Showing papers by "Rodrigo Quian Quiroga published in 2009"
TL;DR: To further understand how the brain processes information, it is important to shift from a single-neuron, multiple-trial framework to multiple-NEuron, single-trial methodologies.
Abstract: To a large extent, progress in neuroscience has been driven by the study of single-cell responses averaged over several repetitions of stimuli or behaviours. However,the brain typically makes decisions based on single events by evaluating the activity of large neuronal populations. Therefore, to further understand how the brain processes information, it is important to shift from a single-neuron, multiple-trial framework to multiple-neuron, single-trial methodologies. Two related approaches--decoding and information theory--can be used to extract single-trial information from the activity of neuronal populations. Such population analysis can give us more information about how neurons encode stimulus features than traditional single-cell studies.
675 citations
TL;DR: It is demonstrated that single neurons can encode percepts in an explicit, selective, and invariant manner, even if evoked by different sensory modalities, as well as the degree of multimodal invariance increases along the hierarchical structure within the MTL.
179 citations
TL;DR: The method uses a hybrid and computationally simple approach, where the features of the background noise arise naturally from its biophysical process of generation, and generates data that resemble the characteristics of real recordings, as quantified by the amplitude and frequency distributions.
100 citations
TL;DR: The findings indicate that personally relevant photographs are indeed more likely to elicit selective responses in MTL neurons than photographs of individuals with whom the patients have had no personal contact, and suggest that relevant stimuli are encoded by a larger proportion of neurons than less relevant stimuli.
Abstract: People with whom one is personally acquainted tend to elicit richer and more vivid memories than people with whom one does not have a personal connection. Recent findings from neurons in the human medial temporal lobe (MTL) have shown that individual cells respond selectively and invariantly to representations of famous people [Quian Quiroga R, Reddy L, Kreiman G, Koch C, Fried I (2005) Nature 435(7045):1102–1107]. Observing these cells, we wondered whether photographs of personally relevant individuals, such as family members, might be more likely to generate such responses. To address this issue, we recorded the activity of 2,330 neurons in the human MTL while patients viewed photographs of varying personal relevance: previously unknown faces and landscapes, familiar but not necessarily personally relevant faces and landscapes, and finally, photographs of the patients themselves, their families, and the experimenters. Our findings indicate that personally relevant photographs are indeed more likely to elicit selective responses in MTL neurons than photographs of individuals with whom the patients have had no personal contact. These findings further suggest that relevant stimuli are encoded by a larger proportion of neurons than less relevant stimuli, given that familiar or personally relevant items are linked to a larger variety of experiences and memories of these experiences.
98 citations
01 Jan 2009
TL;DR: This review, discusses the main experiments with recording of single neurons and related evidence about the neural events underling visual perceptual awareness with single cell recordings in monkeys and voxel activities with human fMRI experiments.
Abstract: The study of the neural correlates of awareness is nowadays an active research field in Neuroscience. This has been basically boosted by the study of neural correlates of conscious perception with single cell recordings in monkeys and voxel activities with human fMRI experiments. In this review, we discuss the main experiments with recording of single neurons and related evidence about the neural events underling visual perceptual awareness. Alberto Capurro and Rodrigo Quian Quiroga University of Leicester Department of Engineering NeuroEngineering Lab Several researchers are now experimentally addressing the study of the neural correlates of the different aspects of consciousness. This issue was considered to be an exclusive matter of philosophy until a short time ago (Crick, 1994; Crick and Koch, 1995; Koch, 2004). Consciousness or awareness can, in principle, be defined as the occurrence of perceptions, thoughts and feelings (Sutherland, 1996). A precise definition, however, remains elusive, because covering every aspect of the conscious experience is difficult. For instance, speaking about the perception of something that we see and recognize is not the same as speaking about our self consciousness, or about the different levels of awareness that we experience during the sleep-wake cycle. To begin with, we must distinguish between the factors that enable consciousness to occur (such as the ascending activation system of the brainstem and basal forebrain, or the glutamatergic neurotransmission) from the so called content of consciousness, that is, the formation of specific percepts. In this review we will address this last issue through evidence of neural correlates underling visual perceptual awareness. i ac331@leicester.ac.uk ii rqqg1@leicester.ac.uk iii LE1 7RH Leicester, United Kingdom Tel / Fax: +44 (0)116 252 2314 / 2619 www.le.ac.uk/neuroengineering
3 citations