While most visual input produces normal stable vision, when visual information is ambiguous our brain does something uncharacteristic, it wavers. When visual information is ambiguous awareness tends to waver continuously between alternative interpretations.
Ambiguous vision has received tremendous interest from a broad array of researchers. This is, in part, because it allows investigators to dissociate low-level physical stimulation from fluctuations in perceptual awareness, providing a valuable tool for investigating the neural basis of visual awareness. Research ideas using instances of ambiguous vision to investigate aspects of perceptual awareness would be welcome.
Mental imagery is ubiquitous in daily life, and can be experienced in a variety of situations, such as when imagining the smile of close friend, the colours in a favourite painting or a possible shortcut to a destination. Recently we discovered that binocular rivalry (a type of ambiguous vision) could be employed as an effective tool to measure a single instance of imagery (Pearson, Clifford & Tong, 2008). This exciting discovery allowed us to show that visual imagery is much like a weak version of normal vision, displaying many the characteristics of low-level visual perception. Despite imagery’s importance to most sensory and cognitive processes it remains poorly understood. The lab is in the process of using this newly discovered investigative tool to shed light on many of the mysteries surrounding mental imagery.
Despite the immense processing power of the human brain, there are severe limitations to what we can remember about a single conscious moment. The amount and type of information held in visual memory is poorly understood. The lab is currently investigating the dynamics of visual memory employing behavioural, neural imaging and neural disruption techniques. The findings will reveal whether different memory processes rely on common or independent traces in the visual system, identify the neural substrates of these memory traces and redefine the major categories of visual short-term memory. The results will have significant implications for models of human memory, cognitive performance, visual consciousness and clinical diagnosis of memory impairments.
The three experimental methods the lab utilises are behavioural psychophysics, functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS), all with human subjects.
What is TMS?
Transcranial magnetic stimulation (TMS) is a technique that offers the unique possibility to undertake non-invasive cause-effect research into the neural basis of human cognition and perception. TMS is a valuable neuroscience research method that rapidly gaining popularity in research laboratories around the world.