D. M. Mackay, P. H. Schiller, N. K. Logothetis, E. R. Charles, C. E. Byrne, ...
Although long considered to be of marginal importance toglobal climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has...
Dynamic Amplitude Coding in the Auditory Cortex of Awake Rhesus Macaques (2008)
Li Liang, Thomas Lu, Xiaoqin Wang, J Neurophysiol, D. L. Rathbun, R. Moucha, ...
You might find this additional information useful... This article cites 44 articles, 13 of which you can access free at:
Separation of Spatial and Reward Responses on the Multiple T Task (2008)
Neil Schmitzer-torbert, A. David Redish, B. Lau, P. W. Glimcher, A. S. Tolias, A. S. Ecker, ...
You might find this additional information useful... This article cites 56 articles, 23 of which you can access free at:
Smart Magnetic Resonance Imaging Agents that Sense Extracellular Calcium Fluctuations (2008)
Angelovski, G., Fouskova, P., Mamedov, I., Canals, S., Toth, E., Logothetis, N.K.
Gd3+ chelates linked to a modified EGTA moiety were prepared in order to respond to extracellular Ca2+ fluctuations in the brain Gd3+ chelates linked to a modified EGTA moiety were prepared in order...
fMRI and its interpretations: an illustration on directional selectivity in area V5/MT (2008)
Bartels, A., Logothetis, N.K., Moutoussis, K.
fMRI is a tool to study brain function noninvasively that can reliably identify sites of neural involvement for a given task. However, to what extent can fMRI signals be related to measures obtained...
Bartels, A., Zeki, S., Logothetis, N.K.
Visual changes in feature movies, like in real-live, can be partitioned into global flow due to self/camera motion, local/ differential flow due to object motion, and residuals, for example, due to...
Belitski, A., Gretton, A., Magri, C., Murayama, Y., Montemurro, M.A., Logothetis, N.K., ...
Local field potentials (LFPs) reflect subthreshold integrative processes that complement spike train measures. However, little is yet known about the differences between how LFPs and spikes encode...
Berens, P., Keliris, G.A., Ecker, A.S., Logothetis, N.K., Tolias, A.S.
The local field potential (LFP), comprised of low-frequency extra-cellular voltage fluctuations, has been used extensively to study the mechanisms of brain function. In particular, oscillations in...
Berens, P., Keliris, G.A., Ecker, A.S., Logothetis, N.K., Tolias, A.S.
Extra-cellular voltage fluctuations (local field potentials; LFPs) reflecting neural mass action are ubiquitous across species and brain regions. Numerous studies have characterized the properties of...
Magnetic Resonance Imaging of Cortical Connectivity in vivo (2008)
Canals, S., Beyerlein, M., Keller, A.L., Murayama, Y., Logothetis, N.K.
Electric stimulation fMRI of the perforant pathway to the rat hippocampus (2008)
Canals, S., Beyerlein, M., Murayama, Y., Logothetis, N.K.
The hippocampal formation is a brain system that is implicated in learning and memory. The major input to the hippocampus arrives from the entorhinal cortex (EC) to the dentate gyrus (DG) through the...
Morphing rhesus monkey vocalizations (2008)
Chakladar, S., Logothetis, N.K., Petkov, C.I.
The capability to systematically morph between different types of animal vocalizations will give us insights into how the features of vocal sounds are perceived by listening individuals. Following...
Synthesis and Characterization of a Smart Contrast Agent Sensitive to Calcium (2008)
Dhingra, K., Maier, M.E., Beyerlein, M., Angelovski, G., Logothetis, N.K.
A novel first-generation Ca2+ sensitive contrast agent, Gd-DOPTRA has been synthesized and characterized. The agent shows 100% relaxivity enhancement upon addition of Ca2+. The agent is selective and...
Dhingra, K., Fousková, P., Angelovski, G., Maier, M.E., Logothetis, N.K., Tóth, E.
Two new bismacrocyclic Gd3+ chelates containing a specific Ca2+ binding site were synthesized as potential MRI contrast agents for the detection of Ca2+ concentration changes at the millimolar level...
Neurophysiology of the BOLD fMRI Signal in Awake Monkeys (2008)
Goense, J.B.M., Logothetis, N.K.
Background Simultaneous intracortical recordings of neural activity and blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in primary visual cortex of anesthetized...
fMRI of the temporal lobe of the awake monkey at 7 T (2008)
Goense, J.B.M., Merkle, H., Tolias, A.S., Logothetis, N.K.
Increasingly 7 T scanners are used for fMRI of humans and non-human primates, promising improvements in signal-to-noise, spatial resolution and specificity. A disadvantage of fMRI at 7 T, but already...
Category-specific responses to faces and objects in primate auditory cortex (2008)
Hoffman, K.L., Ghanzafar, A.A., Gauthier, I., Logothetis, N.K.
Auditory and visual signals often occur together, and the two sensory channels are known to infl uence each other to facilitate perception. The neural basis of this integration is not well...
Visual modulation of neurons in auditory cortex (2008)
Kayser, C., Petkov, C.I., Logothetis, N.K.
Our brain integrates the information provided by the different sensory modalities into a coherent percept, and recent studies suggest that this process is not restricted to higher association areas....
Gretton, A., Macke, J., Logothetis, N.K.
Pattern recognition methods have shown that functional magnetic resonance imaging (fMRI) data can reveal significant information about brain activity. For example, in the debate of how object...
What we can do and what we cannot do with fMRI (2008)
Functional magnetic resonance imaging (fMRI) is currently the mainstay of neuroimaging in cognitive neuroscience. Advances in scanner technology, image acquisition protocols, experimental design, and...
Mazzoni, A., Panzeri, S., Logothetis, N.K., Brunel, N.
Recordings of local field potentials (LFPs) reveal that the sensory cortex displays rhythmic activity and fluctuations over a wide range of frequencies and amplitudes. Yet, the role of this kind of...
Phase-of-Firing Coding of Natural Visual Stimuli in Primary Visual Cortex (2008)
Montemurro, M.A., Rasch, M.J., Murayama, Y., Logothetis, N.K., Panzeri, S.
We investigated the hypothesis that neurons encode rich naturalistic stimuli in terms of their spike times relative to the phase of ongoing network fluctuations rather than only in terms of their...
Object features used by humans and monkeys to identify rotated shapes (2008)
Nielsen, K.J., Logothetis, N.K., Rainer, G.
Humans and rhesus monkeys can identify shapes that have been rotated in the picture plane. Recognition of rotated shapes can be as efficient as recognition of upright shapes. Here we investigate...
A voice region in the monkey brain (2008)
Petkov, C.I., Kayser, C., Steudel, T., Whittingstall, K., Augath, M., Logothetis, N.K.
For vocal animals, recognizing species-specific vocalizations is important for survival and social interactions. In humans, a voice region has been identified that is sensitive to human voices and...
Inferring Spike Trains From Local Field Potentials (2008)
Rasch, M.J., Gretton, A., Murayama, Y., Maass, W., Logothetis, N.K.
We investigated whether it is possible to infer spike trains solely on the basis of the underlying local field potentials (LFPs). Using support vector machines and linear regression models, we found...
Rauch, A., Rainer, G., Augath, M., Oeltermann, A., Logothetis, N.K.
Pharmacological magnetic resonance imaging (phMRI) is a current direction in biomedical imaging, whose goal is the non-invasive monitoring of pharmacological manipulations on brain processes. We have...
Rauch, A., Rainer, G., Logothetis, N.K.
The relationship of the blood oxygen-level-dependent (BOLD) signal to its underlying neuronal activity is still poorly understood. Combined physiology and functional MRI experiments suggested that...
fMRI measurements of color in macaque and human (2008)
Wade, A., Augath, M., Logothetis, N.K., Wandell, B.
We have used fMRI to measure responses to chromatic and achromatic contrast in retinotopically defined regions of macaque and human visual cortex. We make four observations. Firstly, the relative...
Wang, Z., Maier, A., Logothetis, N.K., Liang, H.
We propose an empirical mode decomposition (EMD-) based method to extract features from the multichannel recordings of local field potential (LFP), collected from the middle temporal (MT) visual...
Single-Trial Decoding of Bistable Perception Based on Sparse Nonnegative Tensor Decomposition (2008)
Wang, Z., Maier, A., Logothetis, N.K., Liang, H.
The study of the neuronal correlates of the spontaneous alternation in perception elicited by bistable visual stimuli is promising for understanding the mechanism of neural information processing and...
Wang, Z., Logothetis, N.K., Liang, H.
Bistable perception emerges when a stimulus under continuous view is perceived as the alternation of two mutually exclusive states. Such a stimulus provides a unique opportunity for understanding the...
The microvascular system of the striate and extrastriate visual cortex of the macaque (2008)
Weber, B., Keller, A.L., Reichold, J., Logothetis, N.K.
In functional neuroimaging, neurovascular coupling is used to generate maps of hemodynamic changes that are assumed to be surrogates of regional neural activation. The aim of this study was to...
The Influence of Moderate Hypercapnia on Neural Activity in the Anesthetized Nonhuman Primate (2008)
Uludag, K., Oeltermann, A., Ugurbil, K., Logothetis, N.K.
Hypercapnia is often used as vasodilatory challenge in clinical applications and basic research. In functional magnetic resonance imaging (fMRI), elevated CO2 is applied to derive stimulus-induced...
Direct measurement of oxygen extraction with fMRI using 6% CO2 inhalation (2008)
The blood oxygenation level-dependent (BOLD) signal is an indirect hemodynamic signal which is sensitive to cerebral blood flow (CBF), cerebral blood volume (CBV) and cerebral metabolic rate of...
Mass spectrometry-based neurochemical analysis: perspectives for primate research (2008)
Zhang, X., Rauch, A., Xiao, H., Rainer, G., Logothetis, N.K.
The analysis of neurochemicals from the brain represents a challenge for current analytical techniques due to a variety of factors, such as compositional complexity, limited amounts of sample and...
The Influence of Moderate Hypercapnia on Neural Activity in the Anesthetized Nonhuman Primate (2008)
Zappe, A.C., Uludag, K., Oeltermann, A., Ugurbil, K., Logothetis, N.K.
Hypercapnia is often used as vasodilatory challenge in clinical applications and basic research. In functional magnetic resonance imaging (fMRI), elevated CO2 is applied to derive stimulus-induced...
The Role of Attention in Binocular Rivalry as Revealed through Optokinetic Nystagmus (2007)
D. A. Leopold, J. C. Fitzgibbons, N. K. Logothetis
This publication can be retrieved by anonymous ftp to publications.ai.mit.edu. When stimuli presented to the two eyes di er considerably, stable binocular fusion fails, and the subjective percept...
C.B.C.L. Paper No. 125 On the Physiology of Bistable Percepts (2007)
N. K. Logothetis, D. A. Leopold
This publication can be retrieved by anonymous ftp to publications.ai.mit.edu. Binocular rivalry refers to the alternating perceptions experienced when two dissimilar patterns are stereoscopically...
Individuation and holistic processing of faces in Rhesus monkeys (2007)
Dahl, C.D., Logothetis, N.K., Hoffman, K.L.
Despite considerable evidence that neural activity in monkeys reflects various aspects of face perception, relatively little is known about monkeys face processing abilities. Two characteristics of...
High-resolution fMRI of macaque V1 (2007)
Goense, J.B.M., Logothetis, N.K.
To understand the physiological mechanisms underlying the blood-oxygenation-level-dependent (BOLD) signal, the acquisition of data must be optimized to achieve the maximum possible spatial resolution...
The ins and outs of fMRI signals (2007)
Despite the widespread use of functional magnetic resonance imaging, we still do not fully understand what it measures. A new study reports that oxygen-concentration changes and local field...
Facial-Expression and Gaze-Selective Responses in the Monkey Amygdala (2007)
Hoffman, K.L., Gothard, K.M., Schmid, M.C., Logothetis, N.K.
The social behavior of both human and nonhuman primates relies on specializations for the recognition of individuals, their facial expressions, and their direction of gaze [1], [2], [3], [4] and [5]....
Logothetis, N.K., Kayser, C., Oeltermann, A.
To combine insights obtained from electric field potentials (LFP) and neuronal spiking activity (MUA) we need a better understanding of the relative spatial summation of these indices of neuronal...
Zhang, X., Rauch, A., Lee, H., Xiao, H., Rainer, G., Logothetis, N.K.
A diverse array of neurotransmitters and neuromodulators control and affect brain function. A profound understanding of the signaling pathways and the neural circuits underlying behavior is therefore...
Juchem, C., Logothetis, N.K., Pfeuffer, J.
A pronounced characteristic of the microcircuits of the primary visual cortex (striate cortex or area V1) in primates is the strong recurrent excitation and the tight balance between excitation and...
Smirnakis, S.M., Schmid, M.C., Weber, B., Tolias, A.S., Augath, M., Logothetis, N.K.
Intravascular contrast agents are used in functional magnetic resonance imaging to obtain cerebral blood volume (CBV) maps of cortical activity. Cerebral blood volume imaging with MION...
A method for generating a purely first-order dichoptic motion stimulus (2007)
Hayashi, R., Nishida, S., Tolias, A., Logothetis, N.K.
In the present technical article, we describe a method for generating a new dichoptic motion stimulus, the monocular components of which are dynamic random noise without constant figural cues for...
Synthesis and Characterization of Lanthanide Complexes of DO3A-Alkylphosphonates (2007)
Mamedov, I., Mishra, A., Angelovski, G., Mayer, H.A., Parker, D., ...
Silver, M.A., Logothetis, N.K.
The nature of competition underlying perceptual alternations in binocular rivalry remains controversial. Interocular swapping of rivalrous stimuli can result in either slow irregular perceptual...
Simultaneous recording of neuronal signals and functional NMR imaging (2007)
Oeltermann, A., Augath, M.A., Logothetis, N.K.
We recently directly examined the relationship between blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals and neural activity by simultaneously acquiring...
Spatio-temporal point-spread function of fMRI signal in human gray matter at 7 Tesla (2007)
Shmuel, A., Yacoub, E., Chaimow, D., Logothetis, N.K., Ugurbil, K.
Reichold, J., Burger, C., Weber, B., Buck, A., Pfeuffer, J., ...
Noninvasive absolute quantification of cerebral blood flow (CBF) with high spatial resolution is still a challenging task. Arterial spin labeling (ASL) is a promising magnetic resonance imaging (MRI)...
Functional imaging reveals visual modulation of specific fields in auditory cortex (2007)
Kayser, C., Petkov, C.I., Augath, M., Logothetis, N.K.
Merging information from different senses is essential for successfully interacting with real world situations. Indeed, sensory integration can reduce perceptual ambiguity, speed reactions or change...
Spatial specificity of CBV and BOLD fMRI in monkey striate cortex at 4.7T and 7T (2007)
Logothetis, N.K., Goense, J.B.M.
High resolution fMRI allows us to determine more accurately the origins of the fMRI signal. This has shown that even at high field, the GE-BOLD signal has still a large vascular contribution [1]....
Tuning to sound frequency in auditory field potentials (2007)
Kayser, C., Petkov, C.I., Logothetis, N.K.
Neurons in auditory cortex are selective for the frequency content of acoustical stimuli. Classically, this response selectivity is studied at the single neuron level. However, current research often...
A novel functional magnetic resonance imaging compatible search-coil eye-tracking system (2007)
Oeltermann, A., Logothetis, N.K.
Measuring eye movements (EMs) using the search-coil eye-tracking technique is superior to video-based infrared methods [Collewijn H, van der Mark F, Jansen TC. Precise recording of human eye...
Do early sensory cortices integrate cross-modal information? (2007)
Our different senses provide complementary evidence about the environment and their interaction often aids behavioral performance or alters the quality of the sensory percept. A traditional view...
Recording Chronically from the same Neurons in Awake, Behaving Primates (2007)
Tolias, A.S., Ecker, A.S., Siapas, A.G., Hoenselaar, A., Keliris, G.A., Logothetis, N.K.
Understanding the mechanisms of learning requires characterizing how the response properties of individual neurons and interactions across populations of neurons change over time. In order to study...
Improvement of visual contrast detection by a simultaneous sound (2007)
Lippert, M., Logothetis, N.K., Kayser, C.
Combining input from multiple senses is essential for successfully mastering many real world situations. While several studies demonstrate that the presentation of a simultaneous sound can enhance...
Vocal-Tract Resonances as Indexical Cues in Rhesus Monkeys (2007)
Ghazanfar, A.A., Turesson, H.K., Maier, J.X., Dinther, R., Patterson, R.D., Logothetis, N.K.
Vocal-tract resonances (or formants) are acoustic signatures in the voice and are related to the shape and length of the vocal tract. Formants play an important role in human communication, helping...
Invited Review Correcting for the Sampling Bias Problem in Spike Train Information Measures (2007)
Stefano Panzeri, Riccardo Senatore, Marcelo A. Montemurro, Rasmus S, M. J. Rasch, A. Gretton, ...
You might find this additional information useful... This article cites 26 articles, 10 of which you can access free at:
Zappe, A., Merkle, H., Pfeuffer, J., Logothetis, N.K.
Perfusion-based imaging in the monkey primary visual cortex was performed at 7 T applying continuous arterial spin labeling (CASL). Increased perfusion sensitivity and SNR at high magnetic field (due...
Direct and Indirect Activation of Cortical Neurons by Electrical Microstimulation (2006)
Tehovnik, E.J., Tolias, A.S., Sultan, F., Slocum, W.M., Logothetis, N.K.
Electrical microstimulation has been used to elucidate cortical function. This review discusses neuronal excitability and effective current spread estimated by using three different methods: 1)...
Shmuel, A., Augath, M., Oeltermann, A., Logothetis, N.K.
Most functional brain imaging studies use task-induced hemodynamic responses to infer underlying changes in neuronal activity. In addition to increases in cerebral blood flow and blood oxygenation...
Simultaneous EEG and fMRI in the macaque monkey at 4.7 Tesla (2006)
Schmid, M.C., Oeltermann, A., Juchem, C., Smirnakis, S.M., Logothetis, N.K.
Simultaneous electroencephalography (EEG)/functional magnetic resonance imaging (fMRI) acquisition can identify the brain networks involved in generating specific EEG patterns. Yet, the combination...
Nielsen, K., Logothetis, N.K., Rainer, G.
Neurons in the inferior temporal (IT) cortex respond selectively to complex objects, and maintain their selectivity despite partial occlusion. However, relatively little is known about how the...
Discrimination strategies of human and monkey for complex visual displays (2006)
Nielsen, K.J., Logothetis, N.K., Rainer, G.
By learning to discriminate among visual stimuli, human observers can become experts at specific visual tasks. The same is true for Rhesus monkeys, the major animal model of human visual perception....
Tracing neural circuits in vivo with Mn-enhanced MRI (2006)
Murayama, Y., Weber, B., Kadharbatcha, S.S., Augath, M., Logothetis, N.K.
The application of MRI-visible paramagnetic tracers to reveal in vivo connectivity can provide important subject-specific information for multisite, multielectrode intracortical recordings in...
Kourtzi, Z., Augath, M., Logothetis, N.K., Movshon, A., Kiorpes, L.
We studied the development of visual activation longitudinally in two infant monkeys aged 103561 days using the BOLD fMRI technique under opiate anesthesia and compared the results with those...
Local field potential reflects perceptual suppression in monkey visual cortex (2006)
Wilke, M., Logothetis, N.K., Leopold, D.A.
Neurophysiological and functional imaging experiments remain in apparent disagreement on the role played by the earliest stages of the visual cortex in supporting a visual percept. Here, we report...
Combined Passive and Active Shimming for In Vivo MR Spectroscopy at High Magnetic Field (2006)
Juchem, C., Mueller-Bierl, B., Schick, F., Logothetis, N.K., Pfeuffer, J.
The effect of artifacts on dependence measurement in fMRI (2006)
Gretton, A., Belitski, A., Murayama, Y., Schölkopf, B., Logothetis, N.K.
Vision: Stimulating Your Attention (2006)
Attentional selection biases the processing of higher visual areas to particular parts of a scene. Recent experiments show how stimulation of neurons in the frontal eye fields can mimic this process.
Fixations in natural scenes: interaction of image structure and image content (2006)
Kayser, C., Nielsen, K.J., Logothetis, N.K.
Explorative eye movements specifically target some parts of a scene while ignoring others. Here we investigate how local image structure - defined by spatial frequency contrast - and informative...
Lack of long-term cortical reorganization after macaque retinal lesions. (2005)
Smirnakis, S.M., Brewer, A.A., Schmid, M.C., Tolias, A.S., Schüz, A., Augath, M., ...
Several aspects of cortical organization are thought to remain plastic into adulthood, allowing cortical sensorimotor maps to be modified continuously by experience. This dynamic nature of cortical...
Integration of touch and sound in auditory cortex. (2005)
Kayser, C., Petkov, C., Augath, M., Logothetis, N.K.
To form a coherent percept of the environment, our brain combines information from different senses. Such multisensory integration occurs in higher association cortices; but supposedly it also occurs...
Mechanisms for allocating auditory attention: an auditory saliency map (2005)
Kayser, C., Petkov, C., Lippert, M., Logothetis, N.K.
Our nervous system is confronted with a barrage of sensory stimuli, but neural resources are limited and not all stimuli can be processed to the same extent. Mechanisms exist to bias attention...
Monkeys match the number of voices they hear to the number of faces they see (2005)
Jordan, K.E., Brannon, E.M., Logothetis, N.K., Ghazanfar, A.A.
Neurons in macaque area V4 acquire directional tuning after adaptation to motion stimuli (2005)
Tolias, A., Keliris, G., Smirnakis, S.M., Logothetis, N.K.
Macaque area V4 neurons are generally not selective for direction of motion, as judged from their response to directional stimuli presented after a baseline condition devoid of movement (classical...
Zappe, A.C., Merkle, H., Logothetis, N.K., Pfeuffer, J.
CASL experiments in the monkey brain were performed at 4.7 T and 7 T using a separate labeling coil. Increased sensitivity and SNR were achieved by a custom-made three-coil setup and high magnetic...
Juchem, C., Schick, F., Logothetis, N.K., Pfeuffer, J.
High magnetic fields increase the sensitivity and spectral dispersion in magnetic resonance spectroscopy (MRS). In contrast, spectral peaks are broadened in vivo at higher field strength due to...
A binocular rivalry study of motion perception in the human brain (2005)
Moutoussis, K., Keliris, G.A., Kourtzi, Z., Logothetis, N.K.
Pfeuffer, J., Merkle, H., Logothetis, N.K.
The first high-resolution CBF maps in the Macaca mulatta are shown that were obtained with 500 m in-plane resolution (single-shot GE-FAIR). High sensitivity was achieved by using a 7 T system...
Neuroscience: Rewiring the adult brain (Reply). (2005)
Smirnakis, S.M., Schmid, M.C., Brewer, A.A., Tolias, A.S., Schüz, A., Augath, M.A., ...
We disagree with Calford et al. that there is a consensus on adult plasticity in primate V1 cortex: for example, macaque area V1 cytochrome oxidase levels remained depressed for several months after...
Design, synthesis and characterization of new smart MR contrast agents sensitive to pH (2005)
Mishra, A.K., Pfeuffer, J., Mishra, A., Logothetis, N.K.
New gadolinium-based MR contrast agents Gd-DO3A-EP (-phosphono-ethyl) and Gd-DO3A-EPE (diethyl-phosphano-ethyl) were designed and synthesized to trace physiological changes of pH and calcium...
Mishra, A., Pfeuffer, J., Mishra, R., Logothetis, N.K., Mishra, A.K.
Smart MR contrast agents are chelated paramagnetic molecules, whose relaxivity changes as a function of their chemical environment (e.g. changes in pH, calcium or neurotransmitter concentration). The...
Localized 1H MR spectroscopy in the alert monkey at 7 Tesla (2005)
Pfeuffer, J., Juchem, C., Merkle, H., Logothetis, N.K.
Localized 1H MRS in alert monkeys was performed in a vertical 7T/60cm MR system utilizing increased sensitivity and spectral dispersion gained at high field. Refinements of acquisition and correction...
Kernel Constrained Covariance for Dependence Measurement (2005)
Gretton, A., Smola, A.J., Bousquet, O., Herbrich, R., Belitski, A., Augath, M., ...
We discuss reproducing kernel Hilbert space (RKHS)-based measures of statistical dependence, with emphasis on constrained covariance (COCO), a novel criterion to test dependence of random variables....
High-resolution 1H chemical shift imaging in the monkey visual cortex (2005)
Juchem, C., Logothetis, N.K., Pfeuffer, J.
Functionally distinct anatomic subdivisions of the brain can often be only a few millimeters in one or more dimensions. The study of metabolic differences in such structures by means of localized in...
Zappe,A.C., Merkle,H., Logothetis,N.K., Pfeuffer,J.
Arterial spin labeling is commonly used to measure cerebral blood flow (CBF) in the brain. Since CBF signal is intrinsically low, optimization of the signal-to-noise ratio (SNR) is critical. CASL...
Pfeuffer,J., Merkle,H., Logothetis,N.K.
Obtaining functional CBF maps with high spatial resolution is challenging, because the CBF signal is intrinsically low and the signal-to-noise is critical. Here we report the first high-resolution...
Localized 1H spectroscopy in the primary visual cortex V1 (2004)
Juchem,C., Merkle,H., Logothetis,N.K., Pfeuffer,J.
The primary visual cortex V1 is the elementary target, when visual function and cortical reorganization are investigated. The study demonstrates that online analysis of field distributions is helpful...
In vivo CSI of glutamate in the monkey brain (2004)
Juchem,C., Merkle,H., Logothetis,N.K., Pfeuffer,J.
CSI studies of metabolites in the human brain typically suffer from poor spatial resolution or they are restricted to substances with strong peaks that are visible at longer echo times. In this...
Prediction on Spike Data Using Kernel Algorithms (2004)
Eichhorn,J., Tolias,A.S., Zien,A., Kuss,M., Rasmussen,C.E., Weston,J., ...
We report and compare the performance of different learning algorithms based on data from cortical recordings. The task is to predict the orientation of visual stimuli from the activity of a...
Modelling Spikes with Mixtures of Factor Analysers (2004)
Görür,D., Rasmussen,C.E., Tolias,A.S., Sinz,F., Logothetis,N.K.
Identifying the action potentials of individual neurons from extracellular recordings, known as spike sorting, is a challenging problem. We consider the spike sorting problem using a generative...
Pfeuffer,J., Steudel,T., Merkle,H., Logothetis,N.K.
Functional MR imaging in monkeys promises to build a bridge between brain research in humans and the large body of systems neuroscience work in animals. Simultaneous fMRI and electrophysiology was...
Zappe, A.C., Merkle, H., Logothetis, N.K., Pfeuffer, J.
Arterial spin labeling is commonly used to measure cerebral blood flow (CBF) in the brain. Since CBF signal is intrinsically low, optimization of the signal-to-noise ratio (SNR) is critical. CASL...
Pfeuffer, J., Merkle, H., Logothetis, N.K.
Obtaining functional CBF maps with high spatial resolution is challenging, because the CBF signal is intrinsically low and the signal-to-noise is critical. Here we report the first high-resolution...
Neural correlates of motion perception in the human visual brain (2004)
Moutoussis, K., Keliris, G.A., Kourtzi, Z., Logothetis, N.K.
Localized 1H spectroscopy in the primary visual cortex V1 (2004)
Juchem, C., Merkle, H., Logothetis, N.K., Pfeuffer, J.
The primary visual cortex V1 is the elementary target, when visual function and cortical reorganization are investigated. The study demonstrates that online analysis of field distributions is helpful...
In vivo CSI of glutamate in the monkey brain (2004)
Juchem, C., Merkle, H., Logothetis, N.K., Pfeuffer, J.
CSI studies of metabolites in the human brain typically suffer from poor spatial resolution or they are restricted to substances with strong peaks that are visible at longer echo times. In this...
Prediction on Spike Data Using Kernel Algorithms (2004)
Eichhorn, J., Tolias, A.S., Zien, A., Kuss, M., Rasmussen, C.E., Weston, J., ...
We report and compare the performance of different learning algorithms based on data from cortical recordings. The task is to predict the orientation of visual stimuli from the activity of a...
Modelling Spikes with Mixtures of Factor Analysers (2004)
Görür, D., Rasmussen, C.E., Tolias, A.S., Sinz, F., Logothetis, N.K., Rasmussen, C. E., ...
Identifying the action potentials of individual neurons from extracellular recordings, known as spike sorting, is a challenging problem. We consider the spike sorting problem using a generative...
Pfeuffer, J., Steudel, T., Merkle, H., Logothetis, N.K.
Functional MR imaging in monkeys promises to build a bridge between brain research in humans and the large body of systems neuroscience work in animals. Simultaneous fMRI and electrophysiology was...
Multisensory integration of looming signals by rhesus monkeys. (2004)
Maier, J.X., Neuhoff, J.G., Logothetis, N.K., Ghazanfar, A.A.
Integration of Local Features into Global Shapes: Monkey and Human fMRI Studies (2003)
Kourtzi,Z., Tolias,A.S., Altmann,C.F., Augath,M.A., Logothetis,N.K.
The integration of local image features into global shapes was investigated in monkeys and humans using fMRI. An adaptation paradigm was used, in which stimulus selectivity was deduced by changes in...
Negative BOLD Response Ipsi-lateral to the Visual Stimulus: Origin Is Not Blood Stealing (2003)
Shmuel,A., Augath,M.A., Rounis,E., Logothetis,N.K., Smirnakis,S.M.
The Negative BOLD Response in Monkey V1 is Associated with Decreases in Neuronal Activity (2003)
Shmuel,A., Augath,M.A., Oeltermann,A., Pauls,J., Murayama,Y., Logothetis,N.K.
The Negative BOLD Response in Monkey V1 is Associated with Decreases in Neuronal Activity (2003)
Shmuel,A., Augath,M.A., Oeltermann,A., Pauls,J., Logothetis,N.K.
Functional MR imaging of the awake monkey in a novel vertical large-bore 7 Tesla setup (2003)
Pfeuffer,J., Pauls,J., Augath,M.A., Steudel,T., Merkle,H., Logothetis,N.K.
First fMRI results in the awake trained monkey (Macaca mulatta) using a novel vertical 7T/60cm MR system are reported. The setup was custom-designed for MR imaging of monkeys in upright position and...
Proton MR Spectroscopy at 7 Tesla in the Macaque monkey (2003)
Pfeuffer,J., Juchem,C., Merkle,H., Logothetis,N.K.
First MR spectroscopy results in the anaesthetized and the awake trained monkey (Macaca mulatta) are reported using a novel vertical bore 7T/60cm MR system. The setup was custom-designed for MR...
In vivo CSI of glutamate in Macaca mulatta brain (2003)
Juchem,C., Merkle,H., Logothetis,N.K., Pfeuffer,J.
Glutamate is the main excitatory neurotransmitter in the CNS and plays together with glutamine an important role in brain physiology. A quantitative spatially resolved analysis of glutamate separate...
Perception of temporally interleaved ambiguous patterns (2003)
Maier,A., Wilke,M., Logothetis,N.K., Leopold,D.A.
Background: Continuous viewing of ambiguous patterns is characterized by wavering perception that alternates between two or more equally valid visual solutions. However, when such patterns are viewed...
Very slow activity fluctuations in monkey visual cortex: implications for functional imaging (2003)
Leopold,D.A., Murayama,Y., Logothetis,N.K.
We examined fluctuations in band-limited power (BLP) of local field potential (LFP) signals recorded from multiple electrodes in visual cortex of the monkey during different behavioral states. We...
Measuring subjective visual perception in the nonhuman primate (2003)
Leopold,D.A., Maier,A., Logothetis,N.K.
Understanding how activity in the brain leads to a subjective percept is of great interest to philosophers and neuroscientists alike. In the last years, neurophysiological experiments have approached...
Negative BOLD Response Ipsi-lateral to the Visual Stimulus: Origin Is Not Blood Stealing (2003)
Shmuel, A., Augath, M.A., Rounis, E., Logothetis, N.K., Smirnakis, S.M.
The Negative BOLD Response in Monkey V1 is Associated with Decreases in Neuronal Activity (2003)
Shmuel, A., Augath, M.A., Oeltermann, A., Pauls, J., Murayama, Y., Logothetis, N.K.
The Negative BOLD Response in Monkey V1 is Associated with Decreases in Neuronal Activity (2003)
Shmuel, A., Augath, M.A., Oeltermann, A., Pauls, J., Logothetis, N.K.
Functional MR imaging of the awake monkey in a novel vertical large-bore 7 Tesla setup (2003)
Pfeuffer, J., Pauls, J., Augath, M.A., Steudel, T., Merkle, H., Logothetis, N.K.
First fMRI results in the awake trained monkey (Macaca mulatta) using a novel vertical 7T/60cm MR system are reported. The setup was custom-designed for MR imaging of monkeys in upright position and...
Proton MR Spectroscopy at 7 Tesla in the Macaque monkey (2003)
Pfeuffer, J., Juchem, C., Merkle, H., Logothetis, N.K.
First MR spectroscopy results in the anaesthetized and the awake trained monkey (Macaca mulatta) are reported using a novel vertical bore 7T/60cm MR system. The setup was custom-designed for MR...
In vivo CSI of glutamate in Macaca mulatta brain (2003)
Juchem, C., Merkle, H., Logothetis, N.K., Pfeuffer, J.
Glutamate is the main excitatory neurotransmitter in the CNS and plays together with glutamine an important role in brain physiology. A quantitative spatially resolved analysis of glutamate separate...
Neural mechanisms of perceptual organization (2003)
Logothetis, N.K., Leopold, D.A., Sheinberg, D.L., Naoyuki, O.
Perception of temporally interleaved ambiguous patterns (2003)
Maier, A., Wilke, M., Logothetis, N.K., Leopold, D.A.
Background: Continuous viewing of ambiguous patterns is characterized by wavering perception that alternates between two or more equally valid visual solutions. However, when such patterns are viewed...
Very slow activity fluctuations in monkey visual cortex: implications for functional imaging (2003)
Leopold, D.A., Murayama, Y., Logothetis, N.K.
We examined fluctuations in band-limited power (BLP) of local field potential (LFP) signals recorded from multiple electrodes in visual cortex of the monkey during different behavioral states. We...
Measuring subjective visual perception in the nonhuman primate (2003)
Leopold, D.A., Maier, A., Logothetis, N.K., Anthony, J., Roepstorff, A.
Understanding how activity in the brain leads to a subjective percept is of great interest to philosophers and neuroscientists alike. In the last years, neurophysiological experiments have approached...
Integration of Local Features into Global Shapes: Monkey and Human fMRI Studies (2003)
Kourtzi, Z., Tolias, A.S., Altmann, C.F., Augath, M.A., Logothetis, N.K.
The integration of local image features into global shapes was investigated in monkeys and humans using fMRI. An adaptation paradigm was used, in which stimulus selectivity was deduced by changes in...
Ultra-High Resolution fMRI in Monkeys with Implanted RF Coils. (2002)
Logothetis,N.K., Merkle,H., Augath,M.A., Trinath,T., Ugurbil,K.
Magnetic Resonance Imaging of Neuronal Connections in the Macaque Monkey (2002)
Saleem,K.S., Pauls,J., Augath,M.A., Trinath,T., Prause,B.A., Hashikawa,T., ...
Recently, an MRI-detectable, neuronal tract-tracing method in living animals was introduced that exploits the anterograde transport of manganese (Mn2+). We present the results of experiments...
Binocular rivalry the alternations in perception that occur when different images are presented to the two eyes has been the subject of intensive investigation for more than 160 years. The...
Stable Perception of Visually Ambiguous Patterns (2002)
Leopold,D.A., Wilke,M., Maier,A., Logothetis,N.K.
During the viewing of certain patterns, widely known as ambiguous or puzzle figures, perception lapses into a sequence of spontaneous alternations, switching every few seconds between two or more...
Leopold,D.A., Plettenberg,H.K., Logothetis,N.K.
We used optokinetic responses and functional magnetic resonance imaging (fMRI) to examine visual processing in monkeys whose conscious state was modulated by low doses (1-2 mg/kg) of the dissociative...
Magnetic Resonance Imaging of Neuronal Connections in the Macaque Monkey (2002)
Saleem, K.S., Pauls, J., Augath, M.A., Trinath, T., Prause, B.A., Hashikawa, T., ...
Recently, an MRI-detectable, neuronal tract-tracing method in living animals was introduced that exploits the anterograde transport of manganese (Mn2+). We present the results of experiments...
Binocular rivalry the alternations in perception that occur when different images are presented to the two eyes has been the subject of intensive investigation for more than 160 years. The...
Ultra-High Resolution fMRI in Monkeys with Implanted RF Coils. (2002)
Logothetis, N.K., Merkle, H., Augath, M.A., Trinath, T., Ugurbil, K.
Stable Perception of Visually Ambiguous Patterns (2002)
Leopold, D.A., Wilke, M., Maier, A., Logothetis, N.K.
During the viewing of certain patterns, widely known as ambiguous or puzzle figures, perception lapses into a sequence of spontaneous alternations, switching every few seconds between two or more...
Leopold, D.A., Plettenberg, H.K., Logothetis, N.K.
We used optokinetic responses and functional magnetic resonance imaging (fMRI) to examine visual processing in monkeys whose conscious state was modulated by low doses (1-2 mg/kg) of the dissociative...
On the Physiology of Bistable Percepts. (1998)
Logothetis, N. K., Leopold, D. A.
Binocular rivalry refers to the alternating perceptions experienced when two dissimilar patterns are stereoscopically viewed. To study the neural mechanism that underlies such competitive...
The Role of Attention in Binocular Rivalry as Revealed through Optokinetic Nystagmus. (1997)
Leopold, D. A., Fitzgibbons, J. C., Logothetis, N. K.
When stimuli presented to the two eyes differ considerably, stable binocular fusion fails, and the subjective percept alternates between the two monocular images, a phenomenon known as binocular...
On the Physiology of Bistable Percepts (1995)
Logothetis, N.K., Leopold, D.A.
Binocular rivalry refers to the alternating perceptions experienced when two dissimilar patterns are stereoscopically viewed. To study the neural mechanism that underlies such competitive...
The Role of Attention in Binocular Rivalry as Revealed Through Optokinetic Nystagmus (1995)
Leopold, D.A., Fitzgibbons, J.C., Logothetis, N.K.
When stimuli presented to the two eyes differ considerably, stable binocular fusion fails, and the subjective percept alternates between the two monocular images, a phenomenon known as binocular...
The Role of Attention in Binocular Rivalry as Revealed Through Optokinetic Nystagmus (1995)
Leopold, D.A., Fitzgibbons, J.C., Logothetis, N.K.
When stimuli presented to the two eyes differ considerably, stable binocular fusion fails, and the subjective percept alternates between the two monocular images, a phenomenon known as binocular...
On the Physiology of Bistable Percepts (1995)
Logothetis, N.K., Leopold, D.A.
Binocular rivalry refers to the alternating perceptions experienced when two dissimilar patterns are stereoscopically viewed. To study the neural mechanism that underlies such competitive...
Spatial Reference Frames for Object Recognition: Tuning for Rotations in Depth (1995)
Logothetis, N.K., Pauls, J., Poggio, T.
The inferior temporal cortex (IT) of monkeys is thought to play an essential role in visual object recognition. Inferotemporal neurons are known to respond to complex visual stimuli, including...
Spatial Reference Frames for Object Recognition: Tuning for Rotations in Depth (1995)
Logothetis, N.K., Pauls, J., Poggio, T.
The inferior temporal cortex (IT) of monkeys is thought to play an essential role in visual object recognition. Inferotemporal neurons are known to respond to complex visual stimuli, including...
Spatial reference frames for object recognition - tuning for rotations in depth (1995)
N. K. Logothetis, J. Pauls, T. Poggio
This publication can be retrieved by anonymous ftp to publications.ai.mit.edu. The inferior temporal cortex (IT) of monkeys is thought toplay an essential role in visual object recognition....
The Role of Attention in Binocular Rivalry as Revealed through Optokinetic Nystagmus (1995)
D. A. Leopold, J. C. Fitzgibbons, N. K. Logothetis
When stimuli presented to the two eyes differ considerably, stable binocular fusion fails, and the subjective percept alternates between the two monocular images, a phenomenon known as binocular...
Spatial Reference Frames for Object Recognition Tuning for Rotations in Depth (1995)
N. K. Logothetis, J. Pauls, T. Poggio
The inferior temporal cortex (IT) of monkeys is thought to play an essential role in visual object recognition. Inferotemporal neurons are known to respond to complex visual stimuli, including...
On the Physiology of Bistable Percepts (1995)
N. K. Logothetis, D. A. Leopold
Binocular rivalry refers to the alternating perceptions experienced when two dissimilar patterns are stereoscopically viewed. To study the neural mechanism that underlies such competitive...
Viewer-Centered Object Recognition in Monkeys (1994)
Logothetis, N.K., Pauls, J., Poggio, T.
How does the brain recognize three-dimensional objects? We trained monkeys to recognize computer rendered objects presented from an arbitrarily chosen training view, and subsequently tested their...
Viewer-Centered Object Recognition in Monkeys (1994)
Logothetis, N.K., Pauls, J., Poggio, T.
How does the brain recognize three-dimensional objects? We trained monkeys to recognize computer rendered objects presented from an arbitrarily chosen training view, and subsequently tested their...
View-dependent object recognition by monkeys (1994)
N. K. Logothetis, J. Pauls, T. Poggio
How does the brain recognize three-dimensional objects? An initial step towards the understanding of the neural substrate of visual object recognition can be taken by studying rst the nature of...
Viewer-Centered Object Recognition in Monkeys (1994)
N. K. Logothetis, J. Pauls, T. Poggio
How does the brain recognize three-dimensional objects? An initial step towards the understanding of the neural substrate of visual object recognition can be taken by studying first the nature of...
The role of temporal cortical areas in perceptual organization
Sheinberg, D. L., Logothetis, N. K.
The visual areas of the temporal lobe of the primate are thought to be essential for the representation of visual objects. To examine the role of these areas in the visual awareness of a stimulus, we...
The role of temporal cortical areas in perceptual organization
Sheinberg, D. L., Logothetis, N. K.
The visual areas of the temporal lobe of the primate are thought to be essential for the representation of visual objects. To examine the role of these areas in the visual awareness of a stimulus, we...
Single units and conscious vision.
Figures that can be seen in more than one way are invaluable tools for the study of the neural basis of visual awareness, because such stimuli permit the dissociation of the neural responses that...
The Influence of Moderate Hypercapnia on Neural Activity in the Anesthetized Nonhuman Primate
Zappe, A.C., Uludağ, K., Oeltermann, A., Uğurbil, K., Logothetis, N.K.
Hypercapnia is often used as vasodilatory challenge in clinical applications and basic research. In functional magnetic resonance imaging (fMRI), elevated CO2 is applied to derive stimulus-induced...
Cortical mechanisms of sensory learning and object recognition
Hoffman, K.L., Logothetis, N.K.
Learning about the world through our senses constrains our ability to recognise our surroundings. Experience shapes perception. What is the neural basis for object recognition and how are...