Professor Andrew T Smith

Personal profile

 

I am an emeritus professor in neuroscience with interests in sensory processing.

Most of my early career was devoted to visual psychophysics. My main contribution during that period concerned the mechanisms employed by the human brain for detecting motion within the retinal image. Two themes emerge from this work. The first concerns speed of motion, which was largely neglected in early (1980s) computational models of motion detection that focused on direction of motion. My work on speed perception culminated in an influential model of the extraction of speed using two temporal channels (1994). The second theme concerns second-order motion. This refers to motion defined not in terms of luminance but in terms of attributes derived from luminance, such as contrast and texture. My work contributed strongly to a now-large body of evidence for separate detection mechanisms for first-order and second-order motion.

In later years, I switched my attention to fMRI research. I was among the first (in 1997) to embrace this new methodology, against the judgement of many colleagues in the visual psychophysics community. In 2003 a 3T scanner was installed at Royal Holloway under my instigation and management. My own MRI work encompassed a range of projects. With colleagues, I discovered two previously unknown visual areas of the brain that are now widely known in the field: V3B (J Neurosci 1998) and CSv (Current Biology 2008). Over time, my main interest became how self-motion is encoded and monitored. I used fMRI to study the responses of motion-sensitive areas of the brain to the “optic flow” that arises on the retina when we move around. I identified several visual cortical areas which (unlike the best-known motion areas, MT and MST) respond to retinal motion only if it reflects self-motion (as opposed to object motion). I also explored the vestibular inputs to these ‘visual’ areas by delivering artificial (galvanic) vestibular stimulation in the scanner.

In addition to extensive fMRI work on motion, I have published highly cited papers on several sidelines, in particular demonstrating with fMRI that spatial attention suppresses activity in non-attended locations and identifying brain regions that mediate time perception. I have also contributed to fMRI methodology, in particular developing a method for estimating receptive field sizes in human visual cortex (Cerebral Cortex 2001) that provided the foundation for others to develop the now-widespread technique of population receptive field (pRF) measurement.

I retain my interest in sensory processing but I no longer have a lab at Royal Holloway.

 

Publications: listed in order of impact (Google Scholar) or date order.

 

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