Dr Tom Freeman - BSc PhD Birm
Research Summary
Images move mainly because we do. Simple actions like tracking a moving target by eye, make stationary objects sweep across the retina. More complex actions, like walking and driving, cause the visual scene to smoothly expand in the image. Our own movements therefore create some very basic problems for the brain – how does the visual system know whether we are moving, objects are moving, or both? One solution the brain adopts is to use signals from the motor system to help interpret incoming visual information as we move.
My work investigates the fundamental mechanisms that drive this process, using a variety of techniques. These include measuring how well we can control our eye movements, how successful we are at judging object motion and which regions of the brain are active as we do so.
Teaching Summary
Levels 1 and 2:
I give a variety of tutorials as Levels 1 and 2 on perception, cognition, developmental and abnormal psychology (supporting PS1014, PS2003, PS2008, PS2009). At Level 2, I teach one half of the Perception module (PS2009), concentrating on ‘The Other senses’. I also run practicals in Perception.
Level 3:
I teach and coordinate the ‘Vision and Action’ module, where we examine our current understanding of visual perception during motor activity and how visual perception helps support action. I supervise projects on a number of topics in perception.
Selected Publications (2008 onwards)
Champion, R.A., & Freeman, T.C.A. (2010). Discrimination contours for the perception of head-centred velocity. Journal of Vision, 10(6):14, 1–9. [pdf]
Freeman, T.C.A., Champion, R.A., & Warren, P.A. (2010). A Bayesian model of perceived head-centred velocity during smooth pursuit eye movement. Current Biology, 20, 757-762. [pdf]
Kolarik, A.J., Margrain, T.H., & Freeman, T.C.A. (2010). Precision and accuracy of ocular following: Influence of age and type of eye movement. Experimental Brain Research. 201, 271-282. [pdf]
Edden, R.A.E., Muthukumaraswamy, S.D., Freeman, T.C.A., & Singh, K.D. (2009). Orientation discrimination performance is predicted by GABA concentration and gamma oscillation frequency in human primary visual cortex. Journal of Neuroscience, 29, 15721-15726. [pdf]
Freeman, T. C. A., Champion, R. A., Sumnall, J. H., & Snowden, R. J. (2009). Do we have direct access to retinal image motion during smooth pursuit eye movements? Journal of Vision, 9(1):33, 1-11. [pdf]
Souman, J.L., & Freeman, T.C.A. (2008). Motion perception during sinusoidal smooth pursuit eye movements: Signal latencies and non-linearities. Journal of Vision, 8, 14, 1-14. [pdf]