Sensory processing is ubiquitous in our interactions with the environment, is performed with extreme efficiency, and forms the basis for many of our routine daily decisions. A pervasive idea in cognitive science is that perceptual decisions (such as object categorization) are the result of a comparison of sensory evidence that is accumulated over time. Findings from both neurophysiology and neuroimaging now suggest that the brain solves the problem of perceptual decision-making using an accumulator architecture that is conceptually similar to these models. Using the accumulator model as a framework, the PANLab seeks to understand how the brain processes sensory evidence, how that sensory evidence interacts with previous experiences, how that interaction contributes to decision making, and how those decisions lead to environmentally-appropriate actions. The research program emphasizes the understanding of fudamental cognitive operations, which can then be applied to populations with atypical or impaired cognitive function. Research involves a combination of experimental techniques, including functional MRI, psychophysics, TMS, and EEG.
With some notable exceptions, most perception researchers, either explicitly or implicitly, consider the perception of objects to be one particular end-goal of cognitive systems. One's detailed perceptual experience of the environment is very convincing with regard to the idea that the primary job of perceptual systems must be to produce that rich phenomenonological experience. However, this is not the approach taken in the PANLab. For human perceptual systems to have evolved their particular characteristics, their end-goal must be to act on the environment. Thus, the primary purpose of perceptual systems is to filter sensory information in a way that leads to the selection of adaptive environmentally-appropriate actions. Taking this idea a step further, it is possible to conceive of the brain as consisting of only sensory and motor systems (also see work by Joaquin Fuster, UCLA). Sensory systems filter input and motor systems produce actions; long-lived concepts such as association cortex, perception, memory, and executive function are merely more abstract cases of the same neural functions that can be found in traditional sensorimotor cortex. In my view, these "functions" can be quantified as mathematical transformations. Primary sensorimotor cortices apply transformations that can be easily compared to concrete parameters of the external environment and are therefore judged as more concrete or "primary". Other cortical areas are further removed from the periphery along the signal chain (a loose hierarchy) and the transformations they apply are not as easily relatable to parameters of the external environment. In this way, traditional association cortices can be considered functionally more abstract than primary sensorimotor cortices.
Jerry S. Fisher (undergraduate RA) 2009
Psychology by definition is "the science that deals with mental processes and behavior" (American Heritage Dictionary). As a cognitive neuroimaging lab, we hope to contribute to this discipline through a greater understanding of the neural substrates that support our mind and mental processes. The human brain is perhaps one of the most fascinating all of evolution's orchestrations. Through its complex bundles of neurons, fibers, and structures, rests the mysterious underpinnings for all of our thoughts, emotions, and memories. It would be no great stretch to say the brain is the house of our selves. And yet for all this, we know so little about it. What is the true relationship between our minds and the world around us? In what ways do we come to know and recognize the outside world? How is this knowledge shaped and integrated by our biological framework? How is it preserved? Endless questions exist and as of now we have breached only the top tip of the ice burg. Our motivation in this lab is to scratch the surface a little further. With the advent of noninvasive functional magnetic resonance imaging, this unseen realm of the human brain in action can be explored a little further. It is a fascinating venture, and we are proud to be a part of it.