Biomedical subjects

Ron Borowsky

Publications and source records attributed to Ron Borowsky.

10 recordsLinked to original sources

PubMed2006

FMRI of ventral and dorsal processing streams in basic reading processes: insular sensitivity to phonology.

Most current models of the neurophysiology of basic reading processes agree on a system involving two cortical streams: a ventral stream (occipital-temporal) used when accessing familiar words encoded in lexical memory, and a dorsal stream (occipital-parietal-frontal) used when phonetically decoding words (i.e., mapping sublexical spelling onto sounds). The models diverge, however, on the issue of whether the insular cortex is involved. The present fMRI study required participants to read aloud exception words (e.g., 'one', which must be read via lexical memory) and pseudohomophones (e.g., 'wun', which must be read via sublexical spelling to sound translation) to examine the processing streams as well as the insular cortex, and their relationship to lexical and sublexical reading processes. The present study supports the notion of independent ventral-lexical and dorsal-sublexical streams, and further suggests the insular cortex to be sensitive to phonological processing (particularly sublexical spelling-sound translation). These latter findings illuminate the nature of insular activity during reading, which must be explored further in future studies, and accounted for in models of the neurophysiology of reading.

Adult↗

PubMed2006

Parallel distributed processing and lexical-semantic effects in visual word recognition: are a few stages necessary?

D. C. Plaut and J. R. Booth (2000) presented a parallel distributed processing model that purports to simulate human lexical decision performance. This model (and D. C. Plaut, 1995) offers a single mechanism account of the pattern of factor effects on reaction time (RT) between semantic priming, word frequency, and stimulus quality without requiring a stages-of-processing account of additive effects. Three problems are discussed. First, no evidence is provided that this model can discriminate between words and nonwords with the same orthographic structure and still produce the pattern of factor effects on RT it currently claims to produce. Second, the level of representation used by the model to make a lexical decision is inconsistent with what is known about how skilled readers with damage to their semantic system make word/nonword discriminations. Finally, there are a number of results that are difficult to reconcile with the single mechanism account. The authors' preference is to retain the stages-of-processing account.

Humans↗

PubMed2005

Modularity and intersection of "what", "where" and "how" processing of visual stimuli: a new method of FMRI localization.

Research on the modularity of perceptual and cognitive processes has often pointed to a ventral-dorsal distinction in cortical pathways that depend upon the nature of the stimuli and the task. However, it is not clear whether the dorsal, occipital-parietal stream specializes in locating visual objects (i.e., a "where" stream), or taking action toward objects (i.e., a "how" stream), although there is some consensus for a ventral, occipital-temporal "what" stream that specializes in the identification of visual objects. It is also not clear to what extent word and picture processing are modular along these streams, as functional imaging maps to date have not addressed the modularity question directly. Here we present two types of functional imaging maps that directly show modularity and intersection of processing function for word and picture stimuli in tasks that require decisions about "what is", "where is", or "how do you interact with" a stimulus (N=6 participants). Our results reveal a middle dorsal "how" stream with some modular regions of activation that are distinct from activation during "where" processing, and that words and pictures involve several modular regions of activation along these streams.

Adult↗

PubMed2005

Process dissociation of sight vocabulary and phonetic decoding in reading: a new perspective on surface and phonological dyslexias.

Recent research on developmental dyslexia has suggested a phonological core deficit hypothesis (e.g., Manis, Seidenberg, Doi, McBride-Chang, & Peterson, 1996; Stanovich, Siegel, & Gottardo, 1997) whereby pure cases of developmental phonological dyslexia (dysfunctional phonetic decoding processing but normal sight vocabulary processing) can exist, but pure cases of developmental surface dyslexia (dysfunctional sight vocabulary processing but normal phonetic decoding processing) should not. By applying Jacoby's (1991) and Lindsay and Jacoby's (1994) process dissociation procedure to the reading of regular and exception words, we present a method that serves to estimate readers' reliance on sight vocabulary and phonetic decoding during real word recognition. These reliance estimates are then used in Castles and Coltheart's (1993) regression-based approach to identify normal readers and developmental dyslexics. This new method: (1) allows one to explore normal reading acquisition and both the delay and deviance accounts of developmental dyslexia, (2) provides an alternative to matching dyslexics to both chronological-age and reading-age control groups, and (3) uses only real words. We present evidence that pure cases of developmental surface dyslexia can be obtained with both Castles and Coltheart's measure as well as our own, and that developmental surface dyslexia is not simply a delayed reading deficit. The theoretical importance and utility of estimates of reliance on sight vocabulary and phonetic decoding is discussed.

Child↗

PubMed2005

Neuroimaging of language processes: fMRI of silent and overt lexical processing and the promise of multiple process imaging in single brain studies.

OBJECTIVE: To implement and evaluate a multiple-process functional magnetic resonance imaging (fMRI) paradigm designed to effectively and efficiently activate several language-related regions for use with neurosurgical patients. Both overt and covert response conditions were examined. METHODS: The fMRI experiments compared the traditional silent word-generation condition versus an overt one as they engage frontal language regions (Experiment 1) and silent versus overt semantic association conditions as they engage multiple language processing regions (Experiment 2). RESULTS: In Experiment 1, the overt condition yielded greater magnitude of activation, but not volume of activation, in the left inferior frontal and insular cortices than did the silent condition for most, but not all, participants. Experiment 2 demonstrated that the activation of multiple established language processing regions (ie, orthographic, phonological, and semantic) can be achieved in a significant number of participants, particularly under overt semantic association conditions and that such activation varies in predictable ways. CONCLUSION: The traditional silent response condition cannot be considered as equivalent to the overt response condition during word generation or semantic association. The multiple-process imaging method introduced here was sensitive to processing robust orthographic, phonological, and semantic regions, particularly under the overt response condition.

Brain Mapping↗

PubMed2003

Examining the interactivity of lexical orthographic and phonological processing.

The number and type of connections involving different levels of orthographic and phonological representations differentiate between several models of spoken and visual word recognition. At the sublexical level of processing, Borowsky, Owen, and Fonos (1999) demonstrated evidence for direct processing connections from grapheme representations to phoneme representations (i.e., a sensitivity effect) over and above any bias effects, but not in the reverse direction. Neural network models of visual word recognition implement an orthography to phonology processing route that involves the same connections for processing sublexical and lexical information, and thus a similar pattern of cross-modal effects for lexical stimuli are expected by models that implement this single type of connection (i.e., orthographic lexical processing should directly affect phonological lexical processing, but not in the reverse direction). Furthermore, several models of spoken word perception predict that there should be no direct connections between orthographic representations and phonological representations, regardless of whether the connections are sublexical or lexical. The present experiments examined these predictions by measuring the influence of a cross-modal word context on word target discrimination. The results provide constraints on the types of connections that can exist between orthographic lexical representations and phonological lexical representations.

Attention↗

PubMed2002

The role of the left hemisphere in motor control of touch: a functional magnetic resonance imaging analysis.

Previous research using a simple finger-touching task has shown greater blood oxygenation level dependent (BOLD) activation volume in the motor cortex of the right hemisphere for contralateral finger touching compared to ipsilateral finger touching, but no significant contralateral advantage for the left hemisphere. Such equal involvement of the left hemisphere for both contralateral and ipsilateral finger touching suggests a special role of the left hemisphere for finger touching. In contrast, we found a contralateral advantage in the motor cortex of both hemispheres in a majority of participants (14/16) when consistently activated BOLD volumes were examined. However, participants who did not show a clear contralateral advantage for the left hemisphere did show activation in the left inferior frontal gyrus (IFG; Broca's Area) and in the left insular cortex, which suggests that verbally mediated sequencing of finger movements can account for our less frequent result.

Brain↗

PubMed2002

Diagnostics of phonological lexical processing: pseudohomophone naming advantages, disadvantages, and base-word frequency effects.

Phonological lexical access has been investigated by examining both a pseudohomophone (e.g., brane) base-word frequency effect and a pseudohomophone advantage over pronounceable nonwords (e.g., frane) in a single mixed block of naming trials. With a new set of pseudohomophones and non-words presented in a mixed block, we replicated the standard finding in the naming literature: no reliable base-word frequency effect, and apseudohomophone advantage. However, for this and two of three other sets of stimuli--those of McCann and Besner (1987), Seidenberg, Petersen, MacDonald, and Plaut (1996), and Herdman, LeFevre, and Greenham (1996), respectively--reliable effects of base-word frequency on pseudohomophone naming latency were found when pseudohomophones were presented in pure blocks prior to nonwords. Three of the four stimulus sets tested produced a pseudohomophone naming disadvantage when pseudohomophones were presented prior to nonwords. When nonwords were presented first, these effects were diminished. A strategy-based scaling account of the data is argued to provide a better explanation of the data than is the criterion-homogenization theory (Lupker, Brown, & Colombo, 1997).

Humans↗

PubMedDate not supplied

FMRI of two measures of phonological processing in visual word recognition: ecological validity matters.

Previous functional magnetic resonance imaging (fMRI) studies have investigated the role of phonological processing by utilizing nonword rhyming decision tasks (e.g., Pugh et al., 1996). Although such tasks clearly engage phonological components of visual word recognition, it is clear that decision tasks are more cognitively involved than the simple overt naming tasks, which more closely map onto normal reading behavior. Our research aim for this study was to examine the advantages of overt naming tasks for fMRI studies of word recognition processes. Process models are presented to highlight the similarities and differences between two cognitive tasks that are used in the word recognition literature, pseudohomophone naming (e.g., pronounce BRANE) and rhyming decision (e.g., do LEAT and JEAT rhyme?). An fMRI study identified several differences in cortical activation associated with the differences observed in the process models. Specifically, the results show that the overt naming task involved the insular cortex and inferior frontal gyrus, whereas the rhyming decision task engaged the temporal-parietal regions. It is argued that future fMRI research examining the neuroanatomical components of basic visual word recognition utilize overt naming tasks.

Decision Making↗

PubMedDate not supplied

What does rapid automatized naming measure? A new RAN task compared to naming and lexical decision.

The present research investigated the relationship between Rapid Automatized Naming (RAN) performance, letter-string reading measures of sight vocabulary (SV) and phonetic decoding (PD), and lexical decision. Criterion-based naming rates were obtained from three types of RAN tasks: digits, letters, and letter sounds. Latency measures were obtained from the naming of regular words, exception words, nonwords and pseudohomophones; as well as button press and verbal lexical decision tasks. Regression analyses supported the hypotheses that RAN-Letters latency reflects SV processing in that its variance is uniquely accounted for by exception word naming latency and button press lexical decision latency, and that RAN-Letter Sounds latency best reflects PD processing in that its variance is uniquely accounted for by pseudohomophone and nonword naming latency. Findings are discussed in light of what the RAN tasks are measuring, implications involving visual word recognition models of reading, and the utility of the new RAN-Letter Sounds task with respect to diagnostic and remediation applications.

Humans↗