Positions

Research over the past decades has clarified how early representations of visual inputs in retinotopic visual areas are transformed to compact, high-level visual object codes in inferotemporal (IT) cortex. But how these high-level visual object codes are transformed into even higher-level semantic codesthat can directly guide internal action goals remains unclear. We propose to tackle the problem of semantic visual coding through experiments leveraging the macaque face patch system. Two key questions are: 1) What is the high-level semantic code for objects in the brain?  2) How can high-level semantic representations re-activate/modulate sensory representations? Functional magnetic resonanceimaging (fMRI) studies have shown that visual imagery activates a network of frontal parietal regions as well asvisual areas selective to faces and scenes during passive viewing. But fMRI gives only a blurry picture. We propose to use fMRI-guided electrophysiology to investigate the detailed neural dynamics underlying semantic representation across prefrontal cortex, the medial temporal lobe, and inferotemporal cortex. Our ability to target face patches gives us huge leverage to dissect how high-level sensory cortex responds to internally driven, “offline” activation of sensory representations. Successful applicants should have experience with imaging, electrophysiology, and computational analysis, and a deep interest in the neural underpinnings of semantic representation.  For more information please contact Doris.

The O’Doherty and Tsao labs at the California Institute of Technology in collaboration with Dr. Daeyeol Lee at Yale University are seeking candidates for two postdoctoral positions in neuroscience. Successful applicants will be part of a collaborative project supported by the BRAIN initiative aimed at elucidating the relationship between neuronal activity and hemodynamic responses in the prefrontal cortex, particularly regarding the representation of value, decision and reward signals. The project will involve acquiring single and multi-unit electrophysiological data as well as implementing fMRI experiments in non-human primates and ultimately in human patients. Preference will be given to candidates with prior experience in the electrophysiological recording of neuronal activity. A prior background in the training and implementation of cognitive tasks in non-human primates would be desirable. Experience with and knowledge of computational models of reinforcement-learning and other models of decision-making would be useful and prior experience of fMRI experiments and data analysis would be an advantage.  For more information please contact John O’Doherty jdoherty@caltech.edu, and/or Doris Tsao, doristsao@caltech.edu . To apply please send a cover letter, curriculum vitae and the names of 3 referees to Ms. Mary Martin: mmartin@caltech.edu.

A postdoctoral position is available to study mechanisms for visual object segmentation in the awake rodent in the Tsao lab at Caltech.  How does the brain dynamically link all the pixels belonging to a persistent visual object over space and time? We hypothesize that this is a fundamental function of rodent vision, and we want to apply the full arsenal of rodent neural circuit dissection tools including two-photon imaging and electrophysiology to understand the underlying mechanisms. Candidates should have a PhD in Neuroscience or related discipline, be highly motivated, have strong quantitative skills, and work well with others. Experience with two photon imaging and/or electrophysiology in rodents is especially welcome.  The project is funded by a five year NIH Pioneer Grant.  Applicants should send a letter of interest and CV to Doris.