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Separating lexical-semantic access from other mnemonic processes in picture-name verification.

Smith JF, Braun AR, Alexander GE, Chen K, Horwitz B - Front Psychol (2013)

Bottom Line: Contrasts between sessions identified left angular gyrus and middle temporal gyrus as key additional players in the naming network.Left inferior frontal regions participated in both naming and non-linguistic AV memory suggesting the region is responsible for AV memory independent of phonological content contrary to previous proposals.Functional connectivity between angular gyrus and left inferior frontal gyrus and left middle temporal gyrus increased when performing the AV task as naming.

View Article: PubMed Central - PubMed

Affiliation: Brain Imaging and Modeling Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda, MD, USA.

ABSTRACT
We present a novel paradigm to identify shared and unique brain regions underlying non-semantic, non-phonological, abstract, audio-visual (AV) memory vs. naming using a longitudinal functional magnetic resonance imaging experiment. Participants were trained to associate novel AV stimulus pairs containing hidden linguistic content. Half of the stimulus pairs were distorted images of animals and sine-wave speech versions of the animal's name. Images and sounds were distorted in such a way as to make their linguistic content easily recognizable only after being made aware of its existence. Memory for the pairings was tested by presenting an AV pair and asking participants to verify if the two stimuli formed a learned pairing. After memory testing, the hidden linguistic content was revealed and participants were tested again on their recollection of the pairings in this linguistically informed state. Once informed, the AV verification task could be performed by naming the picture. There was substantial overlap between the regions involved in recognition of non-linguistic sensory memory and naming, suggesting a strong relation between them. Contrasts between sessions identified left angular gyrus and middle temporal gyrus as key additional players in the naming network. Left inferior frontal regions participated in both naming and non-linguistic AV memory suggesting the region is responsible for AV memory independent of phonological content contrary to previous proposals. Functional connectivity between angular gyrus and left inferior frontal gyrus and left middle temporal gyrus increased when performing the AV task as naming. The results are consistent with the hypothesis that, at the spatial resolution of fMRI, the regions that facilitate non-linguistic AV associations are a subset of those that facilitate naming though reorganized into distinct networks.

No MeSH data available.


Related in: MedlinePlus

Language related changes in functional connectivity with the angular gyrus. Shown are areas with reliably greater BOLD signal relative to baseline for the Uninformed, non-linguistic session that nonetheless had reliably greater functional connectivity with the angular gyrus during the Informed, linguistic session. (A). The Delay period portion of the task. (B). The Auditory target portion of the task.
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Figure 4: Language related changes in functional connectivity with the angular gyrus. Shown are areas with reliably greater BOLD signal relative to baseline for the Uninformed, non-linguistic session that nonetheless had reliably greater functional connectivity with the angular gyrus during the Informed, linguistic session. (A). The Delay period portion of the task. (B). The Auditory target portion of the task.

Mentions: A voxel [−48, −58, 42] in the vicinity of the AG was selected from the peak of the univariate analysis during the delay period. This voxel has a 60% probability of being in the AG (PGa) and a 40% probability of lying in area PFm; the transition between the angular and supramarginal gyri (Caspers et al., 2006, 2008). Using a paired t-test, the regression slope for correct animal/name trials was compared between the Informed and Uninformed sessions to identify regions more connected to the AG during the Informed condition. The search was restricted to only those regions with reliably increased BOLD signal during the Uninformed sessions. The results are shown in Figure 4A for the delay portion of the task. During the delay period, several foci active in the Uninformed session in the left middle and superior temporal gyri, left IFG, and bilateral supplementary motor cortex were more connected to the left AG in the Informed session than in the Uninformed session. Similar increases in connectivity, though smaller is spatial extent, were seen during the auditory target portion of the task (Figure 4B).


Separating lexical-semantic access from other mnemonic processes in picture-name verification.

Smith JF, Braun AR, Alexander GE, Chen K, Horwitz B - Front Psychol (2013)

Language related changes in functional connectivity with the angular gyrus. Shown are areas with reliably greater BOLD signal relative to baseline for the Uninformed, non-linguistic session that nonetheless had reliably greater functional connectivity with the angular gyrus during the Informed, linguistic session. (A). The Delay period portion of the task. (B). The Auditory target portion of the task.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3795327&req=5

Figure 4: Language related changes in functional connectivity with the angular gyrus. Shown are areas with reliably greater BOLD signal relative to baseline for the Uninformed, non-linguistic session that nonetheless had reliably greater functional connectivity with the angular gyrus during the Informed, linguistic session. (A). The Delay period portion of the task. (B). The Auditory target portion of the task.
Mentions: A voxel [−48, −58, 42] in the vicinity of the AG was selected from the peak of the univariate analysis during the delay period. This voxel has a 60% probability of being in the AG (PGa) and a 40% probability of lying in area PFm; the transition between the angular and supramarginal gyri (Caspers et al., 2006, 2008). Using a paired t-test, the regression slope for correct animal/name trials was compared between the Informed and Uninformed sessions to identify regions more connected to the AG during the Informed condition. The search was restricted to only those regions with reliably increased BOLD signal during the Uninformed sessions. The results are shown in Figure 4A for the delay portion of the task. During the delay period, several foci active in the Uninformed session in the left middle and superior temporal gyri, left IFG, and bilateral supplementary motor cortex were more connected to the left AG in the Informed session than in the Uninformed session. Similar increases in connectivity, though smaller is spatial extent, were seen during the auditory target portion of the task (Figure 4B).

Bottom Line: Contrasts between sessions identified left angular gyrus and middle temporal gyrus as key additional players in the naming network.Left inferior frontal regions participated in both naming and non-linguistic AV memory suggesting the region is responsible for AV memory independent of phonological content contrary to previous proposals.Functional connectivity between angular gyrus and left inferior frontal gyrus and left middle temporal gyrus increased when performing the AV task as naming.

View Article: PubMed Central - PubMed

Affiliation: Brain Imaging and Modeling Section, National Institute on Deafness and Other Communication Disorders, National Institutes of Health Bethesda, MD, USA.

ABSTRACT
We present a novel paradigm to identify shared and unique brain regions underlying non-semantic, non-phonological, abstract, audio-visual (AV) memory vs. naming using a longitudinal functional magnetic resonance imaging experiment. Participants were trained to associate novel AV stimulus pairs containing hidden linguistic content. Half of the stimulus pairs were distorted images of animals and sine-wave speech versions of the animal's name. Images and sounds were distorted in such a way as to make their linguistic content easily recognizable only after being made aware of its existence. Memory for the pairings was tested by presenting an AV pair and asking participants to verify if the two stimuli formed a learned pairing. After memory testing, the hidden linguistic content was revealed and participants were tested again on their recollection of the pairings in this linguistically informed state. Once informed, the AV verification task could be performed by naming the picture. There was substantial overlap between the regions involved in recognition of non-linguistic sensory memory and naming, suggesting a strong relation between them. Contrasts between sessions identified left angular gyrus and middle temporal gyrus as key additional players in the naming network. Left inferior frontal regions participated in both naming and non-linguistic AV memory suggesting the region is responsible for AV memory independent of phonological content contrary to previous proposals. Functional connectivity between angular gyrus and left inferior frontal gyrus and left middle temporal gyrus increased when performing the AV task as naming. The results are consistent with the hypothesis that, at the spatial resolution of fMRI, the regions that facilitate non-linguistic AV associations are a subset of those that facilitate naming though reorganized into distinct networks.

No MeSH data available.


Related in: MedlinePlus