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Neural Correlates of Subliminal Language Processing.

Axelrod V, Bar M, Rees G, Yovel G - Cereb. Cortex (2014)

Bottom Line: The results of several functional magnetic resonance imaging studies have suggested that unconscious lexical and semantic processing is confined to the posterior temporal lobe, without involvement of the frontal lobe-the regions that are indispensable for conscious language processing.We found that subjectively and objectively invisible meaningful sentences and unpronounceable nonwords could be discriminated not only in the left posterior superior temporal sulcus (STS), but critically, also in the left middle frontal gyrus.We conclude that frontal lobes play a role in unconscious language processing and that activation of the frontal lobes per se might not be sufficient for achieving conscious awareness.

View Article: PubMed Central - PubMed

Affiliation: The Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, Israel UCL Institute of Cognitive Neuroscience.

No MeSH data available.


Related in: MedlinePlus

Schematic flow of one block with meaningful sentence in CFS invisible experiment. The words are translated to English for illustrative purpose only while in the experiment all the materials were in Russian. The structure of the blocks with unpronounceable nonwords was the same as the blocks with meaningful sentences, but substituting nonwords (random letter permutations) for words. In the functional localizer (visible experiment) the block flow was similar to that depicted in this figure while the words were visible via both eyes (no CFS mask) and the task was 1-back word repetition (instead of awareness report at the end of the block).
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BHU022F1: Schematic flow of one block with meaningful sentence in CFS invisible experiment. The words are translated to English for illustrative purpose only while in the experiment all the materials were in Russian. The structure of the blocks with unpronounceable nonwords was the same as the blocks with meaningful sentences, but substituting nonwords (random letter permutations) for words. In the functional localizer (visible experiment) the block flow was similar to that depicted in this figure while the words were visible via both eyes (no CFS mask) and the task was 1-back word repetition (instead of awareness report at the end of the block).

Mentions: In the current functional magnetic resonance imaging (MRI) study we explored the neural correlates of subliminal language processing, with a novel design that addresses the concerns reviewed above. Observers were presented with series of consecutively presented textual stimuli: meaningful sentences or unpronounceable nonwords (Fedorenko et al. 2010), which were rendered invisible using continuous flash suppression (CFS) (Tsuchiya and Koch 2005) for extended period of time (10 s) (Fig. 1). Critically, as we sought for evidence of unconscious language processing of any type, we decided to use meaningful sentences that required not only semantic, but also syntactic and structural processing—the design which permitted to increase potential differences between meaningful (sentences) and meaningless (nonwords) conditions. After each block of either sentences or nonwords participants reported whether they had been aware of even a single word—a procedure which ensured that data analyses were conducted only on blocks judged invisible by participants. To discriminate between neural activity elicited by the 2 conditions we used multivoxel pattern classification analyses (MVPA) focusing on the language network (Fedorenko et al. 2010), which was localized on a per-participant basis using the same stimuli while they were fully visible. The principal goal of our research was to test whether the frontal lobes were involved in any unconscious processing of language. The secondary goal was to reveal whether using a paradigm that is different from previous studies and by measuring awareness report after each block, the neural correlates of subliminal processing could still be found in the left posterior temporal lobe. Given that different subliminal paradigms do not always yield similar effects (Almeida et al. 2008, 2013; Kanai et al. 2010; Faivre et al. 2012), such a replication is important for establishing this general cognitive phenomenon.Figure 1.


Neural Correlates of Subliminal Language Processing.

Axelrod V, Bar M, Rees G, Yovel G - Cereb. Cortex (2014)

Schematic flow of one block with meaningful sentence in CFS invisible experiment. The words are translated to English for illustrative purpose only while in the experiment all the materials were in Russian. The structure of the blocks with unpronounceable nonwords was the same as the blocks with meaningful sentences, but substituting nonwords (random letter permutations) for words. In the functional localizer (visible experiment) the block flow was similar to that depicted in this figure while the words were visible via both eyes (no CFS mask) and the task was 1-back word repetition (instead of awareness report at the end of the block).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494027&req=5

BHU022F1: Schematic flow of one block with meaningful sentence in CFS invisible experiment. The words are translated to English for illustrative purpose only while in the experiment all the materials were in Russian. The structure of the blocks with unpronounceable nonwords was the same as the blocks with meaningful sentences, but substituting nonwords (random letter permutations) for words. In the functional localizer (visible experiment) the block flow was similar to that depicted in this figure while the words were visible via both eyes (no CFS mask) and the task was 1-back word repetition (instead of awareness report at the end of the block).
Mentions: In the current functional magnetic resonance imaging (MRI) study we explored the neural correlates of subliminal language processing, with a novel design that addresses the concerns reviewed above. Observers were presented with series of consecutively presented textual stimuli: meaningful sentences or unpronounceable nonwords (Fedorenko et al. 2010), which were rendered invisible using continuous flash suppression (CFS) (Tsuchiya and Koch 2005) for extended period of time (10 s) (Fig. 1). Critically, as we sought for evidence of unconscious language processing of any type, we decided to use meaningful sentences that required not only semantic, but also syntactic and structural processing—the design which permitted to increase potential differences between meaningful (sentences) and meaningless (nonwords) conditions. After each block of either sentences or nonwords participants reported whether they had been aware of even a single word—a procedure which ensured that data analyses were conducted only on blocks judged invisible by participants. To discriminate between neural activity elicited by the 2 conditions we used multivoxel pattern classification analyses (MVPA) focusing on the language network (Fedorenko et al. 2010), which was localized on a per-participant basis using the same stimuli while they were fully visible. The principal goal of our research was to test whether the frontal lobes were involved in any unconscious processing of language. The secondary goal was to reveal whether using a paradigm that is different from previous studies and by measuring awareness report after each block, the neural correlates of subliminal processing could still be found in the left posterior temporal lobe. Given that different subliminal paradigms do not always yield similar effects (Almeida et al. 2008, 2013; Kanai et al. 2010; Faivre et al. 2012), such a replication is important for establishing this general cognitive phenomenon.Figure 1.

Bottom Line: The results of several functional magnetic resonance imaging studies have suggested that unconscious lexical and semantic processing is confined to the posterior temporal lobe, without involvement of the frontal lobe-the regions that are indispensable for conscious language processing.We found that subjectively and objectively invisible meaningful sentences and unpronounceable nonwords could be discriminated not only in the left posterior superior temporal sulcus (STS), but critically, also in the left middle frontal gyrus.We conclude that frontal lobes play a role in unconscious language processing and that activation of the frontal lobes per se might not be sufficient for achieving conscious awareness.

View Article: PubMed Central - PubMed

Affiliation: The Gonda Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, Israel UCL Institute of Cognitive Neuroscience.

No MeSH data available.


Related in: MedlinePlus