Broca's area, sentence comprehension, and working memory: an fMRI study

“…reduced digit and sentence working memory spans, and their sentence comprehension in high load situations has been correlated with verbal working memory capacity more broadly defi ned (Daneman and Carpenter, 1980; De Renzi and Nichelli, 1975; Just and Carpenter, 1992; Swinney and Taylor, 1971).”

“…reduced digit and sentence working memory spans, and their sentence comprehension in high load situations has been correlated with verbal working memory capacity more broadly defi ned (Daneman and Carpenter, 1980; De Renzi and Nichelli, 1975; Just and Carpenter, 1992; Swinney and Taylor, 1971).”

“MRIcro (Rorden and Brett, 2000) was used to reconstruct the highresolution structural image, and an in-house Matlab program was used to reconstruct the echo-planar images.”

“Some of the evidence supporting the involvement of the phonological loop in sentence comprehension has emerged from reading comprehension and short-term memory studies involving concurrent task paradigms (e.g. Baddeley, 1981; Baddeley et al., 1975; Besner and Davelaar, 1982; Coltheart, 1993).”

“Imaging studies of verbal working memory have regularly implicated Broca’s area as part of the phonological loop, particularly in the articulatory rehearsal component (Smith et al., 1998; Zatorre et al., 1992).”

“…gyrus, i.e. the pars triangularis and pars opercularis) has been implicated in syntactic processing (Bradley et al., 1980; Caramazza and Zurif, 1976; Grodzinsky, 1984, 2000), but also has been proposed as a verbal working memory resource for sentence comprehension (Caplan and Waters, 1999; Just…”

“…including Broca’s area: some patients with inferior frontal damage have more diffi culty comprehending semantically reversible objectrelative clause sentences than semantically reversible subjectrelative clause sentences or active-voice sentences (Bradley et al., 1980; Caramazza and Zurif, 1976).”

“…processing implicated Broca’s area, particularly in the comprehension of complex structures (Caplan et al., 1998, 1999; Dapretto and Bookheimer, 1999; Just et al., 1996; Stromswold et al., 1996), other studies found a lack of correspondence between sentence processing and activity in Broca’s area.”

“We then calculated corresponding a′ statistics, which provide an estimate of proportion correct corrected for response bias (Grier, 1971).”

“Also, this result provides indirect evidence that Broca’s area is contributing to sentence processing via articulatory rehearsal as previous studies have found that portions of Broca’s area support both speech articulation (including during articulatory rehearsal) (Buchsbaum et al., 2001; Hickok et al., 2003; Jonides…”

“The neural basis of the comprehension pattern often found in Broca’s aphasia is less than clear (Dronkers et al., 2004).”

“Also, this result provides indirect evidence that Broca’s area is contributing to sentence processing via articulatory rehearsal as previous studies have found that portions of Broca’s area support both speech articulation (including during articulatory rehearsal) (Buchsbaum et al., 2001; Hickok et al., 2003; Jonides…”

“In contrast, another region, the anterior temporal lobe, does appear to track with the presence of syntactic structure, and consequently has emerged as a candidate for supporting syntactic and/or compositional semantic processing (Humphries et al., 2001, 2005; Mazoyer et al., 1993; Rogalsky and Hickok, 2008; Vandenber…”

“…processing implicated Broca’s area, particularly in the comprehension of complex structures (Caplan et al., 1998, 1999; Dapretto and Bookheimer, 1999; Just et al., 1996; Stromswold et al., 1996), other studies found a lack of correspondence between sentence processing and activity in Broca’s area.”

“…pars triangularis) for processing syntactically grammaticality judgments of sentences, even if they are unable to comprehend these same sentences (Linebarger et al., 1983; Wulfeck, 1988), suggesting that these patients have signifi - cant syntactic knowledge available to them (Linebarger, 1990;…”

“Also, this result provides indirect evidence that Broca’s area is contributing to sentence processing via articulatory rehearsal as previous studies have found that portions of Broca’s area support both speech articulation (including during articulatory rehearsal) (Buchsbaum et al., 2001; Hickok et al., 2003; Jonides…”

“These authors further point out that evaluating various thematic role possibilities is similar to another proposed function of the inferior frontal gyrus, namely selecting a response from a set of alternatives (Kan and ThompsonSchill, 2004; Novick et al., 2005).”

“…imaging studies of sentence processing implicated Broca’s area, particularly in the comprehension of complex structures (Caplan et al., 1998, 1999; Dapretto and Bookheimer, 1999; Just et al., 1996; Stromswold et al., 1996), other studies found a lack of correspondence between sentence processing…”

“…that inferior frontal regions, including the pars triangularis, demonstrate an increase in activity when subjects observe or imagine performing goal-directed movement sequences, detect musical sequences, or process sequences of events (Koelsch et al., 2002; Schubotz and von Cramon, 2002, 2004).”

“Also, this result provides indirect evidence that Broca’s area is contributing to sentence processing via articulatory rehearsal as previous studies have found that portions of Broca’s area support both speech articulation (including during articulatory rehearsal) (Buchsbaum et al., 2001; Hickok et al., 2003; Jonides…”

“In contrast, another region, the anterior temporal lobe, does appear to track with the presence of syntactic structure, and consequently has emerged as a candidate for supporting syntactic and/or compositional semantic processing (Humphries et al., 2001, 2005; Mazoyer et al., 1993; Rogalsky and Hickok, 2008; Vandenber…”

“…reduced digit and sentence working memory spans, and their sentence comprehension in high load situations has been correlated with verbal working memory capacity more broadly defi ned (Daneman and Carpenter, 1980; De Renzi and Nichelli, 1975; Just and Carpenter, 1992; Swinney and Taylor, 1971).”

“Consistent with previous research (e.g. Caplan et al., 2000, 2008; Fiebach et al., 2005; Stromswold et al., 1996), in the baseline condition, we found a “sentence complexity effect” (greater activation for sentences with object relatives than subject relatives) in Broca’s area (pars opercularis and…”

“…temporal lobe, does appear to track with the presence of syntactic structure, and consequently has emerged as a candidate for supporting syntactic and/or compositional semantic processing (Humphries et al., 2001, 2005; Mazoyer et al., 1993; Rogalsky and Hickok, 2008; Vandenberge et al., 2002).”

“…of the earliest functional imaging studies of sentence processing implicated Broca’s area, particularly in the comprehension of complex structures (Caplan et al., 1998, 1999; Dapretto and Bookheimer, 1999; Just et al., 1996; Stromswold et al., 1996), other studies found a lack of correspondence…”

“…lack of an interference effect for passive voice sentences in our study is consistent with lesion data suggesting that performance on passive sentences is often better than that for object relative clauses sentences, despite the fact that both involve non-canonical word order (Berndt et al., 1996).”

“…of the earliest functional imaging studies of sentence processing implicated Broca’s area, particularly in the comprehension of complex structures (Caplan et al., 1998, 1999; Dapretto and Bookheimer, 1999; Just et al., 1996; Stromswold et al., 1996), other studies found a lack of correspondence…”

“…of the earliest functional imaging studies of sentence processing implicated Broca’s area, particularly in the comprehension of complex structures (Caplan et al., 1998, 1999; Dapretto and Bookheimer, 1999; Just et al., 1996; Stromswold et al., 1996), other studies found a lack of correspondence…”

“Broca’s area was fi rst thought to support syntactic processing because Broca’s aphasics were found to have agrammatic production (Gleason et al., 1975; Goodglass, 1968, 1976; Goodglass and Berko, 1960; Kean, 1977).”

“…gyrus, i.e. the pars triangularis and pars opercularis) has been implicated in syntactic processing (Bradley et al., 1980; Caramazza and Zurif, 1976; Grodzinsky, 1984, 2000), but also has been proposed as a verbal working memory resource for sentence comprehension (Caplan and Waters, 1999; Just…”

“…temporal lobe, does appear to track with the presence of syntactic structure, and consequently has emerged as a candidate for supporting syntactic and/or compositional semantic processing (Humphries et al., 2001, 2005; Mazoyer et al., 1993; Rogalsky and Hickok, 2008; Vandenberge et al., 2002).”

“In contrast, another region, the anterior temporal lobe, does appear to track with the presence of syntactic structure, and consequently has emerged as a candidate for supporting syntactic and/or compositional semantic processing (Humphries et al., 2001, 2005; Mazoyer et al., 1993; Rogalsky and Hickok, 2008; Vandenber…”

“Frontiers in Human Neuroscience | October 2008 | Volume 2 | Article 14 2 in reading comprehension during concurrent articulation compared to concurrent tapping (De Beni et al., 2005; Slowiaczek and Clifton, 1980; Takahashi, 2007).”

“Some of the evidence supporting the involvement of the phonological loop in sentence comprehension has emerged from reading comprehension and short-term memory studies involving concurrent task paradigms (e.g. Baddeley, 1981; Baddeley et al., 1975; Besner and Davelaar, 1982; Coltheart, 1993).”

“, 1980; Caramazza and Zurif, 1976; Grodzinsky, 1984, 2000), but also has been proposed as a verbal working memory resource for sentence comprehension (Caplan and Waters, 1999; Just and Carpenter, 1992; Martin, 2003).”

“Some of the evidence supporting the involvement of the phonological loop in sentence comprehension has emerged from reading comprehension and short-term memory studies involving concurrent task paradigms (e.g. Baddeley, 1981; Baddeley et al., 1975; Besner and Davelaar, 1982; Coltheart, 1993).”

“Also, this result provides indirect evidence that Broca’s area is contributing to sentence processing via articulatory rehearsal as previous studies have found that portions of Broca’s area support both speech articulation (including during articulatory rehearsal) (Buchsbaum et al., 2001; Hickok et al., 2003; Jonides…”

“For example, some patients demonstrate normal comprehension of complex sentences, despite signifi cantly restricted working memory capacities (Caplan and Waters, 1999; Hanten and Martin, 2000; Waters et al., 1991).”

“Frontiers in Human Neuroscience | October 2008 | Volume 2 | Article 14 2 in reading comprehension during concurrent articulation compared to concurrent tapping (De Beni et al., 2005; Slowiaczek and Clifton, 1980; Takahashi, 2007).”

“For example, some patients demonstrate normal comprehension of complex sentences, despite signifi cantly restricted working memory capacities (Caplan and Waters, 1999; Hanten and Martin, 2000; Waters et al., 1991).”

“Broca’s area was fi rst thought to support syntactic processing because Broca’s aphasics were found to have agrammatic production(1) (Gleason et al., 1975; Goodglass, 1968, 1976; Goodglass and Berko, 1960; Kean, 1977).”

“Some of the evidence supporting the involvement of the phonological loop in sentence comprehension has emerged from reading comprehension and short-term memory studies involving concurrent task paradigms (e.g. Baddeley, 1981; Baddeley et al., 1975; Besner and Davelaar, 1982; Coltheart, 1993).”

“Caplan et al. (2008) suggest that the left IFG, generally, supports sentence processing via two possible functions: rehearsal and thematic role checking (i.e. evaluating various thematic role assignment possibilities).”

“…processing syntactically grammaticality judgments of sentences, even if they are unable to comprehend these same sentences (Linebarger et al., 1983; Wulfeck, 1988), suggesting that these patients have signifi - cant syntactic knowledge available to them (Linebarger, 1990; Linebarger et al., 1983;…”

“Figure 1 | Schematic of behavioral task paradigm with SOAP stimuli (Love and Oster, 2002).”

“In addition, irrelevant sounds and speech presented during reading comprehension tasks do not impair reading comprehension as concurrent articulation does (Boyle and Coltheart, 1996).”

“…area support both speech articulation (including during articulatory rehearsal) (Buchsbaum et al., 2001; Hickok et al., 2003; Jonides et al., 1997; Postle et al., 2001; Smith and Jonides, 1997; Smith et al., 1998) and the processing of high-load sentences relative to lower-load sentences…”

“…reduced digit and sentence working memory spans, and their sentence comprehension in high load situations has been correlated with verbal working memory capacity more broadly defi ned (Daneman and Carpenter, 1980; De Renzi and Nichelli, 1975; Just and Carpenter, 1992; Swinney and Taylor, 1971).”

“In addition, patients with lesions to this region have signifi cant defi cits in sequence prediction tasks compared to identifi cation tasks, and compared to patients with prefrontal or parietal lesions (Schubotz et al., 2004).”

“Broca’s area was fi rst thought to support syntactic processing because Broca’s aphasics were found to have agrammatic production1 (Gleason et al., 1975; Goodglass, 1968, 1976; Goodglass and Berko, 1960; Kean, 1977).”

“Such patients typically produce syntactically simple sentences that lack function words and infl ections (Kean, 1995), suggesting that they are lacking the ability to form syntactic structures.”

“…is greater for implausible sentences include the following: (a) activation in the left premotor cortex reflects covert articulatory processing (Rogalsky et al., 2008; Iacoboni, 2008; Callan et al., 2010; Osnes et al., 2011; Adank and Devlin, 2010; Meister et al., 2007; Scott et al., 2009a;…”

“At the next level, the claim is that Broca’s region supports verbal working memory (235) and that this is why this region shows activation when processing syntactically complex sentences (37, 220).”

“In this study, the previously observed sentence complexity effect (greater activation for syntactically more complex sentences relative to less complex sentences) was eliminated in the posterior portion of Broca’s region (pars opercularis, ∼BA 44) when subjects comprehended sentences while they concurrently rehearsed…”

“However, activation during processing of syntactically complex sentences was also assigned to area 45 (triangular part) in studies using semantic plausibility judgment tasks or sentence picture-matching tasks [22,23].”

“Similarly, following activations around Broca’s area in simple articulatory tasks [106], some have argued that activations during language comprehension tasks reflect the need to engage articulatory rehearsal mechanisms [107].”

“Several paradigms were developed for the tasks including: • Syntax and grammar tasks for the Broca region (Rogalsky et al. 2008).”

“The paradigms included • Syntax and grammar tasks for the Broca area (Grossman and Rhee 2001; Nixon et al. 2004; Rogalsky et al. 2008) • Comprehension of lexical meaning and categorization tasks for the Wernicke area (Grossman et al. 2002; Harpaz et al. 2009).”

“A structural violation could trigger working memory processes (Rogalsky et al., 2008) or so-called “cognitive control” processes (Novick et al.”

“On the other hand, this pattern of activity is somewhat consistent with the expectations of a brain area involved in verbal working memory, as previous authors have suggested (Rogalsky et al., 2008; reviewed in detail in Rogalsky & Hickok, 2011).”

“Broca’s area, located in the left frontal part of the temporal lobe, involves sentence comprehension in articulatory rehearsal (109) whereas Wernicke’s area, located in the left frontal and left posterior part of the temporal lobe, processes lexical meanings of words (110).”

“2008) and concurrent comprehension and articulation tasks (Rogalsky et al., 2008) .”

“A number of studies exist on the role of Broca’s area beyond expressive language [54,55], for an overview we refer to Burns et al.”

“In conjunction with rTMS cortical stimulation, the patients performed the following tasks: syntax and grammar tasks designed to engage the Broca Region (Rogalsky et al. 2008); comprehension of lexical meaning and categorization tasks targeting the Wernicke Region (Harpaz et al.”

“In contrast to the above evidence that rehearsal and ordering are conceptually and neurally distinct, Rogalsky et al. (2008) report a decline in sentence processing performance under conditions of articulatory rehearsal.”

“…(Unification) processes in multiple domains of language and cognition (Hagoort 2005; Hagoort 2013; Hagoort 2019; Jackendoff and Audring 2020); in processing complex syntax (Friederici 2012); or in sentence processing due to its role in working memory (Matchin, 2018; Rogalsky et al. 2008).”

“As mentioned in the Introduction, a possible resolution of this paradox comes from hypotheses that Broca’s area supports performance on sentence comprehension tasks through more general cognitive functions such as working memory (Pettigrew & Hillis, 2014; Rogalsky et al., 2008; Kaan & Swaab, 2002; Just et al., 1996) a…”

“Still, it is noteworthy that studies which aimed to isolate the cortical effects of syntactic movement (e.g. Rogalsky et al., 2008; Santi & Grodzinsky, 2007, 2010) have found activations in more anterior portions of the IFG, i.e. in pars triangularis, whereas in our study (as well as in several…”

“The implication of Broca's area might be due to increased complexity of stimuli and increased working memory demands (see Paulesu et al., 1993; Cohen et al., 1997; Rogalsky et al., 2008), since the semantic computation at the end of the sentence requires integration of all previously encountered information, and the t…”

“We did find activations to the ART condition in the more posterior and inferior parts of the LIFG (pars opercularis, frontal operculum) that are also reported for syntactic complexity effects (Fiebach et al., 2005; Friederici et al., 2006b; Rogalsky et al., 2008) and we agree with the conclusions of Rogalsky et al.”

“The left frontal regions (and in particular, the left pars opercularis), which receive many terminations from both the left AF and left SLF-III, have also been associated with various language and speech functions (Long et al., 2016; Rogalsky et al., 2008).”

“However, in contrast to other studies that found activation in BA 44 for syntactic complexity in adults (Bornkessel et al., 2005; Friederici et al., 2006; Rogalsky et al., 2008), the activation in the present study was observed in BA 45.”

“…of this hypothesis, α spectral power has been shown to be inversely correlated with the fMRI BOLD signal (Laufs et al., 2003; Brookes et al., 2005; Scheeringa et al., 2009; Mayhew et al., 2013), leading to the interpretation of α ERS and ERD as indices of cortical inhibition and disinhibition,…”

“However, if PreCG subserves articulatory rehearsal, this would imply specificity in this region for working memory of speech sounds (although others have speculated that LIFG subserves this role, Awh et al., 1996; Paulesu et al., 1993; Rogalsky et al., 2008).”

“An experiment with virtually the same 2 2 design was carried out by Rogalsky et al. (2008).”

“However, we do note that more superior regions in or near the posterior middle frontal cortex have emerged in some neuroimaging studies of syntactic processing, in both production and comprehension (Fedorenko et al., 2012; Matchin and Hickok, 2016; Rogalsky et al., 2008).”

“The individual subject analyses contradict our previous group-level observation that subvocal articulation can explain sentence activations in the PO (Rogalsky et al., 2008).”

“2000; Goucha and Friederici 2015; Zaccarella and Friederici 2015), but other studies reveal that both regions reliably exhibit these effects (Ben-Shachar et al. 2003, 2004; Bornkessel et al. 2005; Rogalsky et al. 2008; Obleser et al. 2011; Pallier et al. 2011; Fedorenko et al. 2012b; Matchin et al. 2017).”

“We conclude by indicating how this multifunctional view of brain-language relations extends to the realm of language recovery from aphasia, where evidence of the influence of nonlinguistic factors on the reshaping of neural circuitry for aphasia rehabilitation is clearly emerging.”

“Cerebral ROIs were chosen a priori based on the sentence comprehension literature (Barch et al., 2013; Binder et al., 2011; Booth et al., 2007; Fengler et al., 2016; Friederici, 2002; Friederici et al., 2003; Keller et al., 2001; Kieren & Buckner, 2009; Rogalsky et al., 2008).”

“…one hand, some studies have concluded that Broca ’ s area is involved in language processing via its contribution to working memory (Nee et al., 2013; Rogalsky et al., 2008; Fiebach et al., 2005; Smith, Jonides, & Koeppe, 1996) or via complex interactions between syntactic and working memory…”

“Furthermore, some of the subregions have also been implicated in domain-general cognitive functions such as strategic retrieval, attentional control, working memory and selection between competing alternatives (Novick et al., 2005; Hampshire and Owen, 2006; Rogalsky et al., 2008).”

“The former two are likely critical regions for verbal WM (Deschamps et al. 2014; Rogalsky et al. 2008); that is, they have been proposed to constitute the phonological loop component of the Baddeley model.”

“, reduced capacities) in these cognitive resources, particularly verbal working memory: individuals with and without aphasia who have reduced verbal working memory capacities demonstrate poorer noncanonical sentence comprehension abilities, but canonical sentence comprehension is largely unaffected1 (e.g., Just & Carp…”

“Some would argue that this linear effect of distance in Broca’s are is related to a phonological working memory (Rogalsky et al., 2008) rather than syntactic/semantic similarity.”

“This suggests that this activation reflects the contribution of working memory resources or cognitive control mechanisms needed to parse difficult input rather than fundamental syntactic operations (Novick et al., 2005; Rogalsky et al., 2008).”

“Functional magnetic resonance imaging (fMRI) studies also found increased activity during filler-gap dependency formation (Fiebach et al., 2005; Kim et al., 2009; Kinno et al., 2008; Rogalsky et al., 2008; Rogalsky et al., 2015; Santi & Grodzinsky, 2007, 2010).”

“An increase in activity as a function of syntactic complexity in Broca's area has been demonstrated in an fMRI study (Rogalsky, Matchin, & Hickok, 2008 ).”

“A previous study of ours directly assessed the role of production-related processes in driving activations in Broca's area during the performance of a complex sentence comprehension task, semantic plausibility judgment (Rogalsky, Matchin, & Hickok, 2008 ).”

“Temporal Processing • Attending to rapid or brief auditory stimuli (e.g., phoneme level) [136,137] Perceptual Processing”

“It has often been suggested that Broca’s area plays a role in sentence processing restricted to working memory and/or production and cognitive control resources that assist sentence processing in difficult circumstances but are not critical for basic combinatorial processing (Matchin, 2018; Rogalsky & Hickok, 2011; Ja…”

“Third, complex noncanonical structures critically involve substantial working memory resources (King & Just, 1991; Pettigrew & Hillis, 2014; Rogalsky et al., 2008), which could be the source of the associations with frontal networks as noted.”

“39,40 The volumes of interest were the anterior temporal lobe (–41, –15, –31), the inferior frontal gyrus (–48, 22, 20), the posterior medial temporal gyrus (–54, –42, 4), and the angular gyrus (–48, –64, 34), as shown in Figure 1.”

“This possibility is compatible with the hypothesis that the LIFG is a working-memory-relevant brain region (Barde, Schwartz, & Thompson-Schill, 2006; Cohen et al., 1997; Paulesu, Frith, & Frackowiak, 1993; Rogalsky et al., 2008).”

“…linking LIFG instead to working memory (Caplan et al., 2000, 2008; Fiebach et al., 2005; Fiebach, Schlesewsky, & Friederici, 2001; Kaan & Swaab, 2002; Rogalsky et al., 2008) or cognitive control (Botvinick, Braver, Barch, Carter, & Cohen, 2001; Miller & Cohen, 2001; Novick, Trueswell, &…”

“10-15 By other models, the left pIFG does not play a critical role during syntactic comprehension but rather performs general top-down cognitive supervisory functions that are non-syntax specific.”

“In both comprehension and production, complex sentences require more processing capacity (Ferreira, 1991; Gibson, 1998) and their processing may be affected by the concurrent task (Klaus et al., 2017; Rogalsky et al., 2008).”

“…or working memory demands in production, which have been hypothesized to be related to LIFG activity (Acheson & MacDonald, 2009; Matchin, 2018; Rogalsky et al., 2008), since production is in itself a “ task, ” while comprehension, as manipulated in the current study, was a more passive…”

“…the psycholinguistic processes associated that decouple structure-building from structural memory and structural prediction, such as a morphosyntactic loop or language-specific working memory (Matchin & Hickok, 2020; Rogalsky, Matchin, & Hickok, 2008; Fiebach et al., 2004; Caplan & Waters, 1999).”

“Moreover, the extent to which the function of LpIFG is specific to syntax or domain-general cognitive mechanisms (such as working memory) remains controversial (Grodzinsky & Santi, 2008; Kaan & Swaab, 2002; Makuuchi et al., 2009; Makuuchi et al., 2013; Rogalsky et al., 2008).”

“Other non-syntactic proposals for the role of the IFG in sentence production include domain-general cognitive control (Assem et al., 2022), phonological short-term memory (Rogalsky et al., 2008; Ivanova et al., 2018; Matchin, 2018), and lexical selection (Novick et al., 2010; Conner et al., 2019).”

“Evidence for this hypothesis comes from neuroimaging studies showing that some areas in the LIFC are activated by both syntactic demands and STM (Matchin et al., 2017; Rogalsky & Hickok, 2011; Rogalsky et al., 2008).”

“In the same vein, Rogalsky, Matchin, and Hickok (2008) have found articulatory rehearsal to interfere with the processing of English object-relative clauses (although in this case the interaction between subvocal rehearsal and the processing of object-relative clauses was found over the pars…”

“The exact nature(s) of the role(s) of Broca’s area in sentence comprehension remains highly debated, with prominent hypotheses suggesting syntactic-specific processes (Grodzinsky, 2000; Grodzinsky and Santi, 2008), verbal working memory (Just et al., 1996; Kaan and Swaab, 2002; Rogalsky et al., 2008; Pettigrew and Hil…”