Differences in auditory processing of words and pseudowords: An fMRI study

Abstract

Abstract:Although there has been great interest in the neuroanatomical basis of reading, little attention has been focused on auditory language processing. The purpose of this study was to examine the differential neuroanatomical response to the auditory processing of real words and pseudowords. Eight healthy right-handed participants performed two phoneme monitoring tasks (one with real word stimuli and one with pseudowords) during a functional magnetic resonance imaging (fMRI) scan with a 4.1 T system. Both tasks activated the inferior frontal gyrus (IFG), the posterior superior temporal gyrus (pSTG) and the inferior parietal lobe (IPL). Pseudoword processing elicited significantly more activation within the posterior cortical regions compared with real word processing. Previous reading studies have suggested that this increase is due to an increased demand on the lexical access system. The left inferior frontal gyrus, on the other hand, did not reveal a significant difference in the amount of activation as a function of stimulus type. The lack of a differential response in IFG for auditory processing supports its hypothesized involvement in grapheme to phoneme conversion processes. These results are consistent with those from previous neuroimaging reading studies and emphasize the utility of examining both input modalities (e.g., visual or auditory) to compose a more complete picture of the language network.

An Event-Related fMRI Investigation of Implicit Semantic Priming

“…In contrast, Newman and Tweig (2001) showed greater activation for nonwords than for words in the posterior STG and the inferior parietal regions. These results are in conflict with the current findings that showed similar activation maps for the unrelated and nonword conditions, and significantly greater activation for words than for nonwords in the left MTG, the left anterior cingulate, and the left precuneus.…”

“…These differences have been attributed largely to processes of grapheme-to-phoneme conversion (Price, 1998;Herbster et al, 1997;Rumsey et al, 1997). Only a few studies have investigated auditory word and nonword processing (Newman & Tweig, 2001;Binder et al, 1994). Although all of these studies have found that words and pseudowords activate similar neural systems, a number of them have found no significant differences in the amount of activation between words and pseudowords (Hirano et al, 1997;Binder et al, 1994;Wise et al, 1991).…”

Interactions of the hippocampal system and the prefrontal cortex in learning language-like rules

“…In particular, neuroimaging studies (von Zerssen et al, 2001; Wiggs et al, 1999) and studies with patients suffering from retrosplenial amnesia (von Cramon and Schuri, 1992) point to a specific role of this area in integrating various aspects of episodic information rather than in storage of episodic memories. The lateral temporal lobes, also demonstrating decreased activity, are thought to be engaged in lexical-semantic processing (Kotz et al, 1999;Newman and Twieg, 2001). Because the vocabulary of BROCANTO is composed of pronounceable items that, however, do not exist either in German or any other natural language known to the participants, this could lead to an activation of the lateral temporal lobes during the initial stage of learning (Newman and Twieg, 2001).…”

“…The lateral temporal lobes, also demonstrating decreased activity, are thought to be engaged in lexical-semantic processing (Kotz et al, 1999;Newman and Twieg, 2001). Because the vocabulary of BROCANTO is composed of pronounceable items that, however, do not exist either in German or any other natural language known to the participants, this could lead to an activation of the lateral temporal lobes during the initial stage of learning (Newman and Twieg, 2001). The rapid decrease of activity in these regions may be interpreted as the system's reaction to the irrelevance of lexical-semantic aspects in the present study.…”

Modulation of the Lexical–Semantic Network by Auditory Semantic Priming: An Event-Related Functional MRI Study

“…The inferolateral frontal area has been consistently found to be more active in the case of pseudowords, but only with visual presentation. In the case of auditory presentation, the increase in brain activity associated with pseudoword processing has been suggested to affect the posterior temporoparietal areas (Newman and Twieg, 2001). …”