Open Access Repository

Mismatch negativity to stimulus omission?


Downloads per month over past year

Gourley, Maurice V 1993 , 'Mismatch negativity to stimulus omission?', Unspecified thesis, University of Tasmania.

[img] PDF (Whole thesis)
whole_GourleyMa...pdf | Request a copy
Full text restricted
Available under University of Tasmania Standard License.


The present experiment explored the effects of stimulus omission
on mismatch negativity elicitation under varying conditions of
attention. Fifty subjects were divided into five groups based on
attentional focus during stimulus presentation. The three
experimental groups (all of whom received 10% omitted stimuli)
included a Reading (ignore all stimuli) Group, a Counting (attend to
omitted stimulus) Group, and a Passive Attend (attend to stimuli
alone) Group. The two Control Groups (all of whom received 100%
standard stimuli) comprised a Reading (ignore all stimuli) Group and
a Passive Attend (attend to all stimuli alone) Group.
Stimuli were presented to the subjects in a single channel
binaural auditory oddball paradigm. Subjects responses to the rare
tones and also to the tone prior to the rare (pre) and following the rare
(post) were monitored using EEG electrodes at three vertex sites (Fz,
Cz, and Pz). Results indicated, (in contrast to orienting responses to
omission), that there was little evidence of any mismatch negativity to
omitted stimuli in any of the attentional conditions employed within
the experiment.
The results did not provide any support for Naatanen's (1990)
suggestion that MMN may be an integral component of, or at least
associated with, the OR since both appear to be preattentive neuronal
mismatch mechanisms. The results did however suggest that
refractory effects occurred in Post responses to the standard stimulus
immediately following an omission. In addition, there was some
evidence of dishabituation in the Post responses of the Reading
(Ignore) Group. Only the Counting Group exhibited a significant P300
in response to the omitted stimuli predominantly at the Cz and Pz
sites. The relationship between attention and mismatch negativity
and its unique response to omission are considered in light of the
current findings.

Item Type: Thesis - Unspecified
Authors/Creators:Gourley, Maurice V
Keywords: Attention, Human information processing
Copyright Holders: The Author
Additional Information:

Thesis (M.Psych.)--University of Tasmania, 1994. Includes bibliographical references (leaves 80-88)

Item Statistics: View statistics for this item

Actions (login required)

Item Control Page Item Control Page