Photonic spiking neural network based on excitable VCSELs-SA for sound azimuth detection.

We propose a photonic spiking neural network (SNN) based on excitable vertical-cavity surface-emitting lasers with an embedded saturable absorber (VCSELs-SA) for emulating the sound azimuth detection function of the brain for the first time. Here, the spike encoding and response properties based on the excitability of VCSELs-SA are employed, and the difference between spike timings of two postsynaptic neurons serves as an indication of sound azimuth. Furthermore, the weight matrix contributing to the successful sound azimuth detection is carefully identified, and the effect of the time interval between two presynaptic spikes is considered. It is found that the weight range that can achieve sound azimuth detection decreases gradually with the increase of the time interval between the sound arriving at the left and right ears. Besides, the effective detection range of the time interval between two presynaptic spikes is also identified, which is similar to that of the biological auditory system, but with a much higher resolution which is at the nanosecond time scale. We further discuss the effect of device variations on the photonic sound azimuth detection. Hence, this photonic SNN is biologically plausible, which has comparable low energy consumption and higher resolution compared with the biological system. This work is valuable for brain-inspired information processing and a promising foundation for more complex spiking information processing implemented by photonic neuromorphic computing systems.

Broad autism phenotype features of Chinese parents with autistic children and their associations with severity of social impairment in probands.

BACKGROUND: Parents of children with autism have higher rates of broad autism phenotype (BAP) features than parents of typically developing children (TDC) in Western countries. This study was designed to examine the rate of BAP features in parents of children with autism and the relationship between parental BAP and the social impairment of their children in a Chinese sample. METHODS: A total of 299 families with autistic children and 274 families with TDC participated in this study. Parents were assessed using the Broad Autism Phenotype Questionnaire (BAPQ), which includes self-report, informant-report, and best-estimate versions. Children were assessed using the Chinese version of the Social Responsiveness Scale (SRS). RESULTS: Parents of children with autism were significantly more likely to have BAP features than were parents of TDC; mothers and fathers in families with autistic children had various BAP features. The total scores of the informant and best-estimate BAPQ versions for fathers were significantly associated with their children's SRS total scores in the autism group, whereas the total scores of the three BAPQ versions for mothers were significantly associated with their children's SRS total scores in the TDC group. In the autism group, the total SRS scores of children with "BAP present" parents (informant and best-estimate) were higher than the total SRS scores of children with"BAP absent" parents. In the TDC group, the total SRS scores of children with "BAP present" parents were higher than the total SRS scores of children with"BAP absent" parents (best-estimate). CONCLUSIONS: Parents of autistic children were found to have higher rates of BAP than parents of TDC in a sample of Chinese parents. The BAP features of parents are associated with their children's social functioning in both autism families and TDC families, but the patterns of the associations are different.

[Altered patterns of functional connectivity of posterior cingulate cortex on resting-state magnetic resonance imaging in children with attention-deficit or hyperactivity disorder].

OBJECTIVE: To explore the pathophysiological changes in the functional connectivity of posterior cingulate cortex (PCC) with other brain regions in children with attention-deficit or hyperactivity disorder (ADHD) on resting-state functional magnetic resonance imaging(fMRI) and explore the neural mechanisms of ADHD at the point of relationships between brain regions. METHODS: Thirty children with ADHD from the Third Affiliated Hospital of Soochow University from June 2008 to April 2010 and another 30 age-and-gender-matched controls from a normal primary school over the same period underwent resting-state fMRI scans. And blood oxygenation level dependent (BOLD) signal was acquired to calculate the functional connectivity of PCC with other brain regions controls. Significant differences of connectivity between groups were analyzed with REST software. RESULTS: The pattern of functional connectivity of PCC for the ADHD group was similar to that of the control group. Significant positive functional connectivity with PCC was observed in the default mode of network (DMN) while negative functional connectivity was present in dorsolateral prefrontal cortex, anterior cingulate, parietal cortex and basal ganglia(all P < 0.05, corrected). Compared to the controls, the ADHD group exhibited decreased positive connectivity with PCC in bilateral medial prefrontal cortex (0.07 ± 0.20 vs 0.33 ± 0.23, t = -5.47), right posterior cingulate gyrus(0.25 ± 0.28 vs 0.48 ± 0.30, t = -3.44), right inferior temporal gyrus (-0.05 ± 0.19 vs 0.22 ± 0.22, t = -4.61) and cerebellar posterior lobe (-0.04 ± 0.21 vs 0.17 ± 0.16, t = -3.99), while decreased negative functional connectivity with PCC was observed in left insula (-0.10 ± 0.26 vs -0.30 ± 0.19, t = 3.71), right inferior parietal lobule (0.02 ± 0.18 vs -0.23 ± 0.17, t = 5.20), left postcentral gyrus (0.08 ± 0.26 vs -0.17 ± 0.25, t = 4.06), left superior temporal gyrus (-0.04 ± 0.25 vs -0.27 ± 0.17, t = 4.27), right superior temporal gyrus (-0.08 ± 0.25 vs -0.31 ± 0.21, t = 3.80) and left fusiform gyrus (-0.01 ± 0.25 vs -0.18 ± 0.17, t = 3.57)(all P < 0.05, corrected). CONCLUSIONS: The connectivity of DMN between brain regions is abnormal in ADHD group. And the strengthen of negative relationship between DMN and task activated network becomes reduced. It is surmised that the decreased internal synchronization of default network and disrupted balance between DMN and prefrontal-parietal attentional networks may be important neural mechanisms of ADHD.

Difference in amplitude of low-frequency fluctuation between currently depressed and remitted females with major depressive disorder.

Medical intervention for major depressive disorder (MDD) can be more appropriately focused through the identification and characterization of neurobiological markers that are specific to the disorder, and this study aims to examine the abnormality in the fractional amplitude of low-frequency fluctuation (fALFF) and the amplitude of low-frequency fluctuation (ALFF) in currently depressed and remitted female MDD patients and to correlate these fluctuations with clinical markers of MDD. Nineteen currently depressed female patients, 19 remitted female patients, as well as 19 age- and education-matched healthy females participated in the resting-state functional magnetic resonance imaging (fMRI) analysis. We compared the fALFF/ALFF maps among the three groups and investigated the correlation between clinical measurements and statistically significant differences in the fALFF/ALFF of various brain regions. Compared with healthy controls, both currently depressed and remitted patients showed increased fALFF/ALFF in the right putamen. Currently depressed MDD patients showed increased fALFF/ALFF in the right ventral median frontal gyrus relative to both the remitted MDD group and the healthy control group. The ALFF of the right precuneus was found to be positively correlated with the number of depressive episodes and the fALFF of the right precuneus to be positively correlated with the disease duration in currently depressed MDD patients. An abnormal fALFF/ALFF in the right ventral median frontal gyrus was found only in currently depressed patients, suggesting that such an anomaly may play a critical role in depressive symptomatology and may be a therapeutic target for MDD. An abnormal fALFF/ALFF in the right putamen is a potential candidate as a trait-related marker of vulnerability to major depression.

[Mathematical cognitive function in children with attention deficit hyperactivity disorder: a behavior and event-related potential study].

OBJECTIVE: To explore the mathematics cognitive function of children with attention deficit hyperactivity disorder and explore neural mechanisms with event-related potential(ERP) and behaviors. METHODS: Behavior data and ERP elicited by performing mental calculation tasks were recorded in 27 children with ADHD and 29 normal controls from July to October 2012 at Third Affiliated Hospital of Soochow University.The differences of behaviors and N2 component of ERP were compared and analyzed. RESULTS: The reaction time of the children with ADHD were longer than the control group in addition, subtraction and multiplication ((949 ± 144) vs (829 ± 166) ms, (981 ± 129) vs (856 ± 170) ms, (944 ± 136) vs (825 ± 172) ms, all P < 0.05). While the correct rate were less than normal control in all three arithmetic operations (0.80% (0.72%, 0.88%) vs 0.90% (0.85%,0.96%), 0.78% (0.64%,0.85%) vs 0.90% (0.84%,0.93%), 0.86% (0.74%,0.92%) vs 0.93%(0.90%,0.98%), all P < 0.05). N2 component could be elicited by all subjects in forehead. The amplitude of N2 of children with ADHD were significantly lower than control group in all three arithmetic operations at left frontal (F3: (-3.5 ± 5.2) vs (-6.7 ± 3.5)µV, (-3.8 ± 4.0) vs (-7.4 ± 4.5)µV, -5.8 (-7.6,1.6) vs -6.4(-10.3, -4.9) µV, all P < 0.05) and Fz ((-4.3 ± 6.4) vs ( -7.4 ± 4.2) µV, (-5.0 ± 5.4) vs (-7.9 ± 4.6)µV, -5.2(-9.7, -0.6) vs -7.9 (-10.5, -5.1)µV, all P < 0.05), the latency of ADHD group were prolonger than controls in subtraction operations at right and left frontal ((328 ± 36) vs (307 ± 27)ms, 325 (307,354)vs 309 (280, 330)ms) and frontal electrodes ((331 ± 35) vs (311 ± 30) ms, all P < 0.05). In addition and multiplication operations, there was no significant difference in latency (all P > 0.05). CONCLUSIONS: The children with ADHD have weak capacities of inhibition irrelevant information and paying attention to control. Their deficits in mental arithmetics may be due to the difficulties of selecting the best strategy during cognitive tasks.

[Event-related potentials in character semantic priming of attention deficit hyperactivity disorder children and normal children: a comparative study].

OBJECTIVE: To investigate the cognitive event related potentials in Chinese character priming effect of children with attention deficit hyperactivity disorder (ADHD) and to analyze the neural mechanism of the priming effect. METHODS: Fifty-two ADHD children aged (9.5 +/- 1.7) and 45 age-matched children without ADHD were asked to perform a Chinese character semantic priming task while electroencephalogram was recorded. During the Chinese character semantic priming task the subjects were instructed to judge whether the presented target word was a related word, unrelated word, or a pseudoword and event-related potentials (ERPs) were elicited and analyzed with the brain electricity source analysis (BESA) software. RESULTS: (1) The behavioral results showed that the reaction time to the unrelated character stimuli in the ADHD children was (1252 +/- 256) ms, significantly longer than that in the normal control [(1131 +/- 194) ms, P < 0.05]. (2) The amplitude of the character related N2 at the Cz lead in the ADHD children was -7.7 (-12.8, -5.0) microV, significantly larger than that of the normal controls [-5.6 (-9.4, -3.2) microV, P < 0.05]. (3) The amplitude of character unrelated stimuli P3 at the Cz lead of the ADHD children was 5.4 (2.0, 9.5) microV, significantly lower than that of the normal control [9.5 (4.2, 16.9) microV, P < 0.01]. CONCLUSION: There is a positive correlation between the amplitude of N2 and the difficulty in character semantic priming. It is more difficult for the ADHD children than normal controls to accomplish the same semantic task. ADHD children need more attention resources than normal controls. The amplitudes of character related-N2 and unrelated-P3 may become markers to measure the development of recognition in the ADHD children, thus being helpful in the ADHD diagnosis.

[Cognitive development of normal school age children: a resting-state fMRI study].

OBJECTIVE: To investigate the characteristics of cognitive development in elementary school children using rest-fMRI methods. METHODS: Twenty-nine normal school children were divided into three groups according to their ages (8, 10 & 12 years old) and received the resting-state fMRI scans. A regional homogeneity (ReHo) approach was used to analyze blood oxygen level-dependent fMRI (BOLD-fMRI) data in resting state. The fMRI data were processed with software SPM2 and REST 1.2. RESULTS: Compared with younger groups (10 vs 8, 12 vs 10, 12 vs 8), the elder groups showed more increases in superior temporal gyrus (Z = 2.83, Z = 3.21), middle temporal gyrus (Z = 3.74, Z = 3.19, Z = 4.26), inferior temporal gyrus (Z = 3.01) and lentiform nucleus (Z = 3.31). In addition, the ReHo differences were demonstrated in superior frontal gyrus (Z = 3.21), middle frontal gyrus (Z = 3.19, Z = 3.22), medial frontal gyrus (Z = 3.15), lingual gyrus (Z = 3.43) and cerebellum (Z = 3.11, Z = 2.97) increased more in 12 years old group (12 vs 10, 12 vs 8). And the precuneus (Z = 2.95) and posterior cingulate (Z = 2.64) had increasing ReHo values with the age growth (12 vs 8). CONCLUSION: The function of execution control, accommodation of attention, visual spatial integration and default mode network became gradually developed with increasing age.

[Event-related potentials in Chinese characters semantic priming and arithmetic tasks: comparative study between healthy children and children with cognitive disorder].

OBJECTIVE: To explore the cognitive psychological process of healthy children and children with cognitive disorder. METHODS: Single Chinese character semantic priming and arithmetic tasks were delivered to 20 8-year-old healthy children, and 20 11-year-old healthy children, and 30 children with attention deficit hyperactivity disorder, 23 children with epilepsy, and 22 age-matched normal children as controls. Electroencephalography was used. Event-related potential was distilled by BESA software. RESULTS: (1) During the Chinese character semantic priming, the amplitudes of N2 toward the non-related words and pseudo-words in the 8-year-old group were 12.1 microV and 11.7 microV respectively, both significantly larger than those of the 11-year-old group (3.7 microV and 4.8 microV, respectively, both P<0.05). The amplitudes of N2 and P2 toward the non-related words and pseudo-words among the children with attention deficit hyperactivity disorder were both significantly lower than those in the healthy children (both P<0.05). (2) During the arithmetic task, the latency values of P2 and P3 of addition, subtraction, and multiplication in the 8-year-old group of healthy children were all significantly longer than those of the 11-year-old group of healthy children (all P<0.05). The P3 latency of the children with epilepsy was significantly longer than that of the healthy children (P<0.05). CONCLUSION: Chinese character and arithmetic cognitive waves are steady. ERP can be used to estimate the healthy children's personality index. Quantitative indicators are helpful in diagnosis and treatment of cognitive and learning disorders.