Childhood trauma predicts blunted error monitoring in adulthood: An event-related potential study.

Abuse and neglect have detrimental consequences on emotional and cognitive functioning during childhood and adolescence, including error monitoring, which is a critical aspect of cognition that has been implicated in certain internalizing and externalizing psychopathologies. It is unclear, however, whether (a) childhood trauma has effects on error monitoring and, furthermore whether, (b) error monitoring mediates the relation between childhood trauma and psychopathology in adulthood. To this end, in a large sample of young adults (ages 18-30) who were oversampled for psychopathology (N = 390), the present study assessed relations between childhood trauma and error-related negativity (ERN), which is a widely used neurophysiological indicator of error monitoring. Cumulative childhood trauma predicted ERN blunting, as did two specific types of traumas: sexual abuse and emotional neglect. Furthermore, the ERN partially mediated the effects of cumulative childhood trauma and emotional neglect on externalizing-related symptoms. Future studies should further examine the relations between childhood trauma and error monitoring in adulthood, which can help to inform intervention approaches.

Examining the Construct Validity of Borderline Personality Traits Using Familial Aggregation and Other External Validators.

Numerous studies have questioned the reliability and validity of borderline personality disorder's (BPD) categorical conceptualization. DSM-5 Section III's alternative trait-based model of BPD may better capture borderline pathology, but aspects of its validity should be further established. Thus, the authors examined whether a latent BPD factor derived from Section III traits exhibits (1) familial aggregation among siblings and (2) association with constructs related to borderline pathology. The authors also tested whether gender moderated associations. A total of 498 community-recruited adults completed the Personality Inventory for DSM-5, a behavioral assessment of risk-taking, and reported their history of childhood maltreatment, substance use, nonsuicidal self-injury, and suicidal ideation. Familial aggregation was assessed among 232 sibling pairs. Siblings' BPD scores were significantly correlated and most external validators were significantly associated with BPD, with the exception of risk-taking. Results did not vary by gender. Findings further support the construct validity of Section III's BPD trait profile.

Delayed extinction fails to reduce skin conductance reactivity to fear-conditioned stimuli.

A brief 10-min time delay between an initial and subsequent exposure to extinction trials has been found to impair memory reconsolidation in fear-conditioned rodents and humans, providing a potential means to reduce fearfulness in anxiety disorders and posttraumatic stress disorder (PTSD). The present study used videos of biologically prepared, conditioned stimuli (tarantulas) to test the efficacy of delayed extinction in blocking reconsolidation of conditioned fear in healthy young adults. Strong differential conditioning, measured by skin conductance, was observed among a screened subset of participants during acquisition. However, the delayed-extinction intervention failed to reduce reactivity to the conditioned stimulus paired with the extinction delay. These results are partially consistent with other recent, mixed findings and point to a need for testing other candidate interventions designed to interfere with the reconsolidation process.

Pilot Study of Neurological Soft Signs and Depressive and Postconcussive Symptoms During Recovery From Mild Traumatic Brain Injury (mTBI).

Neurological soft signs (NSSs) tap into a variety of perceptual, motor, and cognitive functions. The authors administered a battery of NSSs serially to a group of 14 pilot patients recruited from an emergency room after they experienced a mild traumatic brain injury. Patients were seen within 96 hours after injury, and again 30 and 90 days later. Measures of balance, mood, and postconcussive symptoms and impairment were also obtained. NSSs and balance improved across visits. Across visits, NSSs and balance were not significantly associated with any postconcussive outcome measures, although depressive symptoms were. Initial neurological impairment appeared to predict subsequent residual postconcussive symptoms and impairment, but this result requires replication.

Pharmacological blockade of memory reconsolidation in posttraumatic stress disorder: three negative psychophysiological studies.

Posttraumatic stress disorder (PTSD) may involve over-consolidated emotional memories of the traumatic event. Reactivation (RP) can return a memory to an unstable state, from which it must be restabilized (reconsolidated) if it is to persist. Pharmacological agents administered while the memory is unstable have been shown to impair reconsolidation. The N-methyl-d-aspartate (NMDA) partial agonist d-cycloserine (DCS) may promote memory destabilization. In the three studies reported here, we investigated whether the ß-adrenergic blocker propranolol or the glucocorticoid (GR) antagonist mifepristone, given at the time of traumatic memory reactivation, could reduce PTSD symptoms and physiological responding during subsequent traumatic imagery. Individuals with PTSD were randomized as follows: Study One: propranolol with memory reactivation (n=10) or without reactivation (n=8); Study Two: reactivation mifepristone (n=13), non-reactivation (NRP) mifepristone (n=15), or double placebo (PL) (n=15); Study Three: reactivation mifepristone plus d-cycloserine (n=16), or two placebos (n=15). Subjects underwent memory retrieval by describing their traumatic event. A week later they engaged in script-driven traumatic mental imagery, while heart rate (HR), skin conductance (SC), and facial electromyogram (EMG) responses were measured. There were no significant group differences in physiological responsivity or change in PTSD symptoms in any of the studies. These results do not support successful blockade of reconsolidation of traumatic memories in PTSD.

Prereactivation propranolol fails to reduce skin conductance reactivity to prepared fear-conditioned stimuli.

Pharmacologic blockade of memory reconsolidation has been demonstrated in fear-conditioned rodents and humans and may provide a means to reduce fearfulness in anxiety disorders and posttraumatic stress disorder. Studying the efficacy of potential interventions in clinical populations is challenging, creating a need for paradigms within which candidate reconsolidation-blocking interventions can be readily tested. We used videos of biologically prepared conditioned stimuli (tarantulas) to test the efficacy of propranolol in blocking reconsolidation of conditioned fear in healthy young adults. Strong differential conditioning, measured by skin conductance, was observed among a screened subset of participants during acquisition. However, subsequent propranolol failed to reduce reactivity to the reactivated conditioned stimulus. These results are consistent with other recent findings and point to a need for testing other candidate drugs.

Strain-optic active control for quantum integrated photonics.

We present a practical method for active phase control on a photonic chip that has immediate applications in quantum photonics. Our approach uses strain-optic modification of the refractive index of individual waveguides, effected by a millimeter-scale mechanical actuator. The resulting phase change of propagating optical fields is rapid and polarization-dependent, enabling quantum applications that require active control and polarization encoding. We demonstrate strain-optic control of non-classical states of light in silica, showing the generation of 2-photon polarisation N00N states by manipulating Hong-Ou-Mandel interference. We also demonstrate switching times of a few microseconds, which are sufficient for silica-based feed-forward control of photonic quantum states.

Cortical and cerebellar modulation of autonomic responses to loud sounds.

Detecting unexpected environmental change causes modulation of autonomic activity essential for survival. Understanding the neural mechanisms associated with responses to loud sounds may provide insights into the pathophysiology of posttraumatic stress disorder (PTSD), since individuals with PTSD exhibit heightened autonomic responses to unexpected loud sounds. We combined fMRI with autonomic psychophysiological assessment to investigate central and peripheral reactivity to loud tones in 20 healthy participants. Activity in anterior insula, pregenual anterior cingulate cortex, anterior midcingulate cortex, supplementary motor area, supramarginal gyrus, and cerebellar lobules VIII-IX was associated with both tones and concomitant skin conductance responses. Since regions signaling unexpected external events modulate autonomic activity, heightened loud tone autonomic responses in PTSD may reflect sensitization of this "salience" network.

High quantum-efficiency photon-number-resolving detector for photonic on-chip information processing.

The integrated optical circuit is a promising architecture for the realization of complex quantum optical states and information networks. One element that is required for many of these applications is a high-efficiency photon detector capable of photon-number discrimination. We present an integrated photonic system in the telecom band at 1550 nm based on UV-written silica-on-silicon waveguides and modified transition-edge sensors capable of number resolution and over 40 % efficiency. Exploiting the mode transmission failure of these devices, we multiplex three detectors in series to demonstrate a combined 79 % ± 2 % detection efficiency with a single pass, and 88 % ± 3 % at the operating wavelength of an on-chip terminal reflection grating. Furthermore, our optical measurements clearly demonstrate no significant unexplained loss in this system due to scattering or reflections. This waveguide and detector design therefore allows the placement of number-resolving single-photon detectors of predictable efficiency at arbitrary locations within a photonic circuit - a capability that offers great potential for many quantum optical applications.

Linear optical quantum computing in a single spatial mode.

We present a scheme for linear optical quantum computing using time-bin-encoded qubits in a single spatial mode. We show methods for single-qubit operations and heralded controlled-phase (cphase) gates, providing a sufficient set of operations for universal quantum computing with the Knill-Laflamme-Milburn [Nature (London) 409, 46 (2001)] scheme. Our protocol is suited to currently available photonic devices and ideally allows arbitrary numbers of qubits to be encoded in the same spatial mode, demonstrating the potential for time-frequency modes to dramatically increase the quantum information capacity of fixed spatial resources. As a test of our scheme, we demonstrate the first entirely single spatial mode implementation of a two-qubit quantum gate and show its operation with an average fidelity of 0.84±0.07.

On-chip low loss heralded source of pure single photons.

A key obstacle to the experimental realization of many photonic quantum-enhanced technologies is the lack of low-loss sources of single photons in pure quantum states. We demonstrate a promising solution: generation of heralded single photons in a silica photonic chip by spontaneous four-wave mixing. A heralding efficiency of 40%, corresponding to a preparation efficiency of 80% accounting for detector performance, is achieved due to efficient coupling of the low-loss source to optical fibers. A single photon purity of 0.86 is measured from the source number statistics without narrow spectral filtering, and confirmed by direct measurement of the joint spectral intensity. We calculate that similar high-heralded-purity output can be obtained from visible to telecom spectral regions using this approach. On-chip silica sources can have immediate application in a wide range of single-photon quantum optics applications which employ silica photonics.

Neurological soft signs in individuals with pathological gambling.

Increased neurological soft signs (NSSs) have been found in a number of neuropsychiatric syndromes, including chemical addiction. The present study examined NSSs related to perceptual-motor and visuospatial processing in a behavioral addiction viz., pathological gambling (PG). As compared to mentally healthy individuals, pathological gamblers displayed significantly poorer ability to copy two- and three-dimensional figures, to recognize objects against a background noise, and to orient in space on a road-map test. Results indicated that PG is associated with subtle cerebral cortical abnormalities. Further prospective clinical research is needed to address the NSSs' origin and chronology (e.g., predate or follow the development of PG) as well as their response to therapeutic interventions and/or their ability to predict such a response.

Multiphoton quantum interference in a multiport integrated photonic device.

Increasing the complexity of quantum photonic devices is essential for many optical information processing applications to reach a regime beyond what can be classically simulated, and integrated photonics has emerged as a leading platform for achieving this. Here we demonstrate three-photon quantum operation of an integrated device containing three coupled interferometers, eight spatial modes and many classical and nonclassical interferences. This represents a critical advance over previous complexities and the first on-chip nonclassical interference with more than two photonic inputs. We introduce a new scheme to verify quantum behaviour, using classically characterised device elements and hierarchies of photon correlation functions. We accurately predict the device's quantum behaviour and show operation inconsistent with both classical and bi-separable quantum models. Such methods for verifying multiphoton quantum behaviour are vital for achieving increased circuit complexity. Our experiment paves the way for the next generation of integrated photonic quantum simulation and computing devices.

Boson sampling on a photonic chip.

Although universal quantum computers ideally solve problems such as factoring integers exponentially more efficiently than classical machines, the formidable challenges in building such devices motivate the demonstration of simpler, problem-specific algorithms that still promise a quantum speedup. We constructed a quantum boson-sampling machine (QBSM) to sample the output distribution resulting from the nonclassical interference of photons in an integrated photonic circuit, a problem thought to be exponentially hard to solve classically. Unlike universal quantum computation, boson sampling merely requires indistinguishable photons, linear state evolution, and detectors. We benchmarked our QBSM with three and four photons and analyzed sources of sampling inaccuracy. Scaling up to larger devices could offer the first definitive quantum-enhanced computation.

Brillouin gain suppression in photonic crystal fibers with random acoustically microstructured cores.

Finite-element calculations of the Brillouin gain spectrum in photonic crystal fibers (PCFs) with cores incorporating random arrangements of regions with discrete acoustic velocities are presented. The peak Brillouin gain coefficient for PCFs with cores with an acoustic domain size of approximately 0.26 microm(2) and an acoustic velocity variation of 3% was calculated to be 3.3 x 10(-12) m/W with a Brillouin gain spectrum FWHM of 280 MHz. This corresponds to a decrease in the peak Brillouin gain coefficient of 7.4 dB relative to a PCF with an acoustically homogeneous core.

Finite element analysis of Brillouin gain in SBS-suppressing optical fibers with non-uniform acoustic velocity profiles.

A numerical investigation is presented of Brillouin gain in SBS-suppressing optical fibers with non-uniform acoustic velocity profiles. The equation determining the acoustic displacement in response to the electrostriction caused by the pump and Stokes waves reduces to the non-homogeneous Helmholtz equation for fibers with a uniform acoustic velocity profile. In this special case the acoustic displacement and subsequently the Brillouin gain are calculated using a Green's function. These results are then used to validate a finite-element solution of the same equation. This finite element method is then used to analyze a standard large mode area fiber as well as fibers incorporating four different acoustic velocity profiles with 5% variation in the acoustic velocity across the core. The profiles which suppress the peak Brillouin gain most effectively exhibit a maximum acoustic gradient near the midpoint between the center and boundary of the fiber core. These profiles produce 11 dB of suppression relative to standard large mode area fibers.

Stimulated Brillouin scattering continuous wave phase conjugation in step-index fiber optics.

Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber NA(2), but find that fidelity remains high over much longer fiber lengths than previous models calculated. Conditions for SBS beam cleanup in step-index fibers are discussed.

First experimental demonstration of self-synchronous phase locking of an optical array.

A novel, highly accurate, all electronic technique for phase locking arrays of optical fibers is demonstrated. We report the first demonstration of the only electronic phase locking technique that doesn't require a reference beam. The measured phase error is lambda/20. Excellent phase locking has been demonstrated for fiber amplifier arrays.