of volatility-attuning of brain activity evoked by surprising sounds across most subcortical and limbic regions including the thalamus, basal ganglia, claustrum, insula, anterior cingulate, hippocampal gyrus and the superior temporal gyrus. Taken together, our findings suggest that threat eliminates learning advantages conferred by statistical stability compared to volatility. Thus, we propose that anxiety disrupts behavioural adaptation to environmental statistics, and that multiple subcortical and limbic regions are implicated in this process.

Tackling hypo and hyper sensory processing heterogeneity in autism: From clinical stratification to genetic pathways

As an integral part of autism spectrum symptoms, sensory processing issues including both hypo and hyper sensory sensitivities. These sensory specificities may result from an excitation/inhibition imbalance with a poorly understood of their level of convergence with genetic alterations in GABA-ergic and glutamatergic pathways. In our study, we aimed to characterize the hypo/hyper-sensory profile among autistic individuals. We then explored its link with the burden of deleterious mutations in a subset of individuals with available whole-genome sequencing data. To characterize the hypo/hyper-sensory profile, the differential Short Sensory Profile (dSSP) was defined as a normalized and centralized hypo/hypersensitivity ratio from the Short Sensory Profile (SSP). Including 1136 participants (533 autistic individuals, 210 first-degree relatives, and 267 controls) from two independent study samples (PARIS and LEAP), we observed a statistically significant dSSP mean difference between autistic individuals and controls, driven mostly by a high dSSP variability, with an intermediated profile represented by relatives. Our genetic analysis tended to associate the dSSP and the hyposensitivity with mutations of the GABAergic pathway. The major limitation was the dSSP difficulty to discriminate subjects with a similar quantum of hypo- and hyper-sensory symptoms to those with no such symptoms, resulting both in a similar ratio score of 0. However, the dSSP could be a relevant clinical score, and combined with additional sensory descriptions, genetics and endophenotypic substrates, will improve the exploration of the underlying neurobiological mechanisms of sensory processing differences in autism spectrum.

Mutually exclusive disorder-dependent hearing discomfort in first-episode psychosis and panic disorder: two experiments using the same auditory stimulus set and two similar musical sequences

We investigated the level of hearing tolerance in patients with first-episode psychosis (FEP) and panic disorder (PD) as compared to two different groups of healthy controls (HC, HC2), one for each experiment, because we used two distinct psychophysical paradigms. We evaluated auditory discomfort of 28 volunteers (14 with FEP and 14 HC) in the first study and of 42 volunteers (21 with PD and 21 HC2) in the second study. We presented 20 sounds: 16 pure-tone frequency sweeps (specially designed for use with FEP) and 11 s or 13 s musical sequences from the very beginning of the music "Play the Game" (PLAY) from Queen and its reverses. The first procedure used a Likert-like 0-10 scale ranging from "nothing bad" to "too bad" where volunteers made vertical marks along a horizontal line according to their discomfort. The second procedure involved subjective magnitude estimation online due to the SARS-COV-19 pandemic. Sounds were placed online and played by PD and HC2 volunteers themselves after having listened to the standard (the first 8 s from RADIO, "Radio Ga Ga" by Queen). Then, PD and HC2 volunteers were asked to assign values equal to, or multiples of 10 that felt like, or proportional to, their hearing "discomfort" in comparison with Sound 00 (RADIO). Our findings showed that FEP volunteers assign more discomfort to the 16 specially designed frequency sweep stimuli that appear not to affect HC, HC2, and PD. On the other hand, musical sequences from PLAY caused strong discomfort to PD in the reverse mode, but did not seem to affect HC, HC2, and FEP. Further experiments using the exact same paradigm with FEP and PD are needed to explore these findings.

Dysfunctional frontal activation of mismatch negativity in panic disorder: A magnetoencephalographic study

BACKGROUND

Mismatch negativity (MMN) or its magnetic counterpart (MMNm) is a neurophysiological signal to reflect the automatic change-detection ability. However, MMN studies in patients with panic disorder (PD) showed contrasting results using electroencephalographic (EEG) recordings. The present study attempted to overcome the limitations of EEG methodology by means of a whole-head magnetoencephalography (MEG) combined with the depth-weighted minimum norm estimate method to conduct an in-depth investigation on the MMNm at the cortical level in patients with PD.

METHODS

We recruited 22 healthy controls (HC) and 20 patients with PD to perform auditory oddball paradigm during MEG recordings. The cortical MMNm amplitudes and latencies in the superior temporal gyrus, inferior parietal lobule, and inferior frontal gyrus (IFG) were compared between the HC and PD groups. The correlations between MMNm responses and clinical measurement were also examined.

RESULTS

Compared with the HC group, the PD group demonstrated significantly reduced MMNm amplitudes in the IFG. Furthermore, higher trait scores of the State-Trait Anxiety Inventory were associated with lower MMNm amplitudes of the right IFG among patients with PD.

LIMITATIONS

Generalization of the current results to other settings or samples should be made cautiously due to the use of different medication regimens and presence of comorbidities in our patients.

CONCLUSIONS

Our data suggest dysfunctional pre-attentive change-detection ability in patients with PD, particularly in the IFG.

P50, N100, and P200 Sensory Gating in Panic Disorder

Panic disorder (PD) has been linked to abnormalities in information processing. However, only little evidence has been published for sensory gating in PD. Sensory gating describes the brain's ability to exclude stimuli of low relevance from higher level information processing, thereby sustaining efficient cognitive processing. Deficits in sensory gating have been associated with various psychiatric conditions, most prominently schizophrenia. In this case-control event-related potential study, we tested 32 patients with PD and 39 healthy controls in a double click paradigm. Both groups were compared with regard to pre-attentive (P50), early-attentive (N100), and late-attentive (P200) sensory gating indices. Contrary to a hypothesized deficit, PD patients and healthy controls showed no differences in P50, N100 and P200 values. These results suggest that sensory gating seems to be functional across the pre-attentive, early-attentive, and late-attentive time span in this clinical population. Given this consistency across auditory sensory gating indices, further research aiming to clarify information processing deficits in PD should focus on other neurophysiological markers to investigate information processing deficits in PD (eg, P300, error-related negativity or mismatch negativity).