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Sharma G, Chitturi V, Sharma VK, Kathrotia R, Barde P, Parmar N, Sharma M, Singh RD. Innovative strategies for managing hallucinations by exploring effects of tDCS on source monitoring abilities. Sci Rep 2024; 14:16569. [PMID: 39019949 PMCID: PMC11254933 DOI: 10.1038/s41598-024-67279-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 07/09/2024] [Indexed: 07/19/2024] Open
Abstract
This randomised, crossover, sham-controlled study explored the neural basis of source-monitoring, a crucial cognitive process implicated in schizophrenia. Left superior temporal gyrus (STG) and dorsolateral prefrontal cortex (DLPFC) were the key focus areas. Thirty participants without neurological or psychological disorders underwent offline sham and active tDCS sessions with specific electrode montage targeting the left STG and DLPFC. Source-monitoring tasks, reality monitoring (Hear-Imagine), internal source-monitoring (Say-Imagine), and external source monitoring (Virtual-Real) were administered. Paired t-test and estimation statistics was performed with Graphpad version 10.1.0. The Benjamini-Hochberg procedure was employed to control the false discovery rate in multiple hypothesis testing. A significant improvement in internal source monitoring tasks (p = 0.001, Cohen's d = 0.97) was observed, but reality monitoring tasks demonstrated moderate improvement (p = 0.02, Cohen's d = 0.44). The study provides insights into the neural mechanisms of source monitoring in healthy individuals and proposes tDCS as a therapeutic intervention, laying the foundation for future studies to refine tDCS protocols and develop individualized approaches to address source monitoring deficits in schizophrenia.
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Affiliation(s)
- Gaurav Sharma
- Department of Physiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Vinay Chitturi
- Department of Physiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Vivek Kumar Sharma
- Department of Physiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Rajesh Kathrotia
- Department of Physiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Pradip Barde
- Department of Physiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Naresh Parmar
- Department of Physiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Medhavi Sharma
- Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Ragini D Singh
- Department of Biochemistry, All India Institute of Medical Sciences, Rajkot, Gujarat, India.
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Ranjan S, Odegaard B. Reality monitoring and metacognitive judgments in a false-memory paradigm. Neurosci Res 2024; 201:3-17. [PMID: 38007192 DOI: 10.1016/j.neures.2023.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 10/19/2023] [Accepted: 11/15/2023] [Indexed: 11/27/2023]
Abstract
How well do we distinguish between different memory sources when the information from imagination and perception is similar? And how do metacognitive (confidence) judgments differ across different sources of experiences? To study these questions, we developed a reality monitoring task using semantically related words from the Deese-Roediger-McDermott (DRM) paradigm of false memories. In an orientation phase, participants either perceived word pairs or had to voluntarily imagine the second word of a word pair. In a test phase, participants viewed words and had to judge whether the paired word was previously perceived, imagined, or new. Results revealed an interaction between memory source and judgment type on both response rates and confidence judgments: reality monitoring was better for new and perceived (compared to imagined) sources, and participants often incorrectly reported imagined experiences to be perceived. Individuals exhibited similar confidence between correct imagined source judgments and incorrect imagined sources reported to be perceived. Modeling results indicated that the observed judgments were likely due to an externalizing bias (i.e., a bias to judge the memory source as perceived). Additionally, we found that overall metacognitive ability was best in the perceived source. Together, these results reveal a source-dependent effect on response rates and confidence ratings, and provide evidence that observers are surprisingly prone to externalizing biases when monitoring their own memories.
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Xiao Y, Nie A. Does Expecting Matter? The Impact of Experimentally Established Expectations on Subsequent Memory Retrieval of Emotional Words. J Intell 2023; 11:130. [PMID: 37504773 PMCID: PMC10381812 DOI: 10.3390/jintelligence11070130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/29/2023] Open
Abstract
Previous studies have confirmed that different degrees of expectation, including the bipolarity of the expected and unexpected, as well as an intermediate level (no expectation), can affect memory. However, only a few investigations have manipulated expectation through experimentally established schema, with no consideration of how expectation impacts both item and source memory. Furthermore, stimulus emotionality may also impact memory. Therefore, we conducted a study to investigate the effects of three levels of expectation on item and source memory while considering the impact of stimulus emotionality. The experiment began with a phase dedicated to learning the rules. In the subsequent study phase, negative and neutral words were manipulated as expected, no expectation, and unexpected, based on these rules. This was followed by tasks focused on item and source memory. The study found that there was a "U-shape" relationship between expectation and item memory. Additionally, the study revealed the distinct impacts of expectation on item and source memory. When it came to item memory, both expected and unexpected words were better remembered than those with no expectations. In source memory, expected words showed memory inferiority for expectation-irrelevant source information, but an advantage for expectation-relevant source information. Stimulus emotionality modulated the effect of expectation on both item and source memory. Our findings provide behavioral evidence for the schema-linked interactions between medial prefrontal and medial temporal regions (SLIMM) theory, which proposes that congruent and incongruent events enhance memory through different brain regions. The different patterns between item and source memory also support dual-process models. Moreover, we speculate that processing events with varying levels of emotionality may undermine the impact of expectation, as implied by other neural investigations.
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Affiliation(s)
- Yueyue Xiao
- Department of Psychology and Behavioral Sciences, Zhejiang University, Hangzhou 310028, China
| | - Aiqing Nie
- Department of Psychology, College of Educational Sciences, Shanxi Normal University, Taiyuan 030031, China
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Shen D, Yao X, Bao D, Yu Y. Content categorization for memory retrieval: A method for evaluating design performance. PLoS One 2023; 18:e0280459. [PMID: 36656842 PMCID: PMC9851509 DOI: 10.1371/journal.pone.0280459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/01/2023] [Indexed: 01/20/2023] Open
Abstract
Designers search for memories and retrieve appropriate mental information during design brainstorming. The specific contents of retrieved memories can serve as stimuli for new ideas, or act as barriers to innovation. These contents can be divided into different categories, which are reflected in designers' creativities, and derived from individual lives and design experiences. Appropriate categorization of retrieved memory exemplars remains a fundamental research issue. This study tentatively divided retrieved memory exemplars into eight categories from brainstorming on the topic of library desk and chair design. A verification questionnaire was performed and validated the accuracy of categorization. The categorization result could be applied to design education in terms of understanding students' design performances and capabilities.
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Affiliation(s)
- Danni Shen
- School of Art and Design, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Xuelin Yao
- School of Art and Design, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Defu Bao
- School of Art and Design, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
- * E-mail: (DB); (YY)
| | - Yuxiang Yu
- School of Art and Design, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
- * E-mail: (DB); (YY)
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Kusztrits I, Marquardt L, Hugdahl K, Hirnstein M. Transcranial direct current stimulation (tDCS) enhances internal source monitoring abilities in healthy participants. PLoS One 2021; 16:e0257010. [PMID: 34529676 PMCID: PMC8445448 DOI: 10.1371/journal.pone.0257010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 08/20/2021] [Indexed: 11/18/2022] Open
Abstract
Source monitoring refers to the ability to identify the origin of a memory, for example, whether you remember saying something or thinking about it, and confusions of these sources have been associated with the experience of auditory verbal hallucinations (AVHs). Both AVHs and source confusions are reported to originate from dysfunctional brain activations in the prefrontal cortex (PFC) and the superior temporal gyrus (STG); specifically, it is assumed that a hypoactive PFC and a hyperactive STG gives rise to AVHs and source confusions. We set out to test this assumption by trying to mimic this hypertemporal/hypofrontal model in healthy individuals with transcranial direct current stimulation (tDCS): the inhibitory cathode was placed over the left PFC and the excitatory anode over the left dorsolateral STG. Participants completed a reality monitoring task (distinguishing between external and internal memory sources) and an internal source monitoring task (distinguishing between two or more internal memory sources) in two separate experiments (offline vs. online tDCS). In the offline experiment (n = 34), both source monitoring tasks were completed after tDCS stimulation, and in the online experiment (n = 27) source monitoring tasks were completed while simultaneously being stimulated with tDCS. We found that internal source monitoring abilities were significantly enhanced during active online tDCS, while reality monitoring abilities were unaffected by stimulation in both experiments. We speculate, based on combining the present findings with previous studies, that there might be different brain areas involved in reality and internal source monitoring. While internal source monitoring seems to involve speech production areas, specifically Broca’s area, as suggested in the present study, reality monitoring seems to rely more on the STG and DLPFC, as shown in other studies of the field.
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Affiliation(s)
- Isabella Kusztrits
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
- NORMENT Norwegian Centre for Mental Health Disorders Research, University of Bergen and Haukeland University Hospital, Bergen, Norway
- * E-mail:
| | - Lynn Marquardt
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
- NORMENT Norwegian Centre for Mental Health Disorders Research, University of Bergen and Haukeland University Hospital, Bergen, Norway
| | - Kenneth Hugdahl
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
- NORMENT Norwegian Centre for Mental Health Disorders Research, University of Bergen and Haukeland University Hospital, Bergen, Norway
- Department of Radiology, Haukeland University Hospital, Bergen, Norway
- Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Marco Hirnstein
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway
- NORMENT Norwegian Centre for Mental Health Disorders Research, University of Bergen and Haukeland University Hospital, Bergen, Norway
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Wang B, Ren Y. Time-dependent effects of discrete post-encoding emotions on item memory and source memory. Memory 2020; 28:417-440. [PMID: 32192395 DOI: 10.1080/09658211.2020.1729384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study examined time-dependent effects of discrete emotions on item and source memory. In Experiment 1, after encoding, participants watched a comic, disgust-inducing, anger-inducing or neutral video at different delays. Positive emotion did not affect item memory but enhanced source memory (only in the 5 min delay). Anger impaired recognition in all delays, but a trend occurred for anger to impair source memory only in the 50 min delay. Disgust did not affect item memory, but a trend emerged for it to enhance and impair source memory in the 5 and 35 min delays, respectively. Experiment 2 showed that positive emotion and disgust had no effect on recognition, and consistent with Experiment 1, positive emotion, not anger or disgust, enhanced source memory. A trend occurred for positive emotion and disgust to impair source memory in the 0 min delay but not in the other delays. Consistent with Experiment 1, Experiment 3 showed that anger impaired both recognition and source memory (for males). Taken together, these findings suggest that the effect of emotion does vary depending on nature of memory tasks, category of emotion, and delay in emotion elicitation.
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Affiliation(s)
- Bo Wang
- Department of Psychology, School of Sociology and Psychology, Central University of Finance and Economics, Beijing, People's Republic of China
| | - Yanju Ren
- School of Psychology, Shandong Normal University, Jinan, People's Republic of China
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