Are brain oscillations related to visual consciousness?

Just the other day I crossed paths with this fantastic review of oscillatory correlates of conscious perception by Gallotto et al. (2017). You can have the information more in detail below about the paper:

Front Psychol. 2017; 8: 1147. Published online 2017 Jul 7. DOI: 10.3389/fpsyg.2017.01147

Oscillatory Correlates of Visual Consciousness

Stefano Gallotto, Alexander T. Sack, Teresa Schuhmann, and Tom A. de Graaf

Abstract. Conscious experiences are linked to activity in our brain: the neural correlates of consciousness (NCC). Empirical research on these NCCs covers a wide range of brain activity signals, measures, and methodologies. In this paper, we focus on spontaneous brain oscillations; rhythmic fluctuations of neuronal (population) activity which can be characterized by a range of parameters, such as frequency, amplitude (power), and phase. We provide an overview of oscillatory measures that appear to correlate with conscious perception. We also discuss how increasingly sophisticated techniques allow us to study the causal role of oscillatory activity in conscious perception (i.e., ‘entrainment’). This review of oscillatory correlates of consciousness suggests that, for example, activity in the alpha-band (7–13 Hz) may index, or even causally support, conscious perception. But such results also showcase an increasingly acknowledged difficulty in NCC research; the challenge of separating neural activity necessary for conscious experience to arise (prerequisites) from neural activity underlying the conscious experience itself (substrates) or its results (consequences).

From my perspective, this paper…

  • …brings up to the table the current literature that relates different parameters of brain oscillations (e.g., power, phase, coherence…) to behavioural fluctuations in visual consciousness tasks.
  • …spreads some light into the neurocognitive events that happen in the conscious perception process, from the perception of visual input (e.g., visual flash) to the eventual button precess reacting to that very input (e.g., reaction time).
  • …determines that ongoing brain oscillations are involved in this eventual process and, thus, in conscious (visual) perception.
  • …highlights that despite the current research evidence yet no single oscillatory mechanism emerges as the core candidate for conscious processing.
  • …concludes that different parameters of oscillatory activity, frequency, power, phase, and coherence, should be evaluated to eventually distinguish their roles and contributions.

So, after having read this paper I started wondering whether alpha oscillations have actually the role that alpha theories claim that they have and whether we can actually build a bridge between brain oscillations and fluctuations in behaviour and modulate behaviour depending on different parameters of brain oscillations. I will leave this for another post and continue thinking about it and see where it brings me.  I’ll keep you posted!


Feature image from Pexels – CC0.

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