Schizotypy and Perceptual Learning: Aberrant Salience or Disrupted Inhibition?

精神分裂和知觉学习：异常的显着性还是破坏的抑制？

• 批准号: 2591078
• 金额: --
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2591078
• 关键词: Schizotypy; Perceptual; Learning; Aberrant; Salience

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

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、拥有不寻常的信念以及混乱的认知和行为。症状在整个群体中都是不同的，一个人表现出特征的程度可以通过“分裂类型”的测量来检查。潜伏抑制(LI)是指与没有预先暴露的条件刺激相比，在没有条件刺激(US)的情况下，预先暴露于条件刺激(CS)会损害对CS和US之间关系的后续学习的现象。当代的学习模型表明，在暴露前，人们对CS的注意力下降，因为参与者了解到刺激并不是重大事件的信号。在被诊断为精神分裂症的个体中，LI被扰乱，并且与分裂型特征呈负相关。卢博(2005)提出，理应将注意力从无关的刺激转移到相关的刺激上。这些研究表明，高度分裂类型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。据推测，幻觉的产生是由于异常地将突显分配给内部刺激，当一个人试图理解这些经历时，就会产生妄想。尽管这些理论对精神分裂症的积极症状提供了全面的解释，但它们忽略了消极症状。然而，Kapur(2005)的理论可以扩展到解释抑郁症状(DS)，这是一种常见的阴性症状。开创性的研究表明，感知到的缺乏调节环境偶发事件的能力会导致抑郁症；人们可以将其概念化为环境结果(美国)和行为(CS)之间的关联。至关重要的是，发生这种情况的背景也发展了与美国的联系，使得CS-US关系与背景-美国关系在行为控制方面展开竞争。由于背景信息是多余的，它的重要性应该会下降。然而，如果非预测性刺激在高度分裂类型的个体中获得更大的突显，背景的突显将在更长的时间内保持更高的水平。由于突显是学习的核心，在高度分裂类型的个体中，情境-美国联系相对较强，CS-美国联系相对较弱，最终导致DS。“知觉学习”指的是预先接触刺激有助于随后对刺激进行区分的现象。麦克拉伦等人(1989)解释说，刺激由许多元素组成，这些元素由每个刺激特有的元素和两个刺激共同的元素组成。预先暴露于两种刺激(例如CS-A和CS-B)会导致共同元素的LI比独特元素的LI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的独特成分成为CS-B独特成分的条件性抑制因子。作者认为，由于同时呈现，共同因素变得独立地与两种刺激的独特因素相关。因此，在没有CS-B的独特成分的情况下呈现CS-A表现出预测错误，导致对独特成分的条件性抑制。尽管有证据表明知觉学习依赖于LI和条件性抑制，但高分裂类型个体的知觉学习是否异常仍有待检验。这项研究将考察分裂类型对知觉学习的影响，并阐明任何异常是否可归因于LI和/或抑制联系中断。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