Increased attention towards threatening stimuli in both the external and internal environments is thought to be a factor in the causation and maintenance of pathological anxiety. Attentional biases for threatening information have been demonstrated in anxiety disorders, however the cortical mechanisms involved remain unclear. In this investigation, an Emotional Stroop task consisting of neutral, positive, depression-related and anxietyrelated words, was used to investigate attentional biases in 14 Panic Disorder patients and 32 psychiatrically healthy controls. The standard colour-word Stroop was also performed to determine whether any general cognitive deficits exist in Panic Disorder. Steady-state probe topography (SSPT), a brain electrical activity imaging methodology, was used to investigate participants' brain activity during performance of the tasks. It was hypothesised that Panic Disorder is associated with specific biases for disorder-specific information and thus patients would exhibit increased interference for anxiety-related words only, compared to neutral words. Mean reaction times for the Standard Stroop was similar for the two groups. For the Emotional Stroop task, neither group showed an interference effect for any emotional category. However, Panic Disorder patients performed the Emotional Stroop significantly more slowly than the Controls. The SSPT data suggest that the Standard and Emotional Stroop tasks are associated with different patterns of brain activity in the Control and Panic Disorder groups despite the similarities in the reaction time data. Specifically, the Standard Stroop was marked by strong temporo-parietal excitation in the Panic Disorder group only. In addition, anterior SSVEP patterns further differentiated between the Control and Panic Disorder groups. The most striking finding for the Emotional Stroop was strong sustained bilateral temporo-parieto-occipital excitation in the Panic Disorder group. In addition, a subgroup of the Controls exhibited increased interference for anxiety-related words and therefore the brain activity for this group and the remainder of Controls who did not show interference was analysed separately. It was found that the presence of interference for anxiety-related words was associated with right prefrontal inhibition prior to response. Other time-varying changes in the SSVEP further distinguished between the subgroup of Controls who showed an interference effect and those who did not.

對於精神分裂症患者注意力歷程缺失現象的探討，過去大多集中在 對注意力歷程本身機制的探究；但在結果上一直找不到令人滿意的解釋． 然而在心理學的研究中發現， 個體在進入注意力歷程對刺激做進一步處 理之前，有一個前注意力歷程會先對視野中所現刺激做整體性的處理；之 後才能使個體經由選擇將注意力集中在所欲處理的訊息上，此即注意力歷 程二階段論． 本研究即以注意力歷程二階段論為起點，利用兩個以擬 似叫色作業進行的實驗去區辨精神分裂症患者在注意力表現的異常，究竟 導因於那一階段的運作失常．本研究的兩個實驗均是以伴隨分心項同時呈 現的 Stroop 色字為實驗刺激，藉由操弄目標項（ 即Stroop色字）刺激 類型及分心項與目標項間關係，觀察精神分裂症患者與正常在前注意力歷 程運作上有何差異，並期能據此瞭解精神分裂症患者注意力歷程缺失的可 能原因． 綜合兩實驗所得結果，精神分裂症患者在前注意力歷程的運 作上與正常人並無差別；但在進入注意力歷程對刺激做進一步處理時，抑 制機制的運作失常（運作不足或運作過度）為其注意力失常的可能原因之 一，但仍無法對本研究的結果作一完整的說明．此外，由研究結果中，也 可推測精神分裂症患者在對目標項進行細部分析時，其持續性的注意力也 有異於正常人；這部份仍有待進一步的研究． / There is a wealth of literature associating schizophrenia withdisorders of attention. This study bases on the two-stage approach of visual selective attention. The pre- attentiveparallel processcomputes how different each object is from each of the other objectswithin a particular stimulus dimension. Attention automatically drawto the location having the highest activation, implying that the subjects select location automatically and are irrespective of their intention. Two Stroop tasks used to differentiate schizophrenics and nornalic'sattentional processes, and try to figure out which stageis the caution of schizophrenic's dysfunctional attention. As the result, schizophrenic is not different with normalics on pre-attentiveprocess, but do have something problem onattentional process when theywhen they have to inhibit some information. It'sstill not a conclution,because the deficit of inhibition can not explain the results perfectly.

The purpose of this study is to investigate the usefulness of a 20-minute brief mindfulness meditation in positively affecting mood and attention. Its effects were compared with the effects from a period of distraction and a control condition. The sample consisted of 63 veterans with Posttraumatic Stress Disorder. Pre-post test of the State-Trait Anxiety Inventory and the Positive and Negative Affect Schedule were used to assess levels of state anxiety and mood. The Stroop Task was employed as a measure of selective attention. A one-way analysis of variance and split-plot analysis of variance were conducted. To control high comorbidity within this sample, sub-analyses were conducted excluding participants with other psychological or physical conditions. The results revealed that meditators without sleep problems indicated greater selective attention levels. A negative mood decrease was found in all participants regardless of the intervention group assignment. Implications for research and practice were discussed.

Neurons are connected to form functional networks in the brain. When neurons are combined in sequence, nontrivial effects arise. One example is disinhibition; that is, inhibition to another inhibitory factor. Disinhibition may be serving an important purpose because a large number of local circuits in the brain contain disinhibitory connections. However, their exact functional role is not well understood. The objective of this dissertation is to analyze the computational role of disinhibition in brain function, especially in visual perception and attentional control. My approach is to propose computational models of disinhibition and then map the model to the local circuits in the brain to explain psychological phenomena. Several computational models are proposed in this dissertation to account for disinhibition. (1) A static inverse difference of Gaussian filter (IDoG) is derived to account explicitly for the spatial effects of disinhibition. IDoG can explain a number of complex brightness-contrast illusions, such as the periphery problem in the Hermann grid and the White's effect. The IDoG model can also be used to explain orientation perception of multiple lines as in the modified version of Poggendorff illusion. (2) A spatio-temporal model (IDoGS) in early vision is derived and it successfully explains the scintillating grid illusion, which is a stationary display giving rise to a striking, dynamic, scintillating effect. (3) An interconnected Cohen-Grossberg neural network model (iCGNN) is proposed to address the dynamics of disinhibitory neural networks with a layered structure. I derive a set of sufficient conditions for such an interconnected system to reach asymptotic stability. (4) A computational model combining recurrent and feed-forward disinhibition is designed to account for input-modulation in temporal selective attention. The main contribution of this research is that it developed a unified framework of disinhibition to model several different kinds of neural circuits to account for various perceptual and attentional phenomena. Investigating the role of disinhibition in the brain can provide us with a deeper understanding of how the brain can give rise to intelligent and complex functions.

Childhood emotional maltreatment is associated with damaging consequences, although relatively little is known about the mechanisms underlying its effects. This dissertation investigated the concurrent influences of adult attachment and mindfulness on internalizing symptoms and emotional processing in young adults with and without a history of emotional maltreatment. Study 1 revealed that a sequential mediation model, with adult attachment orientations as first-step mediators and mindfulness as a second-step mediator, fit the data better than a simultaneous mediation model. In addition, moderation analyses revealed that high self-reported levels of mindfulness protected against the development of internalizing symptoms, even in at-risk individuals. Study 2 replicated these findings in a new sample, while also extending the results beyond a self-report outcome, using behavioural measures of emotional processing. Emotional maltreatment, adult attachment, and mindfulness predicted the amount of perceptual information required to correctly identify fearful faces and the amount of interference demonstrated in response to positive and negative emotional words. Cumulatively, these findings suggest that childhood emotional maltreatment can disrupt attachment relationships and encumber the development of mindfulness, contributing to internalizing symptoms and the biased processing of emotional information. However, alternative outcomes are possible, given the presence of high levels of mindfulness and secure attachment representations. This has implications for clarifying developmental theories and evaluating clinical interventions that may mitigate the negative effects of childhood emotional maltreatment.

Living environments are seldom, if ever, devoid of all background auditory stimuli. However, the relationship between particular structural components of acoustic backgrounds and cognitive task performance remains unclear. Two experiments were completed to examine the influence of sound on a visual selective attention task. Participants performed the Stroop task (Stroop, 1935) while silence or background acoustic patterns of various complexities were presented over headphones. No effect of background sound on performance was found. A post-hoc analysis indicated that in comparison with participants who do not regularly listen to music while studying, participants who regularly listen to music while studying performed better on the Stroop task when a structured auditory pattern that included variation in both frequency and time interval was presented in the background. These results indicate that distinct structural components of background auditory sequences may interact with individual characteristics to influence cognitive performance on a task involving selective attention.

Living environments are seldom, if ever, devoid of all background auditory stimuli. However, the relationship between particular structural components of acoustic backgrounds and cognitive task performance remains unclear. Two experiments were completed to examine the influence of sound on a visual selective attention task. Participants performed the Stroop task (Stroop, 1935) while silence or background acoustic patterns of various complexities were presented over headphones. No effect of background sound on performance was found. A post-hoc analysis indicated that in comparison with participants who do not regularly listen to music while studying, participants who regularly listen to music while studying performed better on the Stroop task when a structured auditory pattern that included variation in both frequency and time interval was presented in the background. These results indicate that distinct structural components of background auditory sequences may interact with individual characteristics to influence cognitive performance on a task involving selective attention.

One means by which inhibitory control in selective attention may be studied is with the negative priming (NP) procedure. It is widely assumed that children are characterised by reduced capacity for inhibition (Diamond, 2002) and that inhibitory dysfunction is a key characteristic of children and adolescents with ADHD (Barkley, 1997). This should translate into reduced NP effects for these populations. In this dissertation, four studies using the NP procedure find no evidence for reduced inhibitory function in typical children or in adolescents with ADHD. Study 1 examined the magnitude of NP in children compared with adults. An important line of support for the idea that children suffer an inhibitory decrement has been based an empirical report suggesting that conceptual (identity or semantic) NP effects, assumed to reflect the by-product of distractor inhibition, while consistently found in adults are lacking in children (Tipper, Bourque, Anderson, & Brehaut, 1989). In Study 1, the opposite result was found. Study 2 compared NP effects between 7-year-old children and adults while replicating the respective methodologies of the only two studies to explore conceptual NP effects in developmental populations to date (Pritchard & Neumann, 2004, vs. Tipper et al., 1989) to determine the nature of the divergent results between these studies. In Study 2, it was found that distractor inhibition effects are comparable between children and adults when a NP task contains trials in which the distractor stimulus is consistently incongruent with the target stimulus, but that children may be more susceptible than adults to divide attention between target and distractor when a NP task contains a number of trials in which target selection difficulty is reduced. These are critical new findings, highlighting that reduced NP may often relate to methodological artifacts, and when considered in the light of current theories of NP, are also problematic for anti-inhibitory accounts of NP. Having distinguished more definitively the role of inhibition in developmental NP effects, Studies 3 and 4 explored whether the inhibitory process underpinning NP was implicated in young persons with ADHD. To date, evidence for NP in ADHD populations is equivocal. Study 3 found no evidence for a reduced NP effect in ADHD devoid of a corresponding diagnosis. Study 4 found that conduct and oppositional defiant disorders had the potential to confound the evaluation of NP in ADHD. Taken together, results in Studies 1 - 4 parallel very recent results in the literature on NP in older adults and adult psychopathology where presumed reductions of NP in these populations may also be accounted for by methodological artifacts (Buchner & Mayr, in press). It is concluded that NP may reflect a primitive and robust form of inhibitory processing, one that develops early and one that is often the last to deteriorate.

The smartphone has quickly become the most used device to access the internet. Academic and public concern has been raised if overuse of smartphone technology can have detrimental effects on brain and behavior. Preliminary results suggest that excessive smartphone usage may be linked to impaired inhibitory control. The present study investigates whether such a relationship is present in a sample of healthy individuals with varying degrees of usage. To investigate the proposed relationship, the Stroop color and word task and the stop-signal task was utilized to measure inhibitory control, while screen time was utilized to measure duration of smartphone usage. A Pearson‘s correlation analysis and an independent t-test/Mann Whitney-U test analyzed the results, which did not yield statistical significance.

Master’s thesis deals with the measurement of biological signals for the effect of psychological burden. To monitor this effect was elected Stroop test, which is in the psychology used to detect disorders of attention and concentration. EEG and ECG signals during Stroop test were obtained using the EEG recording systém, in the context of research evoked potentials. As a part of the work it has been designed custom application for analyzing and interpreting data and statistical analysis by t-test.