The title says it all (almost). Voloh et al found increased theta-gamma cross-frequency coupling between the anterior cingulate and prefrontal cortex during covert shifts of attention.
Theta–gamma coordination between anterior cingulate and prefrontal cortex indexes correct attention shifts
Benjamin Voloh, Taufik A. Valiante, Stefan Everling, and Thilo Womelsdorf
PNAS 2015 ; published ahead of print June 22, 2015, doi:10.1073/pnas.1500438112
Tremblay et al decode the allocation of attention, stimulus location, and saccade from local field potentials in a frequency-dependent matter. Decoding from LFPs was more stable across time than decoding from spikes.
Luo and Maunsell used a specially designed task to show that the only effect of attention in visual cortex is to improve the signal-to-noise ratio of neurons.
See highlight by Timothy J. Buschman:
Kundu et al recorded EEG from humans during a short-term memory task. They found fronto-parietal coherence in different frequencies were associated with different memory functions. Alpha coherence was associated with maintenance of the information in memory. By contrast, the top-down filtering of distractions was associated with beta coherence. This adds to mounting evidence that specific frequency bands are associated with specific types of cortical processing like, for example, beta and top-down control.
A new review by Sprague et al provides an interesting take on cognitive capacity, information loss and attention.
Visual attention mitigates information loss in small- and large-scale neural codes
Thomas C. Sprague, , Sameer Saproo, John T. Serences
Georgia Gregoriou and colleagues review the role of oscillations in the focusing of attention. They suggest that different frequencies reflect the biophysical properties of different cell types and that synchrony allows selective routing of information through these cell populations.
Sacchet et al find that synchronization between the prefrontal and somatosensory cortex may underlie the disengagement of attention. When a cue signaled that a forthcoming tactile stimulus should be ignored, there was first an increase in alpha (7-14 Hz) synchrony between representations of the unattended stimulus, followed by an increase in beta (15-29 Hz) synchrony. This study shows how frequency specific interactions between frontal cortex and sensory cortex may underlie the focusing of attention.
Getting back into work routines, after a holiday break, is something many of us will already have come to grips with in recent weeks. And these routines seem to get busier all the time, as modern technology allows us to perform more and more tasks ourselves, quickly, on our tablets and smart phones. But at what cost? MIT neuroscientist Professor Earl Miller is an expert on divided attention. He argues our addiction to technology is actually making us less efficient.
Virtually all studies of the neural basis of attention to date average effects across independently recorded neurons and across multiple trials. This is obviously artificial because attention has to be allocated on-the-fly, from moment-to-moment, not averaged across time. Trembly et al show that the current locus of attention can be decoded from ensembles of simultaneously recorded prefrontal cortex neurons from single trials. Decoding of these ensembles was stable over weeks. Nice.
Several lines of evidence suggests that searching a visual scene depends on an intrinsic periodicity. We scan the scene by moving the spotlight of attention at regular intervals. For example, Buschman and Miller (2009) found neurophysiological evidence in the frontal eye fields for regular shifts of attention at 25 Hz (i.e., every 40 ms). Dugue et al (2014) have now found evidence in humans using EEG recording and TMS stimulation in humans. They found successful search was associated with oscillations and phase resetting at 6 Hz. TMS applied at different intervals found disruption of search at a periodicity corresponding to 6 Hz. This was slower than reported by Buschman and Miller (2009), but that could be because Dugue et al used a more difficult search task.
This paper:
Theta Oscillations Modulate Attentional Search Performance Periodically
Laura Dugué, Philippe Marque, and Rufin VanRullen Journal of Cognitive Neuroscience, 2014
For further reading:
Buschman, T.J. and Miller, E.K. (2009) Serial, covert, shifts of attention during visual search are reflected by the frontal eye fields and correlated with population oscillations. Neuron, 63: 386-396. View PDF »