Research

Research in our laboratory focuses on the neural structures and events underlying the perception of motion, form, and color. Recent studies of the primate cerebral cortex have unveiled the existence of multiple areas devoted to the processing of visual information. Richly interconnected collections of these areas constitute functional subsystems for the detection, analysis, and interpretation of specific types of visual information. Through an integrative approach, which combines neurophysiological and psychophysical techniques, as well as computational modeling of neural networks, we are beginning to illuminate the mechanics of information processing in these high-level visual areas and to define their unique contributions to visual perception and visually guided behavior.

"Light reflected from objects in the environment projects onto the retinal surface, resulting in intricate and dynamic patterns of brightness and color. Human observers interpret these images, nearly instantaneously and generally without awareness, to yield unequivocal and behaviorally informative percepts. Our goal has been to understand the neuronal structures and events that underlie visual perceptual experience and its contributions to knowledge, behavior and consciousness."

We live in a dynamic environment. Optimal encoding of sensory information requires that sensory systems be continuously tuned to the prevailing environment, much like finetuning your car for the current driving conditions. Yet while it is important that sensory information be represented with high fidelity, the brain has only limited resources available. Albright and his team are interested in how neural systems reconcile these conflicting demands in the visual system.

Using their working hypothesis that sensory systems resolve the dilemma by way of compromise, the scientists examined the effects of sensory resource reallocation—a phenomenon commonly known as sensory adaptation—on the perception of visual motion. The initial theoretical work led to predictions about the patterns of perceptual and neuronal change expected in a system that reallocates its resources to dynamically optimize perception in a changing environment. Behavioral studies put these predictions to the test by revealing the perceptual changes induced by adaptation. Physiological studies uncover the neuronal mechanisms of sensory reallocation.

The results reveal that sensory systems enhance the neuronal representation of those aspects of the environment that are frequently encountered and are significant for successful behavior. The enhancement comes at the cost of reduced sensitivity to those stimuli that are less commonly encountered. Specifically, the observed perceptual recalibration is mediated by changes in motion-selective neurons in the visual cortex. Some of the neurons change their sensitivity to particular stimuli and others shift their sensitivity to other stimuli. These findings indicate that the neuronal mechanisms of perception can only be understood by studying how sensitivity is dynamically distributed across neurons tuned to the entire range of visible stimuli.

Taken together, the observations of Albright and his colleagues reveal that sensory processing is markedly adaptable. This adaptability enables us to optimize perception and behavior in a world that presents us with varying sensory demands, caused by changes in the environment, behavioral goals and age-related decline in sensory function.

Back row, left to right: Lee Campbell, Varun Chaturvedi, Ben Berthet, Octavio Ruiz, Thomas Albright, Marco Lopes, Christian Wehrhahn

Front row, left to right: Ricardo Gil da Costa, Ambarish Pawar, Sunwoo Kwon, Sergei Gepshtein, Dinh Diep, Raynard Fung, Gene Stoner, Maria Pacheco, Chris Hiestand, Hulusi Kafaligonul and his daughter

Selected Publications

Wachtler T, Sejnowski TJ and Albright TD (2003) Representation of color stimuli in awake macaque primary visual cortex. Neuron, 37, 681-691.

Krekelberg B and Albright TD (2005) Motion mechanisms in macaque MT, J. Neurophysiol., 93, 2908-2921.

Messinger A, Squire LR, Zola SM, and Albright TD (2005) Neural correlates of knowledge: Stable representation of stimulus associations across variations in behavioral performance. Neuron, 48, 359-371.

Krekelberg B, Van Wezel RJ, Albright TD (2006) Interactions between speed and contrast tuning in Middle Temporal Area: Implications for the neural code for speed. J. Neurosci., 26, 8988-8998.

Huang X, Albright TD, and Stoner GR. (2007) Adaptive surround modulation in cortical area MT. Neuron. 53:761-770.

Schlack A, and Albright TD. (2007) Remembering Visual Motion: Neural Correlates of Associative Plasticity and Motion Recall in Cortical Area MT. Neuron. 53:881-890.

Schlack A, Krekelberg B, and Albright TD. (2007). Recent history of stimulus speeds affects the speed tuning of neurons in area MT. J. Neurosci., 27, 11009-11018.

Salk News Releases

• Despite what you may think, your brain is a mathematical genius
  April 10, 2013
• Thomas D. Albright named president of Academy of Neuroscience for Architecture
  November 14, 2012
• Salk Announces $2 Million Gift from Mr. Conrad T. Prebys for an Endowed Chair in Vision Research
  February 15, 2011
• NIH designates Salk Institute one of seven national basic research centers focused on vision
  July 13, 2009
• Salk scientist Thomas Albright elected to National Academy of Sciences
  April 30, 2008
• Associative memory: Learning at all levels
  March 15, 2007
• Neurons that detect motion rapidly switch between modes of data collection
  February 28, 2007
• Your brain cells may 'know' more than you let on by your behavior
  October 19, 2005
• Salk Professor Thomas Albright Elected to American Academy of Arts and Sciences
  May 9, 2003

Awards and Honors

• McKnight Neuroscience Development Award 1991
• Sloan Foundation Research Fellowship 1989
• Howard Hughes Medical Institute Investigator, 1997
• National Academy of Sciences Award for Initiatives in Research, 1995
• American Academy of Arts and Sciences 2003
• National Academy of Sciences, 2008

Links

Albright lab