Our fourth group meeting took place on 25/03. It was held online (using zoom) due to the ongoing COVID-19 pandemic. The meeting was led by one of the group organizers, Gal Vishne. This was our first meeting discussing the relation of brain rhythms to cognition. Our goal was to review a novel framework for how attention is carried out by the primate brain named the “rhythmic theory of attention” (Reviewed in Fiebelkorn & Sabine Kastner 2019). We planned to discuss the main empirical findings leading to this theory (Reported in Fiebelkorn, Pinsk & Kastner 2018), and its place in the current research landscape.

The meeting started with an overview of the concept of attention and its many facets. We distinguished between covert and overt attention, endogenous and exogenous attention and separated between spatial attention, feature based attention and temporal attention. We focused this meeting on overt endogenous spatial attention, since this topic has been researched the most, but we tried to connect our conclusions to other forms of attention when possible. To understand the connection to rhythms we reviewed a pioneering 2012 study by Ayelet Landau showing rhythmic behavior in an attentional task (Landau & Fries 2012). We then discussed briefly the known neural correlates of attention, to prepare us for understanding the novel contributions behind the “rhythmic theory of attention”. Lastly, we discussed established functional associations of the main frequency bands used in human and primate LFP studies, which were crucial for the conceptualization of the main theory.

 At this point we were finally prepared to discuss the main theory and the empirical evidence behind it. The main contribution of the theory is in the division of sustained attention into two opposing phases – a “sampling phase”, where sensory processing is enhanced in a specific (attended) location and a “shifting phase”, where attentional shifts are more likely and there is less sensory processing. Each phase is associated with different behavioral outcomes and different active frequency bands at the main hubs of the attentional network. We agreed that the associations between the different frequencies are relatively sound, but the cognitive capacity discussed requires more refined specification, and the underlying neural implementation is unclear. Importantly – we realized the behavioral effect is very small (less than 5% peak to peak), so it is important to understand how prominent the phenomenon of rhythmic attention is relative to other behavioral changes (e.g. the >20% increase in HR over time, likely related to the hazard function), and how common it is in natural behavior.

The meeting opened many deep questions which we plan to discuss in future meetings:

1. The theory we discussed this meeting is related mostly to spatial and feature based attention, but rhythms have been implicated in temporal attention too. We decided to investigate this in more detail next meeting.
2. Timing and oscillations: Oscillations are an intuitive analogy when thinking about time, but there also many theories that don’t rely on oscillations. This is an interesting case to investigate the explanatory benefit gained from oscillations.
3. The cerebellum is strongly related to eye movements. Covert (and overt obviously) visual attention are also related to the eye movements. What do we know about the cerebellum with relation to selective attention?
4. Some figures from the paper we read suggest that there may have been a change in the slope of the power spectrum (spectral tilt) responsible for some of the effects we observed. We plan to discuss analytical methods for identifying this tilt and review studies of how it relates to cognition.

References

Fiebelkorn, I. C., Pinsk, M. A., & Kastner, S. (2018). A dynamic interplay within the frontoparietal network underlies rhythmic spatial attention. Neuron, 99(4), 842-853.

Fiebelkorn, I. C., & Kastner, S. (2019). A rhythmic theory of attention. Trends in cognitive sciences, 23(2), 87-101.

Landau, A. N., & Fries, P. (2012). Attention samples stimuli rhythmically. Current biology, 22(11), 1000-1004.

 

Participants:

Gal Vishne

Nir Ofir

Nora Vrieler

Moran Aharoni

Ruoyi Cao

Noa Rahamim

Lena Gorina

Lorenzo Guarnieri

Yaron Cohen