Brain regions involved in subprocesses of small-space episodic object-location memory: a systematic review of lesion and functional neuroimaging studies

Object-location memory (OLM) enables us to keep track of the locations of objects in our environment. The neurocognitive model of OLM (Postma, A., Kessels, R. P. C., & Van Asselen, M. (2004). The neuropsychology of object-location memory. In G. L. Allen (Ed.), Human spatial memory: Remembering where (pp. 143–160). Mahwah, NJ: Lawrence Erlbaum, Postma, A., Kessels, R. P. C., & Van Asselen, M. (2008). How the brain remembers and forgets where things are: The neurocognition of object-location memory. Neuroscience & Biobehavioral Reviews, 32, 1339–1345. doi:10.1016/j.neubiorev.2008.05.001) proposes that distinct brain regions are specialised for different subprocesses of OLM (object processing, location processing, and object-location binding; categorical and coordinate OLM; egocentric and allocentric OLM). It was based mainly on findings from lesion studies. However, recent episodic memory studies point to a contribution of additional or different brain regions to object and location processing within episodic OLM. To evaluate and update the neurocognitive model of OLM, we therefore conducted a systematic literature search for lesion as well as functional neuroimaging studies contrasting small-space episodic OLM with object memory or location memory. We identified 10 relevant lesion studies and 8 relevant functional neuroimaging studies. We could confirm some of the proposals of the neurocognitive model of OLM, but also differing hypotheses from episodic memory research, about which brain regions are involved in the different subprocesses of small-space episodic OLM. In addition, we were able to identify new brain regions as well as important research gaps.     

Accessibility and characteristics of memories of the future

Recent research suggests that some imagined future events are encoded in memory, leading to the formation of “memories of the future”. However, questions remain regarding the exact components of future event simulations that are encoded and the factors that determine their accessibility. To address these questions, the present study investigated memory for previously imagined future events using both free and cued recall tasks. The results showed that most future event simulations were successfully encoded and remained available in memory after a one week delay, but only some of them were readily accessible, whereas others could only be accessed when relevant cues were provided. Persons and locations were particularly well remembered, suggesting that these components are central to the simulation and memorisation of future events. We also found that memory for future event simulations was related to the clarity and familiarity of represented persons, the subjective feelings of pre-experience and mental time travel, the importance of imagined events to personal goals, and their emotional intensity during the initial simulation phase. Taken together, these findings expand our understanding of the formation, accessibility, and characteristics of memories of the future.     

Inconsistent-handed advantage in episodic memory extends to paragraph-level materials

Past research using handedness as a proxy for functional access to the right hemisphere demonstrates that individuals who are mixed/inconsistently handed outperform strong/consistently handed individuals when performing episodic recall tasks. However, research has generally been restricted to stimuli presented in a list format. In the present paper, we present two studies in which participants were presented with paragraph-level material and then asked to recall material from the passages. The first study was based on a classic study looking at retroactive interference with prose materials. The second was modelled on a classic experiment looking at perspective taking and the content of memory. In both studies, the classic effects were replicated and the general finding that mixed/inconsistent-handers outperform strong/consistent-handers was replicated. This suggests that considering degree of handedness may be an empirically useful means of reducing error variance in paradigms looking at memory for prose level material.     

Reduced effects of pictorial distinctiveness on false memory following dynamic visual noise

High levels of false recognition for non-presented items typically occur following exposure to lists of associated words. These false recognition effects can be reduced by making the studied items more distinctive by the presentation of pictures during encoding. One explanation of this is that during recognition, participants expect or attempt to retrieve distinctive pictorial information in order to evaluate the study status of the test item. If this involves the retrieval and use of visual imagery, then interfering with imagery processing should reduce the effectiveness of pictorial information in false memory reduction. In the current experiment, visual-imagery processing was disrupted at retrieval by the use of dynamic visual noise (DVN). It was found that effects of DVN dissociated true from false memory. Memory for studied words was not influenced by the presence of an interfering noise field. However, false memory was increased and the effects of picture-induced distinctiveness was eliminated. DVN also increased false recollection and remember responses to unstudied items.     

Perceiving the Present: Systematization of Illusions or Illusion of Systematization?

Mark Changizi et al. (2008) claim that it is possible systematically to organize more than 50 kinds of illusions in a 7 × 4 matrix of 28 classes. This systematization, they further maintain, can be explained by the operation of a single visual processing latency correction mechanism that they call “perceiving the present” (PTP). This brief report raises some concerns about the way a number of illusions are classified by the proposed systematization. It also poses two general problems—one empirical and one conceptual—for the PTP approach.     

预见:情景记忆的未来投射与重构

预见是对有关个人的未来事件进行模拟的过程。相关的研究从几个方面展开:从比较心理学的角度探讨预见能力的种系发生图谱,从发展心理学的角度考察预见能力的发生发展状况,从认知神经科学的角度揭示预见过程的认知机制和神经基础。未来的研究应该补充和修正预见能力的种系发生图谱,揭示发展过程中预见能力与其他能力的关系,进一步考察卷入预见过程脑区之间的特定神经通路,并提高和拓展其社会应用的价值和范围。     

前临床期痴呆的认知特征：当前研究进展和未来研究展望

在这篇文章中, 我将讨论从正常老化到痴呆, 这一通常被称为痴呆前临床阶段的认知功能的转变。研究表明, 阿尔茨海默症和血管性痴呆病人在临床确诊之前的几年中, 会出现明显的认知损伤。早期最突出的损伤存在于情节记忆、加工速度以及执行功能。这些功能性损伤与神经生物学研究证实的边缘系统和新皮层区存在多重损伤是相一致的。虽然早在临床诊段之前, 病人组和控制组的平均成绩存在巨大差异, 但同时这两组测试成绩的分布在很大程度上是重叠的。寻求降低这种重叠度的方法是未来研究的一个重要任务。这有可能通过将认知的和其他指标(如基于脑的、基因的、临床的、社会的)相结合构建预测模型来实现。此外, 在未来研究中以下三方面也是急需考虑问题: (a) 找出在 前临床期间认知功能急速下降的时间点: (b) 评估从前临床到临床诊断变化速率中存在的个体差异; (c) 确定特定因素与随后发生的痴呆之间的关联强度是如何随时间向临床确诊推进而逐渐变化的。     

类别不确定下的特征推理是基于类别还是基于特征联结

共有3个实验探讨归类不确定情况下的特征推理是基于类别进行还是基于特征联结进行。实验1在中文条件下重复了Verde等人2005的实验,得出了与之相符的结果,这个结果用基于类别的理性模型的设想或者是用基于特征联结的设想都可以解释。实验2考察被试在靶类别的类别特征频次并且特征结合出现频次高低不同的条件下特征推理的情况,实验2的结果表明,高集中与低集中两种条件下特征推理没有显著差异,不符合特征推理是基于类别进行的设想,而与特征推理是基于特征联结进行的设想吻合。实验3进一步考察被试在特征结合出现的总频次并且靶类别中特征结合出现的总频次高低不同的条件下特征推理的情况,结果表明,在高结合条件下进行特征推理要优于在低结合条件,支持了在归类不确定情况下的特征推理是基于特征联结进行的设想。据此可以认为,人们的特征推理是基于特征之间联结的频次进行,而不是基于类别进行     

自身抗体与疾病预测

研究显示,在一些自身免疫性疾病出现临床症状之前,患者血液内就会出现某些自身抗体,检测这些自身抗体可以预测机体日后的患病几率,在疾病的预防和控制等方面具有重要意义。本文将对部分疾病中预示性自身抗体的研究进展及用自身抗体预测疾病的价值和面临的挑战等问题作一综述。