Vzdrževanje posameznih lastnosti in integriranih informacij v vidno-prostorskem delovnem spominu

Slana Ozimič, Anka (author), Repovš, Grega (mentor)

Namen doktorske naloge je bil preučiti mehanizme vzdrževanja posameznih lastnosti in integriranih informacij v vidno-prostorskem delovnem spominu. Oblikovali smo model delovnega spomina, ki je temeljil na predpostavki, da pri vzdrževanju informacij v vidno-prostorskem delovnem spominu sodelujeta dva sistema, tj. hemisferno specifičen reprezentacijski sistem, ki omogoča vzpostavljanje reprezentacij relevantnih informacij, in aktivacijski sistem, ki omogoča aktivno vzdrževanje vzpostavljenih reprezentacij. Na podlagi modela smo oblikovali tri raziskovalna vprašanja, na katera smo odgovorili v treh ločenih študijah. V prvi smo preverjali, ali je omejena kapaciteta vidnega delovnega spomina odraz omejene kapacitete tako reprezentacijskega kot aktivacijskega sistema. V drugi smo preverjali obstoj neodvisnih reprezentacijskih in aktivacijskih sistemov znotraj vidnega delovnega spomina. V tretji smo obravnavali mehanizme vzdrževanja integriranih vidnih in prostorskih reprezentacij. Rezultati prve študije so pokazali, da je kapaciteta za vzdrževanje orientacij objektov omejena tako s kapaciteto reprezentacijskih podsistemov obeh hemisfer kot tudi s kapaciteto aktivacijskega sistema ter da se kapaciteti obeh sistemov skozi življenjska obdobja spreminjata zelo podobno. V drugi študiji smo pri preverjanju kapacitete vzdrževanja barv in oblik replicirali spoznanja prve študije ter jih nadgradili z ugotovitvijo, da ima delovni spomin za barve in oblike skupen reprezentacijski sistem ter neodvisna aktivacijska sistema. Rezultati tretje študije so pokazali, da integracija informacij o barvi in položaju ne temelji na dodatnem, za integracijo specifičnem sistemu, temveč na povezanem delovanju širokega nabora možganskih področij, ki vključujejo tako področja, ki se prednostno odzivajo tako na barve in položaje kot tudi druga modalno nespecifična področja. Pridobljeni rezultati naslavljajo pomembna teoretična vprašanja, vezana na mehanizme vzdrževanja informacij v vidno-prostorskem delovnem spominu in vlogo reprezentacijskih in aktivacijskih podsistemov, ter razkrivajo kompleksno delovanje sistema vidno-prostorskega delovnega spomina.

• Language: Slovenian
• Keywords: vidno-prostorski delovni spomin, kapaciteta, aktivno vzdrževanje, reprezentacije, obojestranska prednost, integracija
• Work type: Doctoral dissertation
• Organization: MF - Faculty of Medicine
• Year: 2020
• PID: 20.500.12556/RUL-117341
• COBISS.SI-ID: 23786499
• Publication date in RUL: 08.07.2020

Secondary language

• Language: English
• Title: Maintenance of individual features and integrated information in visuo-spatial working memory

Abstract

The aim of the doctoral thesis was to study the mechanisms of the maintenance of individual features and integrated information in visual-spatial working memory. We designed a working memory model based on the assumption that two systems are involved in the maintenance of information in visual-spatial working memory, i.e. a hemisphere-specific representational system that enables the formation of the representations of relevant information, and an active maintenance system that enables active maintenance of the established representations. Based on the model, we formulated three research questions, which we addressed in three separate studies. In the first we examined whether the capacity of visual working memory is limited both by the representational and active maintenance systems. In the second, we explored whether independent representational and/or active maintenance systems support maintenance of colors and shapes in the visual working memory. In the third, we studied the mechanisms for maintenance of integrated visual and spatial representations. The results of the first study showed that the capacity for maintaining objects’ orientations is limited by the capacity of the representational subsystems of both hemispheres, as well as the capacity of the active maintenance system, and that the capacities of the two systems change very similarly throughout the lifespan. In the second study, we replicated the findings of the first study for maintenance of colors and shapes, and found that the working memory for colors and shapes has a common representational system and independent active maintenance systems. The results of the third study revealed that the integration of color and position is not based on an additional, integration-specific system, but rather on the coordinated operation of a widespread network of brain regions, including regions that preferentially respond to colors and positions as well as other modality non-specific regions. The obtained results address important theoretical issues related to the mechanisms of information maintenance in visual-spatial working memory and the role of representational and active maintenance subsystems, and reveal the complex functioning of the visual-spatial working memory system.

• Keywords: visual-spatial working memory, capacity, active maintenance, representations, bilateral field advantage, integration