Synchronous firing in the second somatosensory cortex (SII) covaries with the attentional state of alert monkey

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“Synchronous firing in the second somatosensory cortex (SII) covaries with the attentional state of alert monkey” by P. N. Steinmetz, A. Roy, P. Fitzgerald, S. S. Hsiao, E. Niebur, and K. O. Johnson. Soc. Neurosci. Abstr., vol. 28, Nov. 1998.

Abstract

The degree of correlated activity of pairs of neurons recorded simultaneously in area SII of an alert behaving monkey was examined. During the recordings, the animal's focus of attention switched between performing a tactile discrimination task, where the animal was required to match the orientations of two sequentially presented bars pressed onto the monkey's fingerpad, and performing a visual task, where the animal was required to detect the dimming of a figure presented on a screen while receiving identical tactile stimulation (see Fitzgerald, Lane and Hsiao, this volume for details). The neurons of each pair were recorded from different electrodes separated by at least 400 mms. Correlations were determined after applying a shift predictor to correct for variations in evoked firing rate. Of the total 101 neurons examined, 50 (50%) were members of at least one pair that showed significant effects of attention on correlation. A total of 150 pairs was examined. 18 pairs (12%) showed significant (p<0.01) synchronous firing, with the half-width of the cross-correlation peak approximately 25 ms, and with the degree of correlation covarying with the attentional state of the monkey (8% positive, 4% negative). An 8 additional pairs (5%) showed significant correlation (p<0.01) with a wider cross-correlation peak (half-width  50 ms). 6 pairs (4%) showed significant (p<0.01) inhibition of one neuron by the other which was affected by attention, typically within 50 ms. Correlation between the remaining 118 pairs (79%) was unaffected by attention. These results indicate that attention changes not only the mean rate of firing of neurons (Hsiao et al., J. Neurophys. 7:444, 1993) but also, for nearly one half of the neurons examined, the degree of synchronization with other neurons as well.

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BibTeX entry:

@article{Steinmetz_etal98a,
   author = {P. N. Steinmetz and A. Roy and P. Fitzgerald and S. S. Hsiao
	and E. Niebur and K. O. Johnson},
   title = {Synchronous firing in the second somatosensory cortex (SII)
	covaries with the attentional state of alert monkey},
   journal = {Soc. Neurosci. Abstr.},
   volume = {28},
   pages = {1513},
   month = nov,
   year = {1998}
}