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Two Choice Dilemma Questionnaire items were used to investigate the influence of persuasive arguments and social decision schemes on group decisions. Furthermore, the predictions of the persuasive arguments theory on the polarization of individual preferences were tested. Ss were given lists of persuasive arguments and a 2nd individual decision was requested before the group discussion. The lists of persuasive arguments were compiled through a stepwise process of rating data gathered from the content analysis of former group discussions. In Condition 1, the Ss received the lists of arguments before the 1st individual decision; in Condition 2, between the 1st and 2nd individual measure; and in Condition 3 (control), they received no list at all. In all 3 conditions the reduced paired comparison median model showed the best fit and the highest hit rate in predicting the group decisions. The resulting choice shift could not be explained by the influence of arguments, whereas the best-fitting aggregation rule was able to clarify the choice shift.Choice shift has come to mean the difference between the arithmetic mean of the individual first preferences before discussion (prediscussion preferences) and the group decision. The concept of group polarization traditionally denotes the differences between the prediscussion preferences and the individual first preferences after group discussion (postdiscussion preferences; (Hinsz & Davis, 1984;Kaplan, 1987;Kaplan & Miller, 1983). Furthermore, we define individual polarization as the change in individual preferences between two measures without group discussion or decision.Choice shift and group polarization need not, however, be of equal magnitude. Therefore, it is important to distinguish between the group level (choice shift) and the individual level (individual polarization and group polarization). Contrary to many contemporary treatments, these two levels should not be considered equivalent.When one reviews the research on choice shift and group polarization over the last few years, the following tendency surfaces: Many of the abundant explanations for these phenomena (see the critical reviews from Cartwright 1971Cartwright , 1973Dion, Baron, & Miller, 1970; and Pruitt 1971a, 1971b) had to be discounted as inapplicable. According to the reviews of Kaplan and Miller (1983) and Kaplan (1987), only a few of the empiri-Research was carried out at the University of Freiburg, Federal Republic of Germany, with funds from the Deutsche Forschungsgemeinschaft.We thank Judith Whittaker-Stemmler for her help with the transcription from German to English.

Multiple theories attribute to the primate prefrontal cortex a critical role in conscious perception. However, opposing views caution that prefrontal activity could reflect other cognitive variables during paradigms investigating consciousness, such as decision-making, monitoring and motor reports. To resolve this ongoing debate, we recorded from prefrontal ensembles of macaque monkeys during a no-report paradigm of binocular rivalry that instigates internally driven transitions in conscious perception. We could decode the contents of consciousness from prefrontal ensemble activity during binocular rivalry with an accuracy similar to when these stimuli were presented without competition. Oculomotor signals, used to infer conscious content, were not the only source of these representations since visual input could be significantly decoded when eye movements were suppressed. Our results suggest that the collective dynamics of prefrontal cortex populations reflect internally generated changes in the content of consciousness during multistable perception. One sentence summaryNeural correlates of conscious perception can be detected and perceptual contents can be reliably decoded from the spiking activity of prefrontal populations.

A major debate about the neural correlates of conscious perception concerns its cortical organization, namely, whether it includes the prefrontal cortex (PFC), which mediates executive functions, or it is constrained within posterior cortices. It has been suggested that PFC activity during paradigms investigating conscious perception is conflated with post-perceptual processes associated with reporting the contents of consciousness or feedforward signals originating from exogenous stimulus manipulations and relayed via posterior cortical areas. We addressed this debate by simultaneously probing neuronal populations in the rhesus macaque (Macaca mulatta) PFC during a no-report paradigm, capable of instigating internally generated transitions in conscious perception, without changes in visual stimulation. We find that feature-selective prefrontal neurons are modulated concomitantly with subjective perception and perceptual suppression of their preferred stimulus during both externally induced and internally generated changes in conscious perception. Importantly, this enables reliable single-trial, population decoding of conscious contents. Control experiments confirm significant decoding of stimulus contents, even when oculomotor responses, used for inferring perception, are suppressed. These findings suggest that internally generated changes in the contents of conscious visual perception are reliably reflected within the activity of prefrontal populations in the absence of volitional reports or changes in sensory input.

SignificanceThe spatial structure of correlated activity of neurons in lower-order visual areas has been shown to linearly decrease as a measure of distance. The shape of correlated variability is a defining feature of cortical microcircuits, as it constrains the computational power and diversity of a region. We show here a nonmonotonic spatial structure of functional connectivity in the prefrontal cortex (PFC) where distal interactions are just as strong as proximal interactions during visual engagement of functionally similar PFC neurons. Such a nonmonotonic structure of functional connectivity could have far-reaching consequences in rethinking the nature and role of prefrontal microcircuits in various cognitive states.

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In perceptual multistability, the content of consciousness alternates spontaneously between different interpretations of unchanged sensory input. The source of these internally driven transitions in conscious perception is unknown. Here we show that transient, low frequency (1-9 Hz) perisynaptic bursts in the macaque lateral prefrontal cortex precede spontaneous perceptual transitions in a no-report binocular motion rivalry task. These lowfrequency transients suppress 20-40 Hz oscillatory bursts that selectively synchronise the discharge activity of neuronal ensembles signalling conscious content. Similar ongoing state changes, with dynamics resembling the temporal structure of spontaneous perceptual alternations during rivalry, dominate the prefrontal cortex during resting-state, thus pointing to their default, endogenous nature. Our results suggest that prefrontal state fluctuations control access to consciousness through a reorganisation in the activity of feature-specific neuronal ensembles. One sentence summaryPrefrontal state transitions precede spontaneous transitions in the content of consciousness. | Pageusing a no-report BR paradigm. This allowed us to detect intrinsically driven transitions in conscious perception of opposing directions-of-motion. We combined this task with multielectrode recordings of local field potentials (LFPs) and simultaneously sampled direction-of-motion selective, competing ensembles. By using the optokinetic nystagmus (OKN) reflex as an objective criterion of perceptual state transitions, we removed any effects of voluntary motor reports on neural activity, identifying signals directly related to spontaneous transitions in the content of consciousness. ResultsWe used a no-report paradigm of binocular motion rivalry coupled with multielectrode extracellular recordings of LFPs and direction-of-motion selective neuronal ensembles in the inferior convexity of the macaque PFC ( Fig. 1A). Two types of trials were employed: a) physical alternation (PA) of monocular alternating, opposing directions of motion and b) binocular rivalry (BR) where the initial direction of motion was not removed but was followed by a flashed, opposing direction of motion in the contralateral eye ( Fig. 1B, upper panel).Initially, this manipulation results in an externally induced period of perceptual suppression of variable duration for the first stimulus (binocular flash suppression -BFS) which is followed by spontaneous perceptual transitions since the two competing representations start to rival for access to consciousness. In order to exclude the effect of voluntary perceptual reports on neural activity the macaques were not trained to report their percept. Instead, the polarity of their motion-induced optokinetic nystagmus reflex (OKN) elicited during passive observation of the stimuli (in both conditions, i.e. BR and PA), and previously shown to provide an accurate perceptual state read-out in both humans and macaques, was used to infer perceptual dominance periods (Fig. 1B, lower panel). These domin...

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