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Biography

Diego Mendoza-Halliday is an Assistant Professor in the Department of Neuroscience at the University of Pittsburgh and Principal Investigator of the Mendoza-Halliday Lab. He is also Training Faculty in the Neuroscience Institute Graduate Programs at Â鶹´å, a Faculty member at the Center for the Neural Basis of Cognition, and a Research Affiliate in the McGovern Institute for Brain Research at MIT. Previously, he worked as a Postdoctoral Fellow and Research Scientist in the lab of Dr. Robert Desimone at MIT, where he applied multi-electrode laminar recordings and developed optogenetic tools to investigate the neuronal mechanisms of visual feature attention, working memory, and their interaction. Dr. Mendoza-Halliday completed his PhD in Cognitive Neurophysiology at McGill University under the research mentorship of Dr. Julio Martinez-Trujillo.

Education

• Ph.D. McGill University (2014)
• Postdoc / Research Scientist, Massachusetts Institute of Technology

Research

Our brain has the extraordinary ability to actively maintain and manipulate mental representations in working memory—even without the use of our senses. Representations in working memory can be manipulated by transforming them (e.g., mental math) or monitoring them (e.g., mentally going over a to-do list), among others. Our ability to manipulate representations—not to simply maintain or store them—is what makes working memory fundamental for other cognitive abilities such as attention, problem-solving, decision-making and action-planning, and is the core of human intelligence, imagination, and creativity.

​One of the central research aims of the Mendoza-Halliday Lab is to understand the mechanisms underlying the manipulation (transformation and monitoring) of working memory representations at the level of single neurons, microcircuits, and neuronal populations across multiple brain regions. We also aim to understand the relationship between the mechanisms of working memory maintenance and manipulation, as well as how these mechanisms support other brain functions such as perception, attention, and others.

To examine these mechanisms, we simultaneously monitor the activity of large numbers of individual neurons across cortical layers and across multiple brain regions using high-density laminar electrophysiological methods in animal models during the performance of complex visual cognitive tasks requiring the maintenance and manipulation (transformation or monitoring) of mental representations in working memory. This allows us to investigate how electrophysiological activity in different neurons, neuron types, cortical layers, and brain regions, as well as their communication, relates to these cognitive functions. To examine the causal role that neurons in different brain regions play in working memory maintenance and manipulation, we experimentally inactivate or activate these neurons using customized large-scale optogenetic methods we developed.

Publications

Mendoza-Halliday, D., Xu, H., Azevedo, F.A.C., Desimone, R. (2024) Dissociable neuronal substrates of feature attention and working memory. Neuron 112 (5), 850-863.

Mendoza-Halliday, D.*, Major, A.J.*, Lee, N., Lichtenfeld, M., Carlson, B., Mitchell, B., Meng, P.D. Xiong, Y., Westerberg, J., Jia, X., Johnston, K.D., Selvanayagam, J., Everling, S., Maier, A., Desimone, R.**, Miller, E.K.**, Bastos, A.M.**. (2024) A ubiquitous spectrolaminar motif of local field potential power across the primate cortex. Nature Neuroscience 27, 547–560.

Gong, X.*, Mendoza-Halliday, D.*, Ting, J.T.*, Kaiser, T., Sun, X., Bastos, A.M., Wimmer, R.D., Guo, B., Chen, Q., Zhou, Y., Pruner, M., Wu, C., Park, D., Deisseroth, K., Barak, B., Boyden, E.S., Miller, E.K., Halassa, M.M., Fu, Z., Bi, G., Desimone, R., Feng, G. (2020). An ultra-sensitive step-function opsin for minimally invasive optogenetic stimulation in mice and macaques. Neuron 107 (1), 38-51.

Mendoza-Halliday, D., Martinez-Trujillo, J.C. (2017). Neuronal population coding of perceived and memorized visual features in the lateral prefrontal cortex. Nature Communications 8, 15471.

Mendoza-Halliday, D., Torres, S., Martinez-Trujillo, J.C. (2014). Sharp emergence of feature-selective sustained activity along the dorsal visual pathway. Nature Neuroscience 17 (9), 1255.

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