- Email: [email protected]
Neural changes in control implementation of a continuous task
Poster Abstracts / Brain and Cognition 67 (2008) S11–S47
neural resources underlying the detection of pitch and vowel deviance are distinct or overlapping. doi:10.1016/j.bandc.2008.02.054
Priming vs. rhyming: Orthographic and phonological activation in the left and right hemispheres Annukka K. Lindell School of Psychology, University of Wales, Bangor, Penrallt Road, Bangor, Gwynedd LL57 2AS, UK E-mail addres: [email protected] The classic ‘verbal/nonverbal’ description of left and right hemisphere function, though a handy rule of thumb, underestimates the right hemisphere’s linguistic capacity. Even though, the right cerebral hemisphere is far from ‘nonverbal’, clinical research suggests that it lacks the capacity to convert orthography to phonology. To evaluate the phonological processing capabilities of the left and right hemispheres in the normal population, participants completed one of two visual half-field tasks: A homophone priming task assessing implicit phonological activation, and a rhyme judgement task assessing explicit recruitment of phonology. In both tasks, the degree of orthographic and phonological overlap between stimulus pairs was manipulated: (a) High orthographic and phonological similarity (not, knot); (b) high orthographic and low phonological similarity (pint, hint); (c) low orthographic and high phonological similarity (use, ewes); or (d) low orthographic and low phonological similarity (kind, done). As anticipated, across explicit and implicit tasks, high orthographic similarity facilitated both left and right hemisphere performance. Critically, for the implicit homophone priming task, only left hemisphere trials benefited when phonological similarity between prime and target was high. As such, the findings indicate that while both hemispheres are capable of orthographic analysis, phonological processing is limited to the left hemisphere. doi:10.1016/j.bandc.2008.02.055
Asymmetries in the spatial coding of numbers in the absence of response conflict Andrea M. Loftus, E.R. Nicholls Michael Department of Psychology, University of Melbourne, Swanston Street, Parkville, Vic. 3010, Australia E-mail address: [email protected] (E.R. Nicholls Michael) The mental representation of numbers along a left-toright oriented number line affects spatial cognition, facilitating responses to numbers located in the ipsilateral hemispace (the spatial–numerical association of response codes
S29
(SNARC) effect). We investigated whether the association between numbers and space occurs at an early-stage-related to sensory representation or at a later, response-related stage. Attentional biases were measured in twenty dextrals using forced-choice luminance discriminations between two mirror-reversed luminance gradients (the greyscales task). The greyscales stimuli were overlayed with strings of: (a) Low numbers, (b) high numbers and (c) neutral characters. Results showed leftward and rightward attentional biases for low and high numbers, respectively. The neutral condition yielded a non-significant leftward bias. Because the response (up/down) was orthogonal to the dimension of interest (left/right), the effect of number magnitude cannot be attributed to late-stage response congruencies. The data demonstrate that shifting the focus of attention along a mental number line affects the perception of stimuli in the left and right hemispaces. doi:10.1016/j.bandc.2008.02.056
Neural changes in control implementation of a continuous task Ovidiu V. Lungu a,b,1, Meagan M. Binenstock c, Megan A. Pline c, Jennifer R. Yeaton c, James R. Carey c a
Brain Sciences Center, VA Medical Center, One Veterans Drive (11B), Minneapolis, MN 55417, USA b Department of Neuroscience, University of Minnesota, 321 Church Street, Minneapolis, MN 55455, USA c Program in Physical Therapy, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA 1 Present address: Centre de recherche de l’IUGM, Room M-6814, 4565 ch. Queen Mary, Montreal, Que., Canada H3W 1W5. E-mail address: [email protected] (O.V. Lungu) It is commonly agreed that control implementation, being a resource-consuming endeavour, is not exerted continuously or in simple tasks. However, most research in the field was done using tasks that varied the need for control on a trial-by-trial basis (e.g. Stroop, flanker), in a discrete fashion. In this case, the anterior cingulate cortex (ACC) was found to monitor the need for control, while regions in prefrontal cortex (PFC) were found to be involved in control implementation. Whether the same control mechanism would be used or not in continuous tasks was an open question. In our study we found that in a continuous task, the same neural substrate subserves control monitoring (ACC), but that the neural substrate of control implementation changes over time. Early in the task, regions in PFC were involved in control implementation, while later the control was taken over by subcortical structures, specifically the caudate. Our results suggest that humans possess a flexible control mechanism, with a specific structure dedicated to monitoring
S30
Poster Abstracts / Brain and Cognition 67 (2008) S11–S47
the need for control, and with multiple structures involved in control implementation. Acknowledgments This work was supported by the National Institutes of Health (National Center for Research Resources #M01RR00400, Biomedical Technology Research Resources #P41-R008079) and Brain Sciences Chair, Department of Veterans Affairs, VA Medical Center, Minneapolis, MN, USA. This research was done while the first author was a postdoctoral fellow at the University of Minnesota. Currently, Ovidiu Lungu is postdoctoral student at Centre de recherche de l’Institut Universitaire de Ge´riatrie de Montre´al of Universite´ de Montre´al. doi:10.1016/j.bandc.2008.02.057
False recognition effect in a matching span task Anne-Laure Mace´, Nicole Caza Centre de recherche, Institut universitaire de ge´riatrie de Montre´al, 4565 chemin Queen Mary, Montre´al, Que., Canada H3W 1W4 De´partement de psychologie, Universite´ de Montre´al, Succursale Centre-ville, Montre´al, Que., Canada H3C 3J7 E-mail-address: [email protected] (A.-L. Mace´) False recognition (FR) of non-studied items is typically observed in long-term memory using lists of associated words. This effect is relevant to distinguish between two approaches to short-term memory (STM). According to language-based models, STM performance depends on all activated linguistic representations (phonological, lexical, and semantic). In matching span of associated words, in which two successive lists are judged to be same or different, the model predicts FR effects are due to spreading activation of lexical/semantic representations. That is, lists will be judged to be similar although a semantically related word (or lure) is introduced in the second list. Redintegration models, however, suggest that lexical/semantic representations may be consulted to support reconstruction of decaying phonological traces in the STM store. Given that the lure is not presented in the first list, and thus cannot decay in STM, this model predicts no FR effect, especially since the task requires no verbal output. The aim of this study was to test these predictions in young participants using matching span. First lists were semantically related to a lure, similar to the DRM procedure, whereas second lists were identical or different from the first list. When different, a lure or unrelated word replaced a word from the first list. An articulatory suppression condition was used to decrease availability of phonological traces. Results showed that
lists containing a lure were more falsely recognized than those with an unrelated word. The finding of a FR effect in matching span supports language-based models of STM. doi:10.1016/j.bandc.2008.02.058
The recognition of frequent suffixes and the parsing of verb roots in 11-month-old infants Alexandra Marquis, Rushen Shi De´partement de Psychologie, Universite´ du Que´bec a` Montre´al, 305 rue Christin, Montre´al, Que., Canada H3C 3P8 E-mail address: [email protected] (A. Marquis) Infants begin analysing distributional patterns of speech by 8–9 months of age. Here we inquire whether infants recognise frequent verb suffixes and use them to parse verb roots. We measured French-learning 11-month-olds’ detection of verb roots using a looking procedure. In Experiment 1, infants heard isolated tokens of an infrequent verb root,/bif/ or/tar/, and were then tested with sentences containing both roots in conjugated forms,/ bife/,/tare/. Results showed a listening preference (longer looking time) while infants heard sentences containing the targets, suggesting that infants parsed both roots. The parsing of/bif/ was particularly complex, involving not only resyllabification, but also the [i]-[I] allophonic alternation in [bIf]-[bife]. Experiment 2 examined if the parsing was indeed due to infants’ recognition of/e/ morpheme. Infants heard the same target roots but then heard sentences containing the roots conjugated with a nonsense morpheme/u/ (i.e.,/bifu/,/taru/). We expected that infants would consider/bifu/,/taru/ as monomorphemic forms and would not extract the unrelated/bif/,/tar/ from the/ u/ context. Indeed, infants who heard the target/bif/ did not prefer /bifu/ sentences, confirming our expectations. Infants exposed to the target/tar/, however, preferred/ taru/ sentences. This response may reflect infants’ recognition of/ta/ (homophonic to the frequent function word ‘‘ta”) in/taru/, rather than the parsing of/tar/. We are conducting additional experiments to explore this question. Taken together, our data provide the first evidence supporting prelinguistic infants’ ability to use suffixes to parse verbal roots. Acknowledgments This research was supported by funding from FQRSC, NSERC and SSHRC to the second author. doi:10.1016/j.bandc.2008.02.059
neural resources underlying the detection of pitch and vowel deviance are distinct or overlapping. doi:10.1016/j.bandc.2008.02.054
Priming vs. rhyming: Orthographic and phonological activation in the left and right hemispheres Annukka K. Lindell School of Psychology, University of Wales, Bangor, Penrallt Road, Bangor, Gwynedd LL57 2AS, UK E-mail addres: [email protected] The classic ‘verbal/nonverbal’ description of left and right hemisphere function, though a handy rule of thumb, underestimates the right hemisphere’s linguistic capacity. Even though, the right cerebral hemisphere is far from ‘nonverbal’, clinical research suggests that it lacks the capacity to convert orthography to phonology. To evaluate the phonological processing capabilities of the left and right hemispheres in the normal population, participants completed one of two visual half-field tasks: A homophone priming task assessing implicit phonological activation, and a rhyme judgement task assessing explicit recruitment of phonology. In both tasks, the degree of orthographic and phonological overlap between stimulus pairs was manipulated: (a) High orthographic and phonological similarity (not, knot); (b) high orthographic and low phonological similarity (pint, hint); (c) low orthographic and high phonological similarity (use, ewes); or (d) low orthographic and low phonological similarity (kind, done). As anticipated, across explicit and implicit tasks, high orthographic similarity facilitated both left and right hemisphere performance. Critically, for the implicit homophone priming task, only left hemisphere trials benefited when phonological similarity between prime and target was high. As such, the findings indicate that while both hemispheres are capable of orthographic analysis, phonological processing is limited to the left hemisphere. doi:10.1016/j.bandc.2008.02.055
Asymmetries in the spatial coding of numbers in the absence of response conflict Andrea M. Loftus, E.R. Nicholls Michael Department of Psychology, University of Melbourne, Swanston Street, Parkville, Vic. 3010, Australia E-mail address: [email protected] (E.R. Nicholls Michael) The mental representation of numbers along a left-toright oriented number line affects spatial cognition, facilitating responses to numbers located in the ipsilateral hemispace (the spatial–numerical association of response codes
S29
(SNARC) effect). We investigated whether the association between numbers and space occurs at an early-stage-related to sensory representation or at a later, response-related stage. Attentional biases were measured in twenty dextrals using forced-choice luminance discriminations between two mirror-reversed luminance gradients (the greyscales task). The greyscales stimuli were overlayed with strings of: (a) Low numbers, (b) high numbers and (c) neutral characters. Results showed leftward and rightward attentional biases for low and high numbers, respectively. The neutral condition yielded a non-significant leftward bias. Because the response (up/down) was orthogonal to the dimension of interest (left/right), the effect of number magnitude cannot be attributed to late-stage response congruencies. The data demonstrate that shifting the focus of attention along a mental number line affects the perception of stimuli in the left and right hemispaces. doi:10.1016/j.bandc.2008.02.056
Neural changes in control implementation of a continuous task Ovidiu V. Lungu a,b,1, Meagan M. Binenstock c, Megan A. Pline c, Jennifer R. Yeaton c, James R. Carey c a
Brain Sciences Center, VA Medical Center, One Veterans Drive (11B), Minneapolis, MN 55417, USA b Department of Neuroscience, University of Minnesota, 321 Church Street, Minneapolis, MN 55455, USA c Program in Physical Therapy, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA 1 Present address: Centre de recherche de l’IUGM, Room M-6814, 4565 ch. Queen Mary, Montreal, Que., Canada H3W 1W5. E-mail address: [email protected] (O.V. Lungu) It is commonly agreed that control implementation, being a resource-consuming endeavour, is not exerted continuously or in simple tasks. However, most research in the field was done using tasks that varied the need for control on a trial-by-trial basis (e.g. Stroop, flanker), in a discrete fashion. In this case, the anterior cingulate cortex (ACC) was found to monitor the need for control, while regions in prefrontal cortex (PFC) were found to be involved in control implementation. Whether the same control mechanism would be used or not in continuous tasks was an open question. In our study we found that in a continuous task, the same neural substrate subserves control monitoring (ACC), but that the neural substrate of control implementation changes over time. Early in the task, regions in PFC were involved in control implementation, while later the control was taken over by subcortical structures, specifically the caudate. Our results suggest that humans possess a flexible control mechanism, with a specific structure dedicated to monitoring
S30
Poster Abstracts / Brain and Cognition 67 (2008) S11–S47
the need for control, and with multiple structures involved in control implementation. Acknowledgments This work was supported by the National Institutes of Health (National Center for Research Resources #M01RR00400, Biomedical Technology Research Resources #P41-R008079) and Brain Sciences Chair, Department of Veterans Affairs, VA Medical Center, Minneapolis, MN, USA. This research was done while the first author was a postdoctoral fellow at the University of Minnesota. Currently, Ovidiu Lungu is postdoctoral student at Centre de recherche de l’Institut Universitaire de Ge´riatrie de Montre´al of Universite´ de Montre´al. doi:10.1016/j.bandc.2008.02.057
False recognition effect in a matching span task Anne-Laure Mace´, Nicole Caza Centre de recherche, Institut universitaire de ge´riatrie de Montre´al, 4565 chemin Queen Mary, Montre´al, Que., Canada H3W 1W4 De´partement de psychologie, Universite´ de Montre´al, Succursale Centre-ville, Montre´al, Que., Canada H3C 3J7 E-mail-address: [email protected] (A.-L. Mace´) False recognition (FR) of non-studied items is typically observed in long-term memory using lists of associated words. This effect is relevant to distinguish between two approaches to short-term memory (STM). According to language-based models, STM performance depends on all activated linguistic representations (phonological, lexical, and semantic). In matching span of associated words, in which two successive lists are judged to be same or different, the model predicts FR effects are due to spreading activation of lexical/semantic representations. That is, lists will be judged to be similar although a semantically related word (or lure) is introduced in the second list. Redintegration models, however, suggest that lexical/semantic representations may be consulted to support reconstruction of decaying phonological traces in the STM store. Given that the lure is not presented in the first list, and thus cannot decay in STM, this model predicts no FR effect, especially since the task requires no verbal output. The aim of this study was to test these predictions in young participants using matching span. First lists were semantically related to a lure, similar to the DRM procedure, whereas second lists were identical or different from the first list. When different, a lure or unrelated word replaced a word from the first list. An articulatory suppression condition was used to decrease availability of phonological traces. Results showed that
lists containing a lure were more falsely recognized than those with an unrelated word. The finding of a FR effect in matching span supports language-based models of STM. doi:10.1016/j.bandc.2008.02.058
The recognition of frequent suffixes and the parsing of verb roots in 11-month-old infants Alexandra Marquis, Rushen Shi De´partement de Psychologie, Universite´ du Que´bec a` Montre´al, 305 rue Christin, Montre´al, Que., Canada H3C 3P8 E-mail address: [email protected] (A. Marquis) Infants begin analysing distributional patterns of speech by 8–9 months of age. Here we inquire whether infants recognise frequent verb suffixes and use them to parse verb roots. We measured French-learning 11-month-olds’ detection of verb roots using a looking procedure. In Experiment 1, infants heard isolated tokens of an infrequent verb root,/bif/ or/tar/, and were then tested with sentences containing both roots in conjugated forms,/ bife/,/tare/. Results showed a listening preference (longer looking time) while infants heard sentences containing the targets, suggesting that infants parsed both roots. The parsing of/bif/ was particularly complex, involving not only resyllabification, but also the [i]-[I] allophonic alternation in [bIf]-[bife]. Experiment 2 examined if the parsing was indeed due to infants’ recognition of/e/ morpheme. Infants heard the same target roots but then heard sentences containing the roots conjugated with a nonsense morpheme/u/ (i.e.,/bifu/,/taru/). We expected that infants would consider/bifu/,/taru/ as monomorphemic forms and would not extract the unrelated/bif/,/tar/ from the/ u/ context. Indeed, infants who heard the target/bif/ did not prefer /bifu/ sentences, confirming our expectations. Infants exposed to the target/tar/, however, preferred/ taru/ sentences. This response may reflect infants’ recognition of/ta/ (homophonic to the frequent function word ‘‘ta”) in/taru/, rather than the parsing of/tar/. We are conducting additional experiments to explore this question. Taken together, our data provide the first evidence supporting prelinguistic infants’ ability to use suffixes to parse verbal roots. Acknowledgments This research was supported by funding from FQRSC, NSERC and SSHRC to the second author. doi:10.1016/j.bandc.2008.02.059