Schizotypy and Perceptual Learning: Aberrant Salience or Disrupted Inhibition?

精神分裂症是一个复杂的，异质性的诊断类别，其特征是幻觉，拥有不寻常的信念和混乱的认知和行为。症状在整个人群中连续变化，并且可以通过“典型性”的测量来检查一个人显示特征的程度。潜伏抑制（LI）是指与未预先暴露的条件刺激（CS）相比，在不存在非条件刺激（US）的情况下预先暴露于条件刺激（CS）会损害随后对CS和US之间关系的学习的现象。当代的学习模型表明，在预暴露期间，对CS的注意力下降，因为参与者了解到刺激并不意味着重大事件。LI在诊断为精神分裂症的个体中被破坏，并且与精神分裂症型特征呈负相关。Lubow（2005）认为，LI有助于将注意力引向相关刺激，远离不相关刺激。这些研究表明，具有高仿形性的个体分配注意力的效率较低，对不相关的刺激保持更多的注意力。有一种假说认为，幻觉的发生是由于对内部刺激的显著性的异常分配，而妄想则是在人们试图理解这些经历时产生的，这些理论虽然全面地解释了精神分裂症的阳性症状，但却忽略了阴性症状。然而，Kapur（2005）的理论可以扩展到解释抑郁症（DS），一种常见的阴性症状。精液研究表明，感知缺乏调节环境突发事件的能力需要抑郁症的因果关系的作用，人们可以概念化这作为一个环境结果（美国）和一个人的行动（CS）之间的关联。至关重要的是，发生这种情况的背景也与美国发展了一种联系，这样CS-US关系就与背景-US关系竞争行为控制。由于上下文信息是冗余的，它的显着性应该下降。然而，如果非预测性刺激在高仿形性个体中获得更大的显着性，则上下文的显着性将保持更长时间。由于显著性是学习的核心，在具有高显著性的个体中，上下文-US关联将相对较强，CS-US关联将相对较弱，最终在DS中达到顶峰。“感知学习”是指预先暴露于刺激有助于随后区分刺激的现象。McLaren et al（1989）解释了这一点，认为刺激包括许多元素，包括那些对每个刺激独特的元素和那些对两个刺激共同的元素。预暴露于两种刺激（例如CS-A和CS-B）导致共同元素的LI比独特元素相对更大。因此，对CS-A的了解不太容易推广到CS-B，从而促进了歧视。此外，CS-A的独特元件成为CS-B的独特元件的条件抑制剂。作者认为，共同的元素变得独立相关的两个刺激的独特元素，由于同时呈现。因此，CS-A在CS-B的独特元件不存在的情况下的呈现表现出预测误差，导致独特元件的条件性抑制。尽管有证据表明，知觉学习是依赖于LI和条件抑制，这是在个人与高仿型中断的现象，它仍然有待研究是否知觉学习是异常的，在个人与高仿型。本研究将探讨仿形性对知觉学习的影响，并阐明是否有任何异常可归因于中断的LI和/或中断的抑制协会。此外，本研究旨在阐明DS是否与LI或抑制性联想的发展有关，

Schizophrenia is a complex, heterogenous diagnostic category characterised by hallucinations, the possession of unusual beliefs and disorganised cognitions and behaviours. Symptoms vary on a continuum throughout the population and the extent to which one displays traits can be examined with measures of 'schizotypy'. Latent inhibition (LI) refers to the phenomenon that prior exposure to a conditioned stimulus (CS) in the absence of an unconditioned stimulus (US) impairs subsequent learning about the relationship between the CS and US, compared to a CS that has not been pre-exposed. Contemporary models of learning suggest that attention to the CS declines during pre-exposure, as participants learn that the stimulus does not signal a significant event. LI is disrupted in individuals with a diagnosis of schizophrenia and is inversely related to schizotypal traits. Lubow (2005) suggested that LI serves to direct attention towards relevant stimuli and away from irrelevant stimuli. These studies indicate that individuals with high schizotypy allocate attention less efficiently, maintaining greater attention towards irrelevant stimuli. It has been postulated that hallucinations occur consequential to the aberrant assignment of salience to internal stimuli and that delusions arise when one attempts to understand these experiences.Whilst these theories provide a comprehensive account of the positive symptoms of schizophrenia, they neglect the negative symptoms. However, Kapur's (2005) theory can be extended to account for depressive symptomology (DS), a common negative symptom. Seminal research indicated that the perceived absence of the ability to modulate environmental contingencies entails a causal role in depression; one can conceptualise this as an association between an environmental outcome (US) and one's actions (CS). Crucially, the context in which this occurs also develops an association with the US, such that the CS-US relationship is in competition with the context-US relationship for behavioural control. As contextual information is redundant, its salience should decline. However, if non-predictive stimuli acquire greater salience in individuals with high schizotypy, the context's salience will remain higher for longer. As salience is central to learning, the context-US association will be relatively stronger and the CS-US association will be relatively weaker in individuals with high schizotypy, culminating in DS.'Perceptual learning' refers to the phenomenon that pre-exposure to stimuli aids subsequent discrimination between the stimuli. McLaren et al (1989) explained this by suggesting that stimuli comprise a number of elements, composed of those that are unique to each stimulus and those that are common to both stimuli. Pre-exposure to both stimuli (e.g. CS-A and CS-B) results in relatively greater LI of the common elements than the unique elements. Accordingly, learning about CS-A generalises less readily to CS-B, facilitating discrimination. Moreover, the unique elements of CS-A become conditioned inhibitors of the unique elements of CS-B. The authors suggested that the common elements become independently associated with the unique elements of both stimuli, due to concurrent presentation. Therefore, presentation of CS-A in the absence of the unique elements of CS-B manifests a prediction error, resulting in conditioned inhibition of the unique elements. Despite evidence that perceptual learning is dependent upon both LI and conditioned inhibition, phenomena which are disrupted in individuals with high schizotypy, it remains to be examined whether perceptual learning is abnormal in individuals with high schizotypy. This research will examine the influence of schizotypy on perceptual learning and elucidate whether any abnormality is attributable to disrupted LI and/or disrupted inhibitory associations. Moreover, this study aims to elucidate whether DS is related to either LI or the development of inhibitory associa