Theoretical and Applied Studies of Conscious Perception: Neuroimaging Investigations using the Fringe-P3 Brain-Computer Interface

Secondary Supervisor(s): Dr Damian Cruse 

University of Registration: University of Birmingham

BBSRC Research Themes: Understanding the Rules of Life (Neuroscience and Behaviour)

Project Outline

The question of what conscious perception is for remains a key, largely unanswered, question for the scientific study of consciousness and indeed for our whole understanding of mind. In fact, a substantial part of the scientific study of consciousness has focused on showing how sophisticated subconscious processing can be, seemingly leaving little room for a “special” purpose for conscious experience.

We have recently presented evidence that the subconscious brain is limited in its capacity to represent episodic information (Avilés, Bowman & Wyble, 2020; Bowman & Avilés (2022); Bowman et al, 2014). By episodic, we are particularly emphasizing the capacity to associate percepts with the passage of time, something that we do so easily consciously that we hardly notice it. This work uses Rapid Serial Visual Presentation (RSVP) to present stimuli on the fringe of awareness. In Avilés et al (2020), we showed that the capacity to consciously perceive a stimulus does not benefit from repeating it, until it has been consciously perceived. Repetition is a key episodic property, i.e. to know that a presentation of a stimulus is a repetition, the brain has to have a memory of a previous episode of experiencing the stimulus.

These characteristics of conscious perception also underlie the effectiveness of our Fringe-P3 brain-computer interface (BCI) Alsufyani ... & Bowman (2019), which has been applied to a number of problems in forensics, e.g. deception detection (Bowman et al, 2014). We are seeking to develop this method further to apply it in police lineups and in medical applications, like objectively testing visual acuity.

The strong theoretical claim is that a specific capacity provided by conscious perception is to lay down freely-recallable episodic memories of previous experiences. We now have extensive behavioural evidence for this. We are thus at a perfect stage to characterise the neural correlates that support this formation of freely-recallable episodic memories. Accordingly, we are proposing a PhD to work on theoretical and/or practical uses of the Fringe-P3 BCI.

Characterising neural correlates, could employ fMRI, MEG or EEG (all of which are available to us), with the latter two particularly relevant because of their high temporal resolution. This direction could take our existing RSVP behavioural paradigms and identify neural components that are engaged when a stimulus presentation leads to the later detection of a repetition. This would give a new way to identify the neural components that are specific to conscious processing, with relevance to debates concerning whether the neural correlates of conscious processing reside in the sensory processing pathways or at a later, brain-scale, stage. Oscillatory correlates of conscious processing and episodic memory formation are of particular interest (Parish, Hanslmayr & Bowman, 2018).

We would also like to explain these findings with the computational theory that underlies our work in this area: the Simultaneous Type/ Serial Token model (Bowman & Wyble, 2007), which is consistent with brain-scale state theories of conscious perception, e.g. the global workspace.

References

Alsufyani ... & Bowman (2019). Breakthrough percepts of famous faces. Psychophysiology, 56(1).

Avilés, Bowman & Wyble (2020). On the limits of evidence accumulation of the preconscious percept. Cognition, 195, 104080.

Bowman & Avilés (2022). No Subliminal Memory for Spaced Repeated Images in RSVP Streams. Psychological Science, 33(11), 1959-1965.

Bowman & Wyble (2007). The simultaneous type, serial token model of temporal attention and working memory. Psychological review 114(1) 38.

Bowman et al (2014). Countering countermeasures: detecting identity lies by detecting conscious breakthrough. PloS one 9(3).

Parish, Hanslmayr & Bowman (2018). The sync/desync model: How a synchronized hippocampus & a desynchronized neocortex code memories. J of Neuroscience 38(14).