Evidence for a 40-Hz oscillatory short-term visual memory revealed by human reaction-time measurements.

Abstract

Four experiments show that presentation of a synchronous premask frame within a 40-Hz, flickering premask matrix primes subsequent detection of a Kanizsa-type square by generation of a 40-Hz prime. Reaction time (RT) priming effects indicated a 150-200-ms prime duration following premask display. Kite were also found to be sensitive to the phase relationship between offset of the premask display relative to the onset time of the target: Priming effects were maximal when the target was presented out of phase with premask presentation (i.e., at interstimulus intervals displaced by 180° relative to the 40-Hz rhythm of premask-frame presentation). Taken together, these results demonstrate the existence of a very short-term visual memory that oscillates at 40 Hz. The findings are discussed in the context of complementary psychological and neurophysiological findings related to visual-object coding and the role of gamma-band activity in the brain.In order to represent the organization of separable feature elements as a single perceptual entity, the elements must be independently coded and then recombined or "bound" into a composite object representation. Neurophysiological studies have demonstrated that separate features of a stimulus object are coded by functionally specialized neurons, optimally tuned to particular stimulus attributes such as length, spatial frequency, spectral density, and orientation (e.g., Hubel & Wiesel, 1959;Livingstone & Hubel, 1988). In addition, recent single-cell recording studies have demonstrated that, although features belonging to the same object are coded by separate neurons, these neurons adjust their firing patterns to fire in synchrony. These findings have led to the hypothesis that synchronization of patterns of activity among featurecoding neurons is the most likely neurophysiological correlate of psychophysical "feature binding" (e.g., Gray, Konig, Engel, & Singer, 1989).The electrophysiological recordings of synchronized neuronal activity have typically been obtained from a series of

The effects of subthreshold synchrony on the perception of simultaneity

“…A second set of studies has shown perception to be influenced directly by the timing of subthreshold stimuli. More specifically, these findings have shown that the coding of spatial grouping is expedited following the prior presentation of rapidly repeating premask elements in the same phase of a multi-element and multiphase presentation matrix (Elliott & Mu¨ller, 1998, 2000, 2001. In these studies, the premask elements, which were divided across a number of presentation phases, were presented repeatedly and at high frequency such that the precise temporal relations between the elements could not be determined by observers (Elliott & Mu¨ller, 1998, Experiment 2).…”

Prefrontal cortex and the generation of oscillatory visual persistence

“…One line of evidence relates to the subthreshold, oscillatory-priming effects reported by Elliott and colleagues (Elliott & Müller, 1998, 2000Kompass & Elliott, 2001). Prime responses exhibit a number of particular temporal characteristics: Primes persist for duration shorter than that of iconic memory but consistent with the persistence of a visible stimulus (i.e.…”

“…Prime responses exhibit a number of particular temporal characteristics: Primes persist for duration shorter than that of iconic memory but consistent with the persistence of a visible stimulus (i.e. <= 300 ms, see Coltheart, 1980), and are periodic, characterized by the frequency of priming-display presentations (the prime reaction time (RT) x premask-target ISI functions were periodic with a frequency of around 40 Hz, see Elliott & Müller, 2000). That prime persistence comes to be characterized by the frequency of prime-display presentation (the priming stimulus comprises one of four repeatedly presented but asynchronized image frames each presented at 10 Hz) has been taken as an indication that the prime is generated by mechanisms capable of coding global stimulus properties in interaction with relatively early visual-coding mechanisms.…”

“…The pattern of coactivation between neural assemblies under Fp1 and O2/P3 thus offers itself as a strong candidate for generation of the anticipatory response reported by Kompass and Elliott. Two points emerge from the analyses presented here. The first is that prefrontalposterior synchronization appears to be involved in the formation of stimulus-related persistence, which has been shown to possess a duration sufficiently short to suggest coactive neural assemblies may remain functional for as little as 200 -300 ms poststimulus offset (Elliott & Müller, 2000). The second is that at least one characteristic of the prime response, the temporal precession of prime activity relative to target display presentation, may emerge as a function of cascading fluctuations in coherence between various frequency responses to prime stimulus presentation.…”

Bandpass characteristics of high-frequency sensitivity and visual experience in blindsight

“…Engel, Kreiter, König, & Singer, 1991;Kreiter & Singer, 1992). In a second line of evidence Elliott and colleagues (Elliott & Müller, 1998, 2000 have shown that a masked grouping embedded in a flickering display will prime detection of a subsequent grouping only if the masked grouping is embedded within 40 Hz flicker. Further examination of the temporal specificity of these effects was reported by Elliott and Müller (2004) who showed several specific bandpass characteristics located at 32 Hz, between 37 and 40 Hz and between 46 and 47 Hz.…”