Psychophysical and neurometric detection performance under stimulus uncertainty.
Signal detection theoretical analyses of spike counts have revealed that some cortical neurons can exceed psychophysical sensitivity in cases where a sensory signal is specified exactly. It is not known whether this finding holds in the more natural situation where signal occurrence is temporally uncertain. We investigated the ability of rat barrel cortex neurons to detect faint and transient whisker deflections occurring at unspecified times. The progression from fully specified stimuli to temporal uncertainty degraded neuronal sensitivity such that it seems highly unlikely that single neurons can provide the basis for decoding uncertain perceptual events. However, modeling the sensitivity of neuronal pools on basis of spike timing precision across several neurons in an optimal encoding window of 25 ms showed that the subject's perceptual sensitivity could be based on the occurrence of coincident spikes from four to five neurons.
Stüttgen
Maik C
MC
Hertie-Institute for Clinical Brain Research, Department of Cognitive Neurology, University of Tübingen, 72076 Tübingen, Germany.
Schwarz
Cornelius
C
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal; D002540:Cerebral Cortex / Q000166:cytology*; D008297:Male; D008959:Models, Neurological; D009010:Monte Carlo Method; D009474:Neurons / Q000145:classification / Q000502:physiology*; D010812:Physical Stimulation; D011601:Psychophysics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D017603:Signal Detection, Psychological / Q000502:physiology*; D013997:Time Factors; D014738:Vibrissae / Q000294:innervation; D014851:Wakefulness