Formation, even at these low level perceptual representations. Together, these studies provide Aprotinin biological activity strong evidence that, at least under some circumstances, higher level information within our internal representations of context can lead to the preactivation of incoming information at multiple lower level representations. This is important because it implies that there are no hard architectural or neuroanatomical constraints on the flow of activity activated by our internal representation of context on the processing of new bottom-up inputs. However, it is important to recognize that, just because we can use information in a context to pre-activate multiple types of information, this doesn’t necessarily mean that we will do so in every situation. Indeed, as we discuss below, several factors have been shown to influence both the degree and the SC144 chemical information representational level at which upcoming information is predictively pre-activated. Factors influencing predictive pre-activation–The first important factor known to influence predictive pre-activation is the constraint of the context. As discussed above, DeLong et al. (2005) provided evidence that, following highly lexically constraining contexts like (2), predictive pre-activation of the semantic, phonological, and orthographic features of “kite” could modulate the ERP waveform, both before and as the critical word, “kite”, was actually presented. Importantly, these ERP effects were inversely proportional to the lexical constraint of the context, providing strong evidence that lexical constraint of a context can influence the degree of pre-activation.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptLang Cogn Neurosci. Author manuscript; available in PMC 2017 January 01.Kuperberg and JaegerPageIn addition to influencing the degree of pre-activation, there is also evidence that contextual constraint can influence the representational level of predictive pre-activation. Highly lexically constraining contexts can influence the very early stages of processing incoming words, suggesting that they can be used to pre-activate information at sublexical levels of representation (see Staub, 2015, for a recent review of the behavioral eye-tracking literature), with evidence from ERP and MEG studies for facilitation on early ERP components (prior to the N400) that reflect phonological (Brothers, Swaab, Traxler, 2015; Connolly Phillips, 1994; Groppe et al., 2010), orthographic (Federmeier, Mai, Kutas, 2005; Kim Lai, 2012; Lau et al., 2013), or even early perceptual (Dikker Pylkk en, 2011) processing. Contexts that are less lexically constraining, however, do not appear to modulate these early ERP components, even when they facilitate semantic processing, as reflected by modulation within the N400 time window (e.g. Dikker Pylkk en, 2011; Paczynski Kuperberg, 2012, see also Lau et al., 2013). Most empirical work has focused on the effects of lexical constraint, as operationalized using cloze procedures (see footnote 1 in section 1). Contexts that are lexically constraining, by definition, constrain strongly for multiple types of representation at the same time (semantic, phonological and syntactic). It is important to recognize however, that a context can constrain strongly for just one type of upcoming representation, leading just to facilitation of incoming information at this representational level, independently of any other. For example, a discourse context can constrain stro.Formation, even at these low level perceptual representations. Together, these studies provide strong evidence that, at least under some circumstances, higher level information within our internal representations of context can lead to the preactivation of incoming information at multiple lower level representations. This is important because it implies that there are no hard architectural or neuroanatomical constraints on the flow of activity activated by our internal representation of context on the processing of new bottom-up inputs. However, it is important to recognize that, just because we can use information in a context to pre-activate multiple types of information, this doesn’t necessarily mean that we will do so in every situation. Indeed, as we discuss below, several factors have been shown to influence both the degree and the representational level at which upcoming information is predictively pre-activated. Factors influencing predictive pre-activation–The first important factor known to influence predictive pre-activation is the constraint of the context. As discussed above, DeLong et al. (2005) provided evidence that, following highly lexically constraining contexts like (2), predictive pre-activation of the semantic, phonological, and orthographic features of “kite” could modulate the ERP waveform, both before and as the critical word, “kite”, was actually presented. Importantly, these ERP effects were inversely proportional to the lexical constraint of the context, providing strong evidence that lexical constraint of a context can influence the degree of pre-activation.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptLang Cogn Neurosci. Author manuscript; available in PMC 2017 January 01.Kuperberg and JaegerPageIn addition to influencing the degree of pre-activation, there is also evidence that contextual constraint can influence the representational level of predictive pre-activation. Highly lexically constraining contexts can influence the very early stages of processing incoming words, suggesting that they can be used to pre-activate information at sublexical levels of representation (see Staub, 2015, for a recent review of the behavioral eye-tracking literature), with evidence from ERP and MEG studies for facilitation on early ERP components (prior to the N400) that reflect phonological (Brothers, Swaab, Traxler, 2015; Connolly Phillips, 1994; Groppe et al., 2010), orthographic (Federmeier, Mai, Kutas, 2005; Kim Lai, 2012; Lau et al., 2013), or even early perceptual (Dikker Pylkk en, 2011) processing. Contexts that are less lexically constraining, however, do not appear to modulate these early ERP components, even when they facilitate semantic processing, as reflected by modulation within the N400 time window (e.g. Dikker Pylkk en, 2011; Paczynski Kuperberg, 2012, see also Lau et al., 2013). Most empirical work has focused on the effects of lexical constraint, as operationalized using cloze procedures (see footnote 1 in section 1). Contexts that are lexically constraining, by definition, constrain strongly for multiple types of representation at the same time (semantic, phonological and syntactic). It is important to recognize however, that a context can constrain strongly for just one type of upcoming representation, leading just to facilitation of incoming information at this representational level, independently of any other. For example, a discourse context can constrain stro.
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