Speed of processing within semantic memory following severe closed head injury.

This study investigated the effects of severe closed head injury (CHI) on the speed of information processing within semantic categories. The question of whether subjects were able to benefit from priming was also investigated. Survivors of severe CHI who were less than 1 year postinjury and survivors who were greater than 1 year postinjury were compared with neurologically normal matched controls utilizing a category judgement task. The results demonstrated slower processing within semantic memory for both groups of CHI patients compared to normal controls. Furthermore, individuals with CHI were able to benefit from priming to the same relative degree as control subjects. Overall, the results suggested semantic organization remains intact after severe CHI, but accessing semantic information is slowed.     

Selective Processing of Threat Cues in Subjects with Panic Attacks

Abstract

Previous research has demonstrated that patients with generalised anxiety disorder, phobias, and obsessive-compulsive disorder show an attentional bias towards threat cues related to their respective disorders. Two studies are presented that used a modified Stroop colour naming task to assess attentional bias in subjects with panic attacks. In Study 1, 24 panic disorder patients and 24 normal controls were presented three cards containing threat words related to physical harm, separation, or social embarrassment. Colour naming times were compared between these cards and control cards containing matched non-threat words. Reaction time differences in the two groups were in opposite directions, patients tending to be slower in colour naming threat words, and controls, faster. In Study 2, 18 non-clinical panickers and 18 controls were presented cards containing physical threat words, neutral control words, or colour words, respectively. Panickers showed greater interference than controls in colour naming threat words but not in colour naming colour words. The results are consistent with an attentional bias for threat-related material in subjects with panic attacks. Implications for psychophysiological models of 'spontaneous' panic attacks are discussed.     

A follow-up study of cognitive bias in generalized anxiety disorder

Patients with generalized anxiety disorder (GAD) without concurrent depression (n = 11) and normal controls (n = 17) were tested twice, about 2 months apart, on a modified Stroop colour-naming task, which presented anxiety-related, depression-related and neutral words in masked and unmasked exposure conditions. GAD patients received cognitive behaviour therapy in the test-retest interval, and were also retested at follow-up, about 20 months after initial testing. GAD patients showed interference in colour-naming negative words across both masked and unmasked conditions before treatment, but not post-treatment, compared with controls. Reduced interference effects of masked threat words over time correlated with reduced ratings of anxious thoughts at post-treatment, and at follow-up, in GAD patients. Thus, the preconscious bias for threat information in GAD appears to vary over time in association with changes in anxious thoughts and worries.     

Attentional bias to threat: Roles of trait anxiety, stressful events, and awareness

Attentional biases for threat stimuli were assessed in high and low trait anxious subjects (n = 66) using a probe detection task. To examine the effects of trait anxiety and situational stressors, each subject was tested three times: Under no stress, laboratory-induced stress, and examination-induced stress. To evaluate the role of awareness, half the word stimuli were presented very briefly (14 msec) and masked, and the other half were presented for 500 msec without a mask. Results showed that high trait anxious subjects under exam stress showed an attentional bias towards unmasked threat stimuli compared with low trait subjects. This effect was not found under lab-induced stress, suggesting that the attentional bias for unmasked threat in high trait subjects may be a function of a prolonged stressor, rather than a transient increase in state anxiety. The results from the masked exposure condition were not predicted; high trait anxious subjects shifted attention towards the spatial location of threat words despite lack of awareness of their lexical content, but this bias was only apparent in the no-stress condition. The results are discussed in relation to recent cognitive theories of anxiety.     

Cognitive processing of emotional information in depression, panic, and somatoform disorder

Emotional Stroop tasks (subliminal/supraliminal exposures), implicit memory tasks (tachistoscopic word identification), and explicit memory tasks (free recall after incidental learning) with 4 word types (physical threat, positive, negative, and neutral words) were administered to patients with major depressive disorder (n=30), panic disorder (n=33), somatoform disorder (n=25), and healthy control participants (n=33). On the Stroop task, panic patients showed subliminal interferences for physical threat and negative words, depressive patients showed supraliminal interferences for negative words, and somatoform patients showed supraliminal interferences for physical threat words. No patient groups demonstrated implicit memory biases. On the explicit memory task, depressive and panic patients showed memory biases for negative words; somatoform patients showed biases for physical threat words.     

Cognitive Correlates of Social Phobia Among Children and Adolescents

We examined different cognitive phenomena in relation to social phobia among children (aged 7 to 11) and adolescents (aged 12–16) separately. Fifty socially phobic youths were compared to 30 normal control children on measures of social anxiety, social expectation as well as self- and observer-rated performance during two social tasks involving a same-aged peer. Additionally, a video-mediated recall procedure was conducted immediately following the two behavioral tasks to examine specific types of self-talk. Results indicated that socially phobic youths had lower expectations of their performance and rated their actual performance worse than controls during a social interaction task, but not a read-aloud task. Self-ratings of decreased performance among socially phobic youths were corroborated by blind observers. Although differences in specific types of self-talk were found between the two groups, these findings were generally moderated by age. Furthermore, certain cognitive symptoms associated with the disorder were more commonly found among older socially phobic youths. The current findings highlight the importance of considering developmental factors in the presentation and treatment of social phobia in youths.     

Interpretation and judgmental biases in social phobia

Previous research demonstrated that social phobia is characterized by content-specific interpretation and judgmental biases. The present study investigated whether this interpretation bias occurs not only in ambiguous, but also in positive and negative social events, and whether social phobic patients (SPs) are more characterized by a judgmental bias in costs than in probability. Besides, we argued that the judgmental bias observed in former studies could also be attributed to accurate estimations of SPs (of, for example, stuttering). Therefore, we assessed judgmental bias by the ratings of probability and costs of a negative evaluation (e.g. ‘people dislike me’) and not, as in previous studies, of negative social events (e.g. ‘stuttering’). SPs (n=228) and normal controls (n=33) were presented social and non-social events ranging from positive to profoundly negative. They ranked four different interpretations on likelihood to assess interpretation bias, and rated the profoundly negative interpretation on probability and cost to assess judgmental bias. SPs demonstrated content-specific interpretation and judgmental biases that also occurred in positive and negative social events. In contrast with expectations, SPs were characterized by a judgmental bias in both costs and probability.     

Selective processing of threat cues in panic disorder

A computerized Stroop color-naming paradigm was used to investigate attentional biases for selectively processing threat information in panic-disordered patients. Subjects named the colors of neutral words (e.g. TYPICAL), fear words (e.g. PANIC), bodily sensation words (e.g. HEARTBEAT), and catastrophe words (e.g. HEART ATTACK). To control for familiarity with threat concepts, we used clinicians who treat panic disorder as normal control subjects. In contrast to normal controls, panic patients exhibited greater Stroop interference for all threat words, especially those associated with catastrophe. Stroop interference waned during the course of the experiment, thereby indicating habituation to the semantic content of the cues. These findings suggest that panic disorder, like other anxiety disorders, is associated with an attentional bias for processing threatening information.     

Perceptual priming is not a necessary consequence of semantic classification of pictures

Four experiments investigated how repetition priming of object recognition is affected by the task performed in the prime and test phases. In Experiment 1 object recognition was tested using both vocal naming and two different semantic decision tasks (whether or not objects were manufactured, and whether or not they would be found inside the house). Some aspects of the data were inconsistent with contemporary models of object recognition. Specifically, object priming was eliminated with some combinations of prime and test tasks, and there was no evidence of perceptual (as opposed to conceptual or response) priming in either semantic classification task, even though perceptual identification of the objects is required for at least one of these tasks. Experiment 2 showed that even when perceptual demands were increased by brief presentation, the inside task showed no perceptual priming. Experiment 3 showed that the inside task did not appear to be based on conceptual priming either, as it was not primed significantly when the prime decisions were made to object labels. Experiment 4 showed that visual sensitivity could be restored to the inside task following practice on the task, supporting the suggestion that a critical factor is whether the semantic category is preformed or must be computed. The results show that the visual representational processes revealed by object priming depend crucially on the task chosen.     

Colour specificity in episodic and in perceptual object recognition with enhanced colour impact

In three experiments we investigated the perceptual specificity of explicit (old-new object recognition) and implicit memory (word-picture matching) for colour. In order to enhance the impact of colour on processing, we increased the number of colours per object and we impaired shape information. We presented multicoloured pictures (Experiment 1), blurred and partially occluded pictures (Experiment 2) and coloured line drawings in visual noise (Experiment 3). Experiments 1 and 2 had an intentional study phase; the study phase of Experiment 3 was an incidental colour or category naming task. Changing colour from study to test always had negative effects on episodic recognition although colour was irrelevant. In contrast, in the matching task old pictures were generally matched faster than new ones independent of their colour congruence. In Experiment 3, an additional small advantage of congruent colours and of semantic processing occurred. We conclude that two different memory representations contribute to these tasks. Changes of an achromatic, more abstract representation, that is used in normal object recognition, and a representation of the specific exemplar that includes colour. This latter token is used in episodic recognition as well as in unusual perceptual tasks (Experiment 3).     

Non-specific encoding of threat in social phobia and panic disorder

This study employs a release of proactive interference technique to explore encoding-related processes in social phobia. Twenty-six individuals with social phobia and 24 individuals with panic disorder participated in the memory task. Significant release of proactive interference was found when neutral and threat dimensions were encoded, but not when social and physical threat dimensions, or when positive and threat dimensions were presented. Threat was therefore differently encoded depending on the active encoding context in which semantic processing occurred. Individuals with social phobia or panic disorder did not differ in the release of proactive interference. The present experiment consequently yields little support for the specificity hypothesis in memory of anxious individuals. Instead, the findings generally demonstrate that threat encoding is similar for people with social phobia and those with panic disorder.     

基底神经节损伤对知觉性启动效应影响的进一步研究

基底神经节的认知和记忆功能是近年认知神经科学研究的热点。该研究采用两项语义性启动效应（自由联想、偏好）和一项知觉性启动效应（字辨认）任务,发现基底神经节损伤、分别伴两侧海马或右侧丘脑损伤的两例患者的语义性启动效应正常,知觉性启动效应障碍。由于先前研究已经证实海马或丘脑结构与启动效应无关,因此该两例患者表现的知觉性启动效应障碍可归因于基底神经节损伤,进一步证实了王常生等人认为基底神经节可能具有或参与知觉性启动效应调节作用,与语义性启动效应无关的观点。     

色觉疲劳、语义饱和对颜色范畴知觉的即时影响

颜色范畴知觉究竟是语言的还是知觉的, 或两者交互引起的认知冲突所致仍在探究与争议之中。本研究采用色觉疲劳和语义饱和操作分别独立地改变知觉或语义加工, 观察二者对颜色范畴知觉效应的即时影响, 以期探究语言和知觉对颜色范畴的作用。结果显示, 色觉疲劳操作导致范畴间颜色辨别反应时减少, 颜色范畴效应增强。语义饱和操作导致被饱和颜色词所属的范畴内颜色辨别反应时增加, 颜色范畴效应增强。说明单独改变知觉或语义加工能力均能影响CCP效应, 支持了语言标签对比模型, 即语言与知觉的交互作用引起颜色范畴知觉的观点。     

Involuntary aware memory enhances priming on a conceptual implicit memory task

This study investigated the role of involuntary aware memory (phenomenological awareness of the study episode) on a conceptual implicit memory task. Subjects studied words under levels of processing conditions (LOP: nonsemantic vs. semantic) and then received a category exemplar generation priming task. Subjects were either aware or unaware of the study test relationship. Subjects who were study test aware showed more priming for semantic study than subjects who were study test unaware, thus producing an LOP dissociation between them. The findings suggest that involuntary aware memory can enhance performance on conceptual implicit memory tasks, thus having theoretical implications for implicit and explicit memory.     

Through the eyes of anxiety: Dissecting threat bias via emotional-binocular rivalry

An extensive body of research has demonstrated that anxious individuals abnormally process threat-related content. Yet, the manner in which clinical anxiety affects the selection of threatening signals and their maintenance within consciousness is yet to be explored. The present study used an emotional binocular rivalry (e-BR) procedure, in which pictures of faces depicting either fearful or neutral expressions competed with pictures of a house for conscious perception. We assumed that first- or cumulative-preferred perception of faces with fearful over neutral expression (i.e., initial or sustained threat bias, respectively) stand for preferential selection or maintenance of fear content in awareness, correspondingly. Unmedicated patients with social anxiety disorder (SAD) and panic disorder (PAD) were compared to healthy controls for threat-related perceptual biases in the e-BR. At first perception of face, both SAD and PAD patients showed a greater initial threat bias than healthy controls. In contrast, at cumulative dwell-time of face, patient groups demonstrated a diminished sustained threat bias relative to healthy controls, yet in a different manner. SAD patients showed a sustained threat bias, though it was smaller than in healthy controls. Furthermore, increased levels of reported anxiety among SAD patients were associated with enhanced sustained perception of neutral faces. PAD patients, on the other hand, showed no sustained threat bias and a diminished cumulative perception of fearful faces with increased levels of anxiety traits. These findings indicate that anxiety disorders commonly involve an initially enhanced selection of threat signals into awareness, followed by disorder-specific manifestation of diminished preferred maintenance of threat in awareness. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Non‐specific encoding of threat in social phobia and panic disorder

This study employs a release of proactive interference technique to explore encoding‐related processes in social phobia. Twenty‐six individuals with social phobia and 24 individuals with panic disorder participated in the memory task. Significant release of proactive interference was found when neutral and threat dimensions were encoded, but not when social and physical threat dimensions, or when positive and threat dimensions were presented. Threat was therefore differently encoded depending on the active encoding context in which semantic processing occurred. Individuals with social phobia or panic disorder did not differ in the release of proactive interference. The present experiment consequently yields little support for the specificity hypothesis in memory of anxious individuals. Instead, the findings generally demonstrate that threat encoding is similar for people with social phobia and those with panic disorder.     

Contribution of perceptual and lexical-semantic errors to the naming impairments in Alzheimer's disease

The contribution of perceptual and semantic processing deficits to naming-test performance by Alzheimer's Disease subjects was examined. Groups of 34 Alzheimer subjects and 25 elderly controls completed tests of naming standard line drawings and naming perceptually degraded figures, and a test of verbal fluency for a specific semantic category. Alzheimer subjects were impaired on all measures and, when their naming-test errors were analyzed, they showed higher proportions of perceptual errors and failures to respond. Further, considerable variability in the proportions of different types of error was found both among subjects and among test items. These findings indicate that poor naming-test performance cannot necessarily be attributed to a specific deficit in semantic processing. Also, the discrepancies between previous reports of the naming deficits in Alzheimer's Disease may reflect differences in task difficulty and item selection that were apparent in this study.     

Negative priming is not task bound: A consistent pattern across naming and categorization tasks

When a word that was a to-be-ignored flanker on an initial prime trial becomes the target on the subsequent probe trial, responding to that word on the probe trial is slowed, a phenomenon callednegative priming. Virtually all prior studies have required subjects to perform the same task on both the prime and the probe trials. Thus, the extent to which negative priming is task bound is uncertain. We manipulated task factorially on the prime and probe trials, resulting in four groups: name-name, name-categorize, categorize-name, and categorize-categorize. The results showed equivalent negative priming of about 22 msec both within and between tasks for identical words, but no negative priming for semantically related words from the same category. These findings suggest (1) that negative priming for identical words can readily cross task types; and (2) that semantic negative priming does not occur for words, at least when categorical relatedness alone determines the semantic relation.     

Specific phonological impairments in dyslexia revealed by eyetracking

Phonological deficits in dyslexia are typically assessed using metalinguistic tasks vulnerable to extraneous factors such as attention and memory. The present work takes the novel approach of measuring phonology using eyetracking. Eye movements of dyslexic children were monitored during an auditory word recognition task in which target items in a display (e.g., candle) were accompanied by distractors sharing a cohort (candy) or rhyme (sandal). Like controls, dyslexics showed slower recognition times when a cohort distractor was present than in a baseline condition with only phonologically unrelated distractors. However, unlike controls, dyslexic children did not show slowed recognition of targets with a rhyme distractor, suggesting they had not encoded rhyme relationships. This was further explored in an overt phonological awareness test of cohort and rhyme. Surprisingly, dyslexics showed normal rhyme performance but poorer judgment of initial sounds on these overt tests. The results implicate impaired knowledge of rhyme information in dyslexia; however they also indicate that testing methodology plays a critical role in how such problems are identified.