Motivation enhances visual working memory capacity through the modulation of central cognitive processes

摘要: Abstract Motivationiswellknowntoenhanceworkingmemory(WM)capacity,butthemechanismunderlyingthiseffectremainsunclear.TheWMprocesscanbedividedintoencoding,maintenance,andretrieval,andinachangedetectionvisualWMparadigm,theencodingandretrievalprocessescanbesubdividedintoperceptualandcentralprocessing.Toclarifywhichof these segments are most influenced by motivation, we measured ERPs in a change detection task with differentialmonetary rewards. The results showed that the enhancement of WM capacity under high motivation was accompaniedby modulations late central components but not those reflecting attentional control on perceptual inputs across allstagesofWM.Weconcludethatthe“state-dependent”shiftofmotivationimpactedthecentral,ratherthantheperceptualfunctions order to achieve better behavioral performances. Descriptors: Working memory , Motivation ERPMotivation (i.e., reward-related status) is known enhanceworkingmemory(WM)capacity(GilbertFKrawczyk,Gazzaley, & D’Esposito, 2007; Watanabe et al., 2001). Convergingevidencesuggeststhatthiseffectresultsfromtheinteractionoftwobrain networks (Hikosaka Watanabe, 2000). Firstly, lateral pre-frontal regions, including dorsolateral prefrontal cortex(DLPFC), involved executive functions general butespecially processing (Goldman-Rakic, 1995). Secondly, theventromedial area cortex (VMPFC) encodes themotivational significance current situation (e.g., rewardvalue) (Kringelbach Rolls, 2004). Electrophysiological studiesusingmacaquemonkeyshavesuggestedinteractionsbetweentheseareas, indicating some activities DLPFC also reflectedthe reward level (Leon Shadlen, 1999) and VMPFCpotentially transmitted information theDLPFC (Wallis Miller, 2003). Neuroimaging studies have alsosupported this hypothesis (Gilbert Fiez, 2004; Pochon al.,2002; Szatkowska, Bogorodzki, Wolak, Marchewka, S Vogel Machizawa,2004), participants required encode to-be-rememberedstimuli (memory array) compare them to-be-matchedstimuli (test presented after retention time, judgewhether stimuli same. encoding-maintenanceprocess during comprises to-be-remembered as well store them. In asimilar way, retrieval process involves input thetest array items thememory representations. This four-way distinction provides aframework for assessing locus motivational influences onworking memory.Recent progress visual working (VWM) researchoffers us useful indices investigate mechanisms. anERP component contralateral delay activity (CDA) wasfound be neural correlate VWM encoding mainte-nance processes (McCollough, Machizawa, Vogel, Vogel& It observed difference waveform attemporo-occipital cortical areas, which more negatively chargedat than ipsilateral electrodes rememberedhemifield. persists maintenance delay, and,importantly, amplitude CDA corresponds numberof remembered, reaching an asymptotic limit ateach individual’s estimated (approximately 3 or 4objects). Thus, CDAamplitude believed reflect number ofrepresentationsmaintainedinVWM(Ikkai,McCollough,&Vogel,2010).