Object Perception
object perception
Jorge Almeida
I am looking for a Post-Doctoral Researcher. The applicants should have obtained a PhD, and have an overall interest in object recognition, potentially focusing on object-related features like shape, texture material and surface properties. I am particularly interested in researchers with strong expertise in fMRI, and in particular decoding and multivariate approaches. Good programming skills, great communication and mentoring skills, and a great command of English are a plus. The selected applicant will work with me (Jorge Almeida) but will also benefit from the lively academic environment and research groups we are currently building in the Psychology Department of the University of Coimbra, Portugal (Jason Fischer, Joana Carvalho, Alfonso Caramazza, etc). The projects will relate to my work on object and mid-level processing. Below are some examples: Mahon, B. Z., & Almeida, J. (2024). Reciprocal interactions among parietal and occipito-temporal representations support everyday object-directed actions. Neuropsychologia, 198, 108841. https://doi.org/10.1016/j.neuropsychologia.2024.108841 Almeida, J., Fracasso, A., Kristensen, S., Valério, D., Bergström, F., Chakravarthi, R., Tal, Z., & Walbrin, J. (2023). Neural and behavioral signatures of the multidimensionality of manipulable object processing. Communications biology, 6(1), 940. https://doi.org/10.1038/s42003-023-05323-x Walbrin, J., & Almeida, J. (2021). High-Level Representations in Human Occipito-Temporal Cortex Are Indexed by Distal Connectivity. The Journal of neuroscience : the official journal of the Society for Neuroscience, 41(21), 4678–4685. https://doi.org/10.1523/JNEUROSCI.2857-20.2021 The position is for 2 to 3 years, and the salary is the standard Post-Doctoral pay-scale in Portugal (net value 1850 euros per month; this is a competitive salary for the cost of living in Portugal and especially in Coimbra). Start time should be as soon as possible. The Proaction Lab is currently well-funded as we have a set of on-going funded projects including a Starting Grant ERC to Jorge Almeida, a major European ERA Chair project to Jorge Almeida and Alfonso Caramazza, and other projects. We have access to a 3T MRI scanner with a 32-channel coil, to a 7T scanner (in collaboration with a site outside of Portugal), to tDCS, and to a fully set psychophysics lab. We have a 256 ch EEG, motion tracking and eyetracking on site. We also have a science communication office dedicated to the lab. Finally, the University of Coimbra is a 700-year-old University and has been selected as a UNESCO world Heritage site. Coimbra is one of the liveliest university cities in the world, and it is a beautiful city with easy access to the beach and mountain. You should apply as soon as you can. If interested send an email to jorgecbalmeida@gmail.com, with a CV, and motivation/scientific proposal letter.
Jorge Almeida
I am looking for a Post-Doctoral Researcher at the initial stages (defending very soon, and no more than 2 years and half after obtaining their PhD). The applicants should have obtained a PhD, and have an overall interest in object recognition, potentially focusing on object-related features like shape, texture material and surface properties. I am particularly interested in researchers with strong expertise in fMRI, and in particular decoding and multivariate approaches. Good programming skills, great communication and mentoring skills, and a great command of English are a plus. The selected applicant will work with me (Jorge Almeida) but will also benefit from the lively academic environment and research groups we are currently building in the Psychology Department of the University of Coimbra, Portugal (Jason Fischer, Joana Carvalho, Alfonso Caramazza, etc). The projects will relate to my work on object and mid-level processing. Below are some examples: Mahon, B. Z., & Almeida, J. (2024). Reciprocal interactions among parietal and occipito-temporal representations support everyday object-directed actions. Neuropsychologia, 198, 108841. https://doi.org/10.1016/j.neuropsychologia.2024.108841 Almeida, J., Fracasso, A., Kristensen, S., Valério, D., Bergström, F., Chakravarthi, R., Tal, Z., & Walbrin, J. (2023). Neural and behavioral signatures of the multidimensionality of manipulable object processing. Communications biology, 6(1), 940. https://doi.org/10.1038/s42003-023-05323-x Walbrin, J., & Almeida, J. (2021). High-Level Representations in Human Occipito-Temporal Cortex Are Indexed by Distal Connectivity. The Journal of neuroscience : the official journal of the Society for Neuroscience, 41(21), 4678–4685. https://doi.org/10.1523/JNEUROSCI.2857-20.2021 The position is for 2 to 3 years, and the salary is the standard Post-Doctoral pay-scale in Portugal (net value 1850 euros per month; this is a competitive salary for the cost of living in Portugal and especially in Coimbra). Start time should be as soon as possible. The Proaction Lab is currently well-funded as we have a set of on-going funded projects including a Starting Grant ERC to Jorge Almeida, a major European ERA Chair project to Jorge Almeida and Alfonso Caramazza, and other projects. We have access to a 3T MRI scanner with a 32-channel coil, to a 7T scanner (in collaboration with a site outside of Portugal), to tDCS, and to a fully set psychophysics lab. We have a 256 ch EEG, motion tracking and eyetracking on site. We also have a science communication office dedicated to the lab. Finally, the University of Coimbra is a 700-year-old University and has been selected as a UNESCO world Heritage site. Coimbra is one of the liveliest university cities in the world, and it is a beautiful city with easy access to the beach and mountain. You should apply as soon as you can. If interested send an email to jorgecbalmeida@gmail.com, with a CV, and motivation/scientific proposal letter.
The contribution of the dorsal visual pathway to perception and action
The human visual system enables us to recognize objects (e.g., this is a cup) and act upon them (e.g., grasp the cup) with astonishing ease and accuracy. For decades, it was widely accepted that these different functions rely on two separated cortical pathways. The ventral occipitotemporal pathway subserves object recognition, while the dorsal occipitoparietal pathway promotes visually guided actions. In my talk, I will discuss recent evidence from a series of neuropsychological, developmental and neuroimaging studies that were aimed to explore the nature of object representations in the dorsal pathway. The results from these studies highlight the plausible role of the dorsal pathway in object perception and reveal an interplay between shape representations derived by the two pathways. Together, these findings challenge the binary distinction between the two pathways and are consistent with the view that object recognition is not the sole product of ventral pathway computations, but instead relies on a distributed network of regions.
A computational explanation for domain specificity in the human brain
Many regions of the human brain conduct highly specific functions, such as recognizing faces, understanding language, and thinking about other people’s thoughts. Why might this domain specific organization be a good design strategy for brains, and what is the origin of domain specificity in the first place? In this talk, I will present recent work testing whether the segregation of face and object perception in human brains emerges naturally from an optimization for both tasks. We trained artificial neural networks on face and object recognition, and found that networks were able to perform both tasks well by spontaneously segregating them into distinct pathways. Critically, networks neither had prior knowledge nor any inductive bias about the tasks. Furthermore, networks optimized on tasks which apparently do not develop specialization in the human brain, such as food or cars, and object categorization showed less task segregation. These results suggest that functional segregation can spontaneously emerge without a task-specific bias, and that the domain-specific organization of the cortex may reflect a computational optimization for the real-world tasks humans solve.
Human reconstruction of local image structure from natural scenes
Retinal projections often poorly represent the structure of the physical world: well-defined boundaries within the eye may correspond to irrelevant features of the physical world, while critical features of the physical world may be nearly invisible at the retinal projection. Visual cortex is equipped with specialized mechanisms for sorting these two types of features according to their utility in interpreting the scene, however we know little or nothing about their perceptual computations. I will present novel paradigms for the characterization of these processes in human vision, alongside examples of how the associated empirical results can be combined with targeted models to shape our understanding of the underlying perceptual mechanisms. Although the emerging view is far from complete, it challenges compartmentalized notions of bottom-up/top-down object segmentation, and suggests instead that these two modes are best viewed as an integrated perceptual mechanism.