Publications - Salk Institute for Biological Studies

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Pawar, A.S., Gepshtein, S., Savel'ev, S., Albright, T.D. Mechanisms of Spatiotemporal Selectivity in Cortical Area MT. (2018) Neuron. DOI: 10.1016/j.neuron.2018.12.002

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Kafaligonul, H., Albright, T.D., Stoner, G.R. Auditory modulation of spiking activity and local field potentials in area MT does not appear to underlie an audiovisual temporal illusion. (2018) Journal of Neurophysiology. DOI: 10.1152/jn.00835.2017

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Bell, S., Sah, S., Albright, T.D., Gates, S.J., Denton, M.B., Casadevall, A. A call for more science in forensic science. (2018) Proceedings of the National Academy of Sciences of the United States of America. DOI: 10.1073/pnas.1712161115

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Gepshtein, S., Albright, T.D. Adaptive Optimization of Visual Sensitivity. (2017) J Indian Inst Sci. 97(4):423-434. DOI: 10.1007/s41745-017-0056-y

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Albright, T.D. Why eyewitnesses fail. (2017) Proceedings of the National Academy of Sciences of the United States of America. DOI: 10.1073/pnas.1706891114

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Saks, M.J., Albright, T., Bohan, T.L., Bierer, B.E., Bowers, C.M., Bush, M.A., Bush, P.J., Casadevall, A., Cole, S.A., Denton, M.B., Diamond, S.S., Dioso-Villa, R., Epstein, J., Faigman, D., Faigman, L., Fienberg, S.E., Garrett, B.L., Giannelli, P.C., Greely, H.T., Imwinkelried, E., Jamieson, A., Kafadar, K., Kassirer, J.P., Koehler, J.'., Korn, D., Mnookin, J., Morrison, A.B., Murphy, E., Peerwani, N., Peterson, J.L., Risinger, D.M., Sensabaugh, G.F., Spiegelman, C., Stern, H., Thompson, W.C., Wayman, J.L., Zabell, S., Zumwalt, R.E. Forensic bitemark identification: weak foundations, exaggerated claims. (2016) J Law Biosci. 3(3):538-575. DOI: 10.1093/jlb/lsw045

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Lesmes, L.A., Lu, Z.L., Baek, J., Tran, N., Dosher, B.A., Albright, T.D. Developing Bayesian adaptive methods for estimating sensitivity thresholds (d') in Yes-No and forced-choice tasks. (2015) Frontiers in Psychology. 6:1070. DOI: 10.3389/fpsyg.2015.01070

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Albright, T.D. Travels with Charlie. (2014) Journal of Cognitive Neuroscience. 26(6):1305-23. DOI: 10.1162/jocn_a_00627

Gil-da-Costa, R., Stoner, G.R., Fung, R., Albright, T.D. Nonhuman primate model of schizophrenia using a noninvasive EEG method. (2013) Proceedings of the National Academy of Sciences of the United States of America. 110(38):15425-30. DOI: 10.1073/pnas.1312264110

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Ruiz, O., Lustig, B.R., Nassi, J.J., Cetin, A., Reynolds, J.H., Albright, T.D., Callaway, E.M., Stoner, G.R., Roe, A.W. Optogenetics through windows on the brain in the nonhuman primate. (2013) Journal of Neurophysiology. 110(6):1455-67. DOI: 10.1152/jn.00153.2013

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Ponce-Alvarez, A., Thiele, A., Albright, T.D., Stoner, G.R., Deco, G. Stimulus-dependent variability and noise correlations in cortical MT neurons. (2013) Proceedings of the National Academy of Sciences of the United States of America. 110(32):13162-7. DOI: 10.1073/pnas.1300098110

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Richert, M., Albright, T.D., Krekelberg, B. The complex structure of receptive fields in the middle temporal area. (2013) Frontiers in Systems Neuroscience. 7:2. DOI: 10.3389/fnsys.2013.00002

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Gepshtein, S., Lesmes, L.A., Albright, T.D. Sensory adaptation as optimal resource allocation. (2013) Proceedings of the National Academy of Sciences of the United States of America. 110(11):4368-73. DOI: 10.1073/pnas.1204109110

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Albright, T.D. On the perception of probable things: neural substrates of associative memory, imagery, and perception. (2012) Neuron. 74(2):227-45. DOI: 10.1016/j.neuron.2012.04.001

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Chen, X., Hoffmann, K.P., Albright, T.D., Thiele, A. Effect of feature-selective attention on neuronal responses in macaque area MT. (2012) Journal of Neurophysiology. 107(5):1530-43. DOI: 10.1152/jn.01042.2010

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Attention influences visual processing in striate and extrastriate cortex, which has been extensively studied for spatial-, object-, and feature-based attention. Most studies exploring neural signatures of feature-based attention have trained animals to attend to an object identified by a certain feature and ignore objects/displays identified by a different feature. Little is known about the effects of feature-selective attention, where subjects attend to one stimulus feature domain (e.g., color) of an object while features from different domains (e.g., direction of motion) of the same object are ignored. To study this type of feature-selective attention in area MT in the middle temporal sulcus, we trained macaque monkeys to either attend to and report the direction of motion of a moving sine wave grating (a feature for which MT neurons display strong selectivity) or attend to and report its color (a feature for which MT neurons have very limited selectivity). We hypothesized that neurons would upregulate their firing rate during attend-direction conditions compared with attend-color conditions. We found that feature-selective attention significantly affected 22% of MT neurons. Contrary to our hypothesis, these neurons did not necessarily increase firing rate when animals attended to direction of motion but fell into one of two classes. In one class, attention to color increased the gain of stimulus-induced responses compared with attend-direction conditions. The other class displayed the opposite effects. Feature-selective activity modulations occurred earlier in neurons modulated by attention to color compared with neurons modulated by attention to motion direction. Thus feature-selective attention influences neuronal processing in macaque area MT but often exhibited a mismatch between the preferred stimulus dimension (direction of motion) and the preferred attention dimension (attention to color).

Hartmann, T.S., Bremmer, F., Albright, T.D., Krekelberg, B. Receptive field positions in area MT during slow eye movements. (2011) Journal of Neuroscience. 31(29):10437-44. DOI: 10.1523/JNEUROSCI.5590-10.2011

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Lesmes, L.A., Lu, Z.L., Baek, J., Albright, T.D. Bayesian adaptive estimation of the contrast sensitivity function: the quick CSF method. (2010) Journal of Vision. 10(3):17.1-21. DOI: 10.1167/10.3.17

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Buracas, G.T., Albright, T.D. Modulation of neuronal responses during covert search for visual feature conjunctions. (2009) Proceedings of the National Academy of Sciences of the United States of America. 106(39):16853-8. DOI: 10.1073/pnas.0908455106

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Huang, X., Albright, T.D., Stoner, G.R. Stimulus dependency and mechanisms of surround modulation in cortical area MT. (2008) Journal of Neuroscience. 28(51):13889-906. DOI: 10.1523/JNEUROSCI.1946-08.2008

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Schlack, A., Krekelberg, B., Albright, T.D. Speed perception during acceleration and deceleration. (2008) Journal of Vision. 8(8):9.1-11. DOI: 10.1167/8.8.9

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Schlack, A., Krekelberg, B., Albright, T.D. Recent history of stimulus speeds affects the speed tuning of neurons in area MT. (2007) Journal of Neuroscience. 27(41):11009-18. DOI: 10.1523/JNEUROSCI.3165-07.2007

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Horwitz, G.D., Chichilnisky, E.J., Albright, T.D. Cone inputs to simple and complex cells in V1 of awake macaque. (2007) Journal of Neurophysiology. 97(4):3070-81. DOI: 10.1152/jn.00965.2006

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Schlack, A., Albright, T.D. Remembering visual motion: neural correlates of associative plasticity and motion recall in cortical area MT. (2007) Neuron. 53(6):881-90. DOI: 10.1016/j.neuron.2007.02.028

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Huang, X., Albright, T.D., Stoner, G.R. Adaptive surround modulation in cortical area MT. (2007) Neuron. 53(5):761-70. DOI: 10.1016/j.neuron.2007.01.032

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Krekelberg, B., van Wezel, R.J., Albright, T.D. Interactions between speed and contrast tuning in the middle temporal area: implications for the neural code for speed. (2006) Journal of Neuroscience. 26(35):8988-98. DOI: 10.1523/JNEUROSCI.1983-06.2006

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Tan, E.M., Yamaguchi, Y., Horwitz, G.D., Gosgnach, S., Lein, E.S., Goulding, M., Albright, T.D., Callaway, E.M. Selective and quickly reversible inactivation of mammalian neurons in vivo using the Drosophila allatostatin receptor. (2006) Neuron. 51(2):157-70. DOI: 10.1016/j.neuron.2006.06.018

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Krekelberg, B., van Wezel, R.J., Albright, T.D. Adaptation in macaque MT reduces perceived speed and improves speed discrimination. (2006) Journal of Neurophysiology. 95(1):255-70. DOI: 10.1152/jn.00750.2005

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Messinger, A., Squire, L.R., Zola, S.M., Albright, T.D. Neural correlates of knowledge: stable representation of stimulus associations across variations in behavioral performance. (2005) Neuron. 48(2):359-71. DOI: 10.1016/j.neuron.2005.08.035

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van der Smagt, M.J., Wehrhahn, C., Albright, T.D. Contextual masking of oriented lines: interactions between surface segmentation cues. (2005) Journal of Neurophysiology. 94(1):576-89. DOI: 10.1152/jn.00366.2004

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Horwitz, G.D., Albright, T.D. Paucity of chromatic linear motion detectors in macaque V1. (2005) Journal of Vision. 5(6):525-33. DOI: 10.1167/5.6.4

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Krekelberg, B., Albright, T.D. Motion mechanisms in macaque MT. (2005) Journal of Neurophysiology. 93(5):2908-21. DOI: 10.1152/jn.00473.2004

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The macaque middle temporal area (MT) is exquisitely sensitive to visual motion and there is a large amount of evidence that neural activity in MT is tightly correlated with the perception of motion. The mechanisms by which MT neurons achieve their directional selectivity, however, have received considerably less attention. We investigated the motion-energy model as a description of motion mechanisms in macaque MT. We first confirmed one of the predictions of the motion-energy model; macaques-just like humans-perceive a reversed direction of motion when a stimulus reverses contrast with every displacement (reverse-phi). This reversal of perceived direction had a clear correlate in the neural responses of MT cells, which were predictive of the monkey's behavioral decisions. Second, we investigated how multiple motion-energy components are combined. Psychophysical data have been used to argue that motion-energy components representing opposite directions are subtracted from each other. Our data show, however, that the interactions among motion-energy components are more complex. In particular, we found that the influence of a given component on the response to a stimulus consisting of multiple components depends on factors other than the response to that component alone. This suggests that there are subthreshold nonlinear interactions among multiple motion-energy components; these could take place within MT or in earlier stages of the motion network such as V1. We propose a model that captures the complexity of these component interactions by means of a competitive interaction among the components. This provides a better description of the MT responses than the subtractive motion opponency envisaged in the motion-energy model, even when the latter is combined with a gain-control mechanism. The competitive interaction extends the dynamic range of the cells and allows them to provide information on more subtle changes in motion patterns, including changes that are not purely directional.

Lein, E.S., Callaway, E.M., Albright, T.D., Gage, F.H. Redefining the boundaries of the hippocampal CA2 subfield in the mouse using gene expression and 3-dimensional reconstruction. (2005) Journal of Comparative Neurology. 485(1):1-10. DOI: 10.1002/cne.20426

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Horwitz, G.D., Chichilnisky, E.J., Albright, T.D. Blue-yellow signals are enhanced by spatiotemporal luminance contrast in macaque V1. (2005) Journal of Neurophysiology. 93(4):2263-78. DOI: 10.1152/jn.00743.2004

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Hegdé, J., Albright, T.D., Stoner, G.R. Second-order motion conveys depth-order information. (2004) Journal of Vision. 4(10):838-42. DOI: 10.1167/4.10.1

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Schwartz, O., Movellan, J.R., Wachtler, T., Albright, T.D., Sejnowski, T.J. Spike count distributions, factorizability, and contextual effects in area V1. (2004) Neurocomputing. 58-60:893-900. DOI: 10.1016/j.neucom.2004.01.143

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Horwitz, G.D., Albright, T.D. Short-latency fixational saccades induced by luminance increments. (2003) Journal of Neurophysiology. 90(2):1333-9. DOI: 10.1152/jn.00146.2003

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Diogo, A.C., Soares, J.G., Koulakov, A., Albright, T.D., Gattass, R. Electrophysiological imaging of functional architecture in the cortical middle temporal visual area of Cebus apella monkey. (2003) Journal of Neuroscience. 23(9):3881-98.

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Wachtler, T., Sejnowski, T.J., Albright, T.D. Representation of color stimuli in awake macaque primary visual cortex. (2003) Neuron. 37(4):681-91.

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Movshon, J.A., Albright, T.D., Stoner, G.R., Majaj, N.J., Smith, M.A. Cortical responses to visual motion in alert and anesthetized monkeys. (2003) Nature Neuroscience. 6(1):3; author reply 3-4. DOI: 10.1038/nn0103-3a

Diogo, A.C., Soares, J.G., Albright, T.D., Gattass, R. Two-dimensional map of direction selectivity in cortical visual area MT of Cebus monkey. (2002) An. Acad. Bras. Cienc. 74(3):463-76.

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Albright, T.D., Stoner, G.R. Contextual influences on visual processing. (2002) Annual Review of Neuroscience. 25:339-79. DOI: 10.1146/annurev.neuro.25.112701.142900

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Thiele, A., Dobkins, K.R., Albright, T.D. Neural correlates of chromatic motion perception. (2001) Neuron. 32(2):351-8.

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Messinger, A., Squire, L.R., Zola, S.M., Albright, T.D. Neuronal representations of stimulus associations develop in the temporal lobe during learning. (2001) Proceedings of the National Academy of Sciences of the United States of America. 98(21):12239-44. DOI: 10.1073/pnas.211431098

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Wachtler, T., Albright, T.D., Sejnowski, T.J. Nonlocal interactions in color perception: nonlinear processing of chromatic signals from remote inducers. (2001) Vision Research. 41(12):1535-46.

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Albright, T.D., Jessell, T.M., Kandell, E.R., Posner, M.I. Progress in the neural sciences in the the century after Cajal (and the mysteries that remain). (2001) Ann. N. Y. Acad. Sci. 929:11-40.

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Albright, T.D., Kandel, E.R., Posner, M.I. Cognitive neuroscience. (2000) Current Opinion in Neurobiology. 10(5):612-24.

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Duncan, R.O., Albright, T.D., Stoner, G.R. Occlusion and the interpretation of visual motion: perceptual and neuronal effects of context. (2000) Journal of Neuroscience. 20(15):5885-97.

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Thiele, A., Dobkins, K.R., Albright, T.D. Neural correlates of contrast detection at threshold. (2000) Neuron. 26(3):715-24.

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Dobkins, K.R., Thiele, A., Albright, T.D. Comparison of red-green equiluminance points in humans and macaques: evidence for different L:M cone ratios between species. (2000) J Opt Soc Am A Opt Image Sci Vis. 17(3):545-56.

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The human spectral luminosity function (V(lambda)) can be modeled as the linear sum of signals from long-wavelength-selective (L) and middle-wavelength-selective (M) cones, with L cones being weighted by a factor of approximately 2. This factor of approximately 2 is thought to reflect an approximate 2:1 ratio of L:M cones in the human retina, which has been supported by studies that allow for more direct counting of different cone types in the retina. In contrast to humans, several lines of retinally based evidence in macaques suggest an L:M ratio closer to 1:1. To investigate the consequences of differences in L:M cone ratios between humans and macaques, red-green equiluminance matches obtained psychophysically in humans (n = 11) were compared with those obtained electrophysiologically from single neurons in the extrastriate middle temporal visual area of macaques (M. mulatta, n = 5). Neurons in the middle temporal visual area were tested with sinusoidal red-green moving gratings across a range of luminance contrasts, with equiluminance being defined as the red-green contrast yielding a response minimum. Human subjects were tested under analogous conditions, by a minimally distinct motion technique, to establish psychophysical equiluminance. Although red-green equiluminance points in both humans and macaques were found to vary across individuals, the means across species differed significantly; compared with humans, macaque equiluminance points reflected relatively greater sensitivity to green. By means of a simple model based on equating the weighted sum of L and M cone signals, the observed red-green equiluminance points were found to be consistent with L:M cone ratios of approximately 2:1 in humans and 1:1 in macaques. These data thus support retinally based estimates of L:M cone ratios and further demonstrate that the information carried in the cone mosaic has functional consequences for red-green spectral sensitivity revealed perceptually and in the dorsal stream of visual cortex.

Albright, T.D., Jessell, T.M., Kandel, E.R., Posner, M.I. Neural science: a century of progress and the mysteries that remain. (2000) Neuron. 25 Suppl:S1-55.

Albright, T.D., Jessell, T.M., Kandel, E.R., Posner, M.I. Neural science: a century of progress and the mysteries that remain. (2000) Cell. 100 Suppl:S1-55.

Croner, L.J., Albright, T.D. Seeing the big picture: integration of image cues in the primate visual system. (1999) Neuron. 24(4):777-89.

Thiele, A., Dobkins, K.R., Albright, T.D. The contribution of color to motion processing in Macaque middle temporal area. (1999) Journal of Neuroscience. 19(15):6571-87.

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Albright, T.D. More than one way to see it move? (1999) Proceedings of the National Academy of Sciences of the United States of America. 96(14):7611-3.

Buracas, G.T., Albright, T.D. Gauging sensory representations in the brain. (1999) Trends in Neurosciences. 22(7):303-9.

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Buracas, G.T., Albright, T.D. Covert visual search: a comparison of performance by humans and macaques (Macaca mulatta). (1999) Behavioral Neuroscience. 113(3):451-64.

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Croner, L.J., Albright, T.D. Segmentation by color influences responses of motion-sensitive neurons in the cortical middle temporal visual area. (1999) Journal of Neuroscience. 19(10):3935-51.

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Buracas, G.T., Zador, A.M., DeWeese, M.R., Albright, T.D. Efficient discrimination of temporal patterns by motion-sensitive neurons in primate visual cortex. (1998) Neuron. 20(5):959-69.

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Stoner, G.R., Albright, T.D. Luminance contrast affects motion coherency in plaid patterns by acting as a depth-from-occlusion cue. (1998) Vision Research. 38(3):387-401.

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Dobkins, K.R., Stoner, G.R., Albright, T.D. Perceptual, oculomotor, and neural responses to moving color plaids. (1998) Perception. 27(6):681-709. DOI: 10.1068/p270681

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Moving plaids constructed from two achromatic gratings of identical luminance contrast are known to yield a percept of coherent pattern motion, as are plaids constructed from two identical chromatic (e.g. isoluminant red/green) gratings. To examine the interactive influences of chromatic and luminance contrast on the integration of visual motion signals, we constructed plaids with gratings that possessed both forms of contrast. We used plaids of two basic types, which differed with respect to the phase relationship between chromatic and luminance modulations (after Kooi et al, 1992 Perception 21 583-598). One plaid type ('symmetric') was made from component gratings that had identical chromatic/luminance phase relationships (e.g. both components were red-bright/green-dark modulation). The second plaid type ('asymmetric') was made from components that had complimentary phase relationships (i.e. one red-bright/green-dark grating and one green-bright/red-dark grating). Human subjects reported that the motion of symmetric plaids was perceptually coherent, while the components of asymmetric plaids failed to cohere. We also recorded eye movements elicited by both types of plaids to determine if they are similarly affected by these image cues for motion coherence. Results demonstrate that, under many conditions, eye movements elicited by perceptually coherent vs noncoherent plaids are distinguishable from one another. To reveal the neural bases of these perceptual and oculomotor phenomena, we also recorded the responses of neurons in the middle temporal visual area (area MT) of macaque visual cortex. Here we found that individual neurons exhibited differential tuning to symmetric vs asymmetric plaids. These neurophysiological results demonstrate that the neural mechanism for motion coherence is sensitive to the phase relationship between chromatic and luminance contrast, a finding which has implications for interactions between 'color' and 'motion' processing streams in the primate visual system.

Nahm, F.K., Perret, A., Amaral, D.G., Albright, T.D. How do monkeys look at faces? (1997) Journal of Cognitive Neuroscience. 9(5):611-23. DOI: 10.1162/jocn.1997.9.5.611

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Chaudhuri, A., Albright, T.D. Neuronal responses to edges defined by luminance vs. temporal texture in macaque area V1. (1997) Visual Neuroscience. 14(5):949-62.

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Croner, L.J., Albright, T.D. Image segmentation enhances discrimination of motion in visual noise. (1997) Vision Research. 37(11):1415-27.

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Albright, T.D. An excellent lightness. (1996) Science. 273(5278):1055-6.

Stoner, G.R., Albright, T.D. The interpretation of visual motion: evidence for surface segmentation mechanisms. (1996) Vision Research. 36(9):1291-310.

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The independent motions of objects in a visual scene are commonly manifest as overlapping retinal motions. A consequence of this overlap is the creation of spurious retinal image features--such as corners and terminated contours--that bear no direct relation to the motions of the objects that give rise to them. To reconstruct object motions, these emergent features must be distinguished from the retinal motions of real object features. This process can be studied using visual stimuli known as plaid patterns, which provide a laboratory archetype for the ubiquitous real-world circumstance of two surfaces with overlapping retinal projections. By adjusting luminance relationships in a plaid pattern it is possible to influence the perceptual interpretation of image features, such that they are seen as either an emergent consequence of occlusion or as real variations in surface reflectance. In the former case, the plaid is most likely to be to perceived as two independently moving surfaces, whereas the latter generally elicits a percept of a single moving surface. This dependence of motion perception on luminance configuration can be viewed as evidence for the involvement of surface segmentation mechanisms, which distinguish between real and emergent image features by promoting a depth-ordered neural representation of surfaces. An alternative interpretation, which does not demand such depth-ordering and feature classification, asserts that the effect of luminance configuration can be accounted for by attendant variations in the distribution of moving Fourier components. To evaluate these two proposed mechanisms, we designed novel plaid stimuli in which surface segmentation cues could be varied independently of changes in the distribution of Fourier components. Perceived motion was found to be highly correlated with the presence of appropriate segmentation cues and uncorrelated with the distribution of Fourier components. These results refute the Fourier components hypothesis, and they support our proposal that surface segmentation plays a critical role in the interpretation of visual motion signals.

Buracas, G.T., Albright, T.D. Contribution of area MT to perception of three-dimensional shape: a computational study. (1996) Vision Research. 36(6):869-87.

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Albright, T.D. 'My most true mind thus makes mine eye untrue'. (1995) Trends in Neurosciences. 18(8):331-3.

Albright, T.D., Stoner, G.R. Visual motion perception. (1995) Proceedings of the National Academy of Sciences of the United States of America. 92(7):2433-40.

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Dobkins, K.R., Albright, T.D. Behavioral and neural effects of chromatic isoluminance in the primate visual motion system. (1995) Visual Neuroscience. 12(2):321-32.

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Scalaidhe, S.P., Albright, T.D., Rodman, H.R., Gross, C.G. Effects of superior temporal polysensory area lesions on eye movements in the macaque monkey. (1995) Journal of Neurophysiology. 73(1):1-19.

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1. On the basis of its anatomic connections and single-unit properties, the superior temporal polysensory area (STP) would seem to be primarily involved in visuospatial functions. We have examined the effects of lesions of STP on saccadic eye movements, visual fixation, and smooth pursuit eye movements to directly test the hypothesis that STP is involved in visuospatial and visuomotor behavior. 2. Seven monkeys were trained to make saccades to targets 8, 15, and 22 degrees from a central fixation point along the horizontal meridian and 8 degrees from the central fixation point along the vertical meridian. One monkey was also trained to make saccades to auditory targets. The same monkeys were trained to foveate a stationary central fixation point and to follow it with a smooth pursuit eye movement when it began moving 5, 13, or 20 degrees/s. Four monkeys received unilateral STP lesions, one received a bilateral STP lesion, and as a control, two received unilateral inferior temporal cortex (IT) lesions. After testing, three of the animals with unilateral STP lesions received an additional STP lesion in the hemisphere contralateral to the first lesion. Similarly, one animal with a unilateral IT lesion received an additional IT lesion in the hemisphere contralateral to the first lesion. 3. All monkeys with complete removal of STP showed a significant increase in saccade latency to the most peripheral contralateral target, and most also had increased saccade latencies to the other contralateral targets. Saccades directed to targets along the vertical meridian or toward targets in the hemifield ipsilateral to the lesion were not impaired by removal of STP. By contrast, IT lesions did not impair the monkeys' ability to make saccadic eye movements to visual stimuli at any location, showing that saccades to visually guided targets are not impaired nonspecifically by damage to visual cortex. 4. The deficit in making eye movements after STP lesions was specific to saccade latency, with little effect on the accuracy of saccades to visual targets. 5. In the one monkey trained to make saccades to auditory targets, removal of STP did not impair saccades to auditory targets contralateral to its lesion, despite this monkey showing the largest increase in saccades latencies to visual targets. 6. There was complete recovery of saccade latency to the baseline level of performance on the saccade task after all STP lesions.(ABSTRACT TRUNCATED AT 400 WORDS)

Dobkins, K.R., Albright, T.D. What happens if it changes color when it moves?: the nature of chromatic input to macaque visual area MT. (1994) Journal of Neuroscience. 14(8):4854-70.

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Neurons in the middle temporal visual area (MT) of macaque cerebral cortex are highly selective for the direction of motion but not the color of a moving stimulus. Recent experiments have shown, however, that the directional selectivity of many MT neurons persists even when a moving stimulus is defined solely by chromatic variation (Charles and Logothetis, 1989; Saito et al., 1989; Dobkins and Albright, 1991 a, b; Movshon et al., 1991; Gegenfurtner et al., 1994). To illuminate the mechanisms by which area MT uses color as a cue for motion correspondence, we recorded from MT neurons while rhesus monkeys viewed an "apparent motion" stimulus in which red/green sine wave gratings underwent contrast reversal each time they were displaced in a particular direction. Under such conditions, correspondence based upon chromatically defined borders conflicts with correspondence based upon conservation of chromatic sign. When our heterochromatic stimuli possessed sufficient luminance modulation, MT neurons responded best to motion in the direction for which the sign of luminance (and chromatic) contrast was preserved. At isoluminance, however, two different chromatic influences were revealed. First, when stimuli underwent small spatial displacements, directional selectivity was elicited by movement of the stimulus in the direction of the nearest chromatically defined border, even though the sign of chromatic contrast at that border alternated over time. Under these conditions, MT neurons apparently exploited information about image borders defined by chromatic contrast while sacrificing information about the colors that make up those borders. By contrast, when chromatically defined borders provided only ambiguous information about direction of motion, MT neurons were capable of using information about the sign of chromatic contrast to detect direction of motion. The results from these experiments suggest the existence of a hybrid mechanism, one in which both signed and unsigned chromatic signals contribute to motion processing in visual area MT.

Albright, T.D. Why do things look as they do? (1994) Trends in Neurosciences. 17(5):175-7.

Nahm, F.K., Dale, A.M., Albright, T.D., Amaral, D.G. In vivo microelectrode localization in the brain of the alert monkey: a combined radiographic and magnetic resonance imaging approach. (1994) Exp Brain Res. 98(3):401-11.

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Dobkins, K.R., Albright, T.D. What happens if it changes color when it moves?: psychophysical experiments on the nature of chromatic input to motion detectors. (1993) Vision Research. 33(8):1019-36.

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Stoner, G.R., Albright, T.D. Image segmentation cues in motion processing: implications for modularity in vision. (1993) Journal of Cognitive Neuroscience. 5(2):129-49. DOI: 10.1162/jocn.1993.5.2.129

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Albright, T.D. Cortical processing of visual motion. (1993) Rev Oculomot Res. 5:177-201.

Chaudhuri, A., Albright, T.D. Heterochromatic Fusion Nystagmus: its use in estimating chromatic equiluminance in humans and monkeys. (1992) Vision Research. 32(9):1745-59.

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Stoner, G.R., Albright, T.D. Neural correlates of perceptual motion coherence. (1992) Nature. 358(6385):412-4. DOI: 10.1038/358412a0

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Stoner, G.R., Albright, T.D. Motion coherency rules are form-cue invariant. (1992) Vision Research. 32(3):465-75.

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Albright, T.D. Form-cue invariant motion processing in primate visual cortex. (1992) Science. 255(5048):1141-3.

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Albright, T.D. Motion perception and the mind-body problem. (1991) Current Biology. 1(6):391-3.

Albright, T.D. Color and the integration of motion signals. (1991) Trends in Neurosciences. 14(7):266-9.

Chaudhuri, A., Albright, T.D. A new technique for estimating chromatic isoluminance in humans and monkeys. (1990) Visual Neuroscience. 5(6):605-8.

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Rodman, H.R., Gross, C.G., Albright, T.D. Afferent basis of visual response properties in area MT of the macaque. II. Effects of superior colliculus removal. (1990) Journal of Neuroscience. 10(4):1154-64.

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Stoner, G.R., Albright, T.D., Ramachandran, V.S. Transparency and coherence in human motion perception. (1990) Nature. 344(6262):153-5. DOI: 10.1038/344153a0

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Rodman, H.R., Gross, C.G., Albright, T.D. Afferent basis of visual response properties in area MT of the macaque. I. Effects of striate cortex removal. (1989) Journal of Neuroscience. 9(6):2033-50.

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Rodman, H.R., Albright, T.D. Single-unit analysis of pattern-motion selective properties in the middle temporal visual area (MT). (1989) Exp Brain Res. 75(1):53-64.

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Albright, T.D. Centrifugal directional bias in the middle temporal visual area (MT) of the macaque. (1989) Visual Neuroscience. 2(2):177-88.

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Albright, T.D., Desimone, R. Local precision of visuotopic organization in the middle temporal area (MT) of the macaque. (1987) Exp Brain Res. 65(3):582-92.

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Rodman, H.R., Albright, T.D. Coding of visual stimulus velocity in area MT of the macaque. (1987) Vision Research. 27(12):2035-48.

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Schwartz, E.L., Desimone, R., Albright, T.D., Gross, C.G. Shape recognition and inferior temporal neurons. (1983) Proceedings of the National Academy of Sciences of the United States of America. 80(18):5776-8.

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Thomas Albright

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