Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013;8(4):e60377.
doi: 10.1371/journal.pone.0060377. Epub 2013 Apr 2.

Detecting semantic priming at the single-trial level

Jeroen Geuze  1 , Marcel A J van Gerven, Jason Farquhar, Peter Desain
Affiliations

Detecting semantic priming at the single-trial level

Jeroen Geuze et al. PLoS One. 2013.

Abstract

Semantic priming is usually studied by examining ERPs over many trials and subjects. This article aims at detecting semantic priming at the single-trial level. By using machine learning techniques it is possible to analyse and classify short traces of brain activity, which could, for example, be used to build a Brain Computer Interface (BCI). This article describes an experiment where subjects were presented with word pairs and asked to decide whether the words were related or not. A classifier was trained to determine whether the subjects judged words as related or unrelated based on one second of EEG data. The results show that the classifier accuracy when training per subject varies between 54% and 67%, and is significantly above chance level for all subjects (N = 12) and the accuracy when training over subjects varies between 51% and 63%, and is significantly above chance level for 11 subjects, pointing to a general effect.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Histogram of perceived relation between word pairs of both sets.
The 5-point scale on degree of relatedness is on the x-axis and the number of responses per pre-determined category, related (black) versus unrelated (red), is on the y-axis.
Figure 2
Figure 2. Schematic overview the experimental design.
From global in time (top), to local in time (bottom).
Figure 3
Figure 3. Grand average results for the negative component.
Left panel: A topographic representation of the negative component between 330–600 ms. The marked channels show a significant difference between related and unrelated probe responses. Right panel: ERP waveforms for channel Cz for related (black, dashed) and unrelated (red, solid). The area around each line represents the standard deviation, corrected for a within subject design (, p. 361–366). Channel Cz has been chosen as an example channel, as other significant channels are similar. Areas marked in grey show a significant difference.
Figure 4
Figure 4. Classification accuracies for the individually trained classifier and the classifier trained across subjects.
Accuracies are mean accuracies of test set performance over ten folds. (* 0.001
See this image and copyright information in PMC

References

    1. Meyer DE, Schvaneveldt RW (1971) Facilitation in recognizing pairs of words: evidence of a dependence between retrieval operations. Journal of Experimental Psychology 90: 227–234. - PubMed
    1. Kutas M, Hillyard SA (1984) Brain potentials during reading reect word expectancy and semantic association. Nature 307: 161–163. - PubMed
    1. Rugg MD (1985) The effects of semantic priming and word repetition on event-related potentials. Psychophysiology 22: 642–647. - PubMed
    1. Bentin S, McCarthy G, Wood CC (1985) Event-related potentials, lexical decision and semantic priming. Electroencephalography and Clinical Neurophysiology 60: 343–355. - PubMed
    1. Collins AM, Loftus EF (1975) Spreading Activation Theory of Semantic Processing. Psychological Review 82: 407–428.

Publication types

LinkOut - more resources