Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations?
Any thought, whether it refers to the present moment or reflects an imagination, is again encoded as a new memory trace. Orbitofrontal reality filtering (ORFi) denotes an on-line mechanism which verifies whether upcoming thoughts relate to ongoing reality or not. Its failure induces reality confusio...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2017-11-01
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| Series: | Frontiers in Behavioral Neuroscience |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fnbeh.2017.00216/full |
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| author | Raphaël Thézé Aurélie L. Manuel Louis Nahum Adrian G. Guggisberg Armin Schnider |
| author_facet | Raphaël Thézé Aurélie L. Manuel Louis Nahum Adrian G. Guggisberg Armin Schnider |
| author_sort | Raphaël Thézé |
| collection | DOAJ |
| description | Any thought, whether it refers to the present moment or reflects an imagination, is again encoded as a new memory trace. Orbitofrontal reality filtering (ORFi) denotes an on-line mechanism which verifies whether upcoming thoughts relate to ongoing reality or not. Its failure induces reality confusion with confabulations and disorientation. If the result of this process were simultaneously encoded, it would easily explain later distinction between memories relating to a past reality and memories relating to imagination, a faculty called reality monitoring. How the brain makes this distinction is unknown but much research suggests that it depends on processes active when information is encoded. Here we explored the precise timing between ORFi and encoding as well as interactions between the involved brain structures. We used high-density evoked potentials and two runs of a continuous recognition task (CRT) combining the challenges of ORFi and encoding. ORFi was measured by the ability to realize that stimuli appearing in the second run had not appeared in this run yet. Encoding was measured with immediately repeated stimuli, which has been previously shown to induce a signal emanating from the medial temporal lobe (MTL), which has a protective effect on the memory trace. We found that encoding, as measured with this task, sets in at about 210 ms after stimulus presentation, 35 ms before ORFi. Both processes end at about 330 ms. Both were characterized by increased coherence in the theta band in the MTL during encoding and in the orbitofrontal cortex (OFC) during ORFi. The study suggests a complex interaction between OFC and MTL allowing for thoughts to be re-encoded while they undergo ORFi. The combined influence of these two processes at 200–300 ms may leave a memory trace that allows for later effortless reality monitoring in most everyday situations. |
| first_indexed | 2024-04-14T00:55:51Z |
| format | Article |
| id | doaj.art-d6d975851dbb487fb5142462607beee1 |
| institution | Directory Open Access Journal |
| issn | 1662-5153 |
| language | English |
| last_indexed | 2024-04-14T00:55:51Z |
| publishDate | 2017-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Behavioral Neuroscience |
| spelling | doaj.art-d6d975851dbb487fb5142462607beee12022-12-22T02:21:38ZengFrontiers Media S.A.Frontiers in Behavioral Neuroscience1662-51532017-11-011110.3389/fnbeh.2017.00216273323Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations?Raphaël Thézé0Aurélie L. Manuel1Louis Nahum2Adrian G. Guggisberg3Armin Schnider4aboratory of Cognitive Neurorehabilitation, Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, Geneva, Switzerlandaboratory of Cognitive Neurorehabilitation, Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, Geneva, Switzerlandaboratory of Cognitive Neurorehabilitation, Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, Geneva, Switzerlandaboratory of Cognitive Neurorehabilitation, Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, Geneva, Switzerlandaboratory of Cognitive Neurorehabilitation, Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, Geneva, SwitzerlandAny thought, whether it refers to the present moment or reflects an imagination, is again encoded as a new memory trace. Orbitofrontal reality filtering (ORFi) denotes an on-line mechanism which verifies whether upcoming thoughts relate to ongoing reality or not. Its failure induces reality confusion with confabulations and disorientation. If the result of this process were simultaneously encoded, it would easily explain later distinction between memories relating to a past reality and memories relating to imagination, a faculty called reality monitoring. How the brain makes this distinction is unknown but much research suggests that it depends on processes active when information is encoded. Here we explored the precise timing between ORFi and encoding as well as interactions between the involved brain structures. We used high-density evoked potentials and two runs of a continuous recognition task (CRT) combining the challenges of ORFi and encoding. ORFi was measured by the ability to realize that stimuli appearing in the second run had not appeared in this run yet. Encoding was measured with immediately repeated stimuli, which has been previously shown to induce a signal emanating from the medial temporal lobe (MTL), which has a protective effect on the memory trace. We found that encoding, as measured with this task, sets in at about 210 ms after stimulus presentation, 35 ms before ORFi. Both processes end at about 330 ms. Both were characterized by increased coherence in the theta band in the MTL during encoding and in the orbitofrontal cortex (OFC) during ORFi. The study suggests a complex interaction between OFC and MTL allowing for thoughts to be re-encoded while they undergo ORFi. The combined influence of these two processes at 200–300 ms may leave a memory trace that allows for later effortless reality monitoring in most everyday situations.http://journal.frontiersin.org/article/10.3389/fnbeh.2017.00216/fullsource memoryevoked potentialsconnectivitytheta bandorbitofrontal cortexreality monitoring |
| spellingShingle | Raphaël Thézé Aurélie L. Manuel Louis Nahum Adrian G. Guggisberg Armin Schnider Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations? Frontiers in Behavioral Neuroscience source memory evoked potentials connectivity theta band orbitofrontal cortex reality monitoring |
| title | Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations? |
| title_full | Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations? |
| title_fullStr | Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations? |
| title_full_unstemmed | Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations? |
| title_short | Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations? |
| title_sort | simultaneous reality filtering and encoding of thoughts the substrate for distinguishing between memories of real events and imaginations |
| topic | source memory evoked potentials connectivity theta band orbitofrontal cortex reality monitoring |
| url | http://journal.frontiersin.org/article/10.3389/fnbeh.2017.00216/full |
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