[CTN] CTN seminar: Jan 25th, Dr. Thilo Womelsdorf, 3:30pm, PAS 2464

[Matthijs van der Meer]

Dear all,

Please join us for next Tuesday's CTN seminar by Dr. Thilo Womelsdorf,
from the University of Western Ontario.

Time and place are the usual, 3.30pm on Tuesday in PAS 2464.

If you would like to submit or revise a 1-slide snapshot of past,
current, or future work, please send this to me before the day of the
seminar. As before, these slides will run on a looping show after the
seminar, to stimulate discussion over some drinks and snacks.

If you would like to meet with Thilo and/or come to dinner, please let
me know!

Thanks,

- Matt



Title: Topography and mechanisms of valuation and attentional control
processes in macaque fronto-cingulate cortex

Abstract: Attentional control describes network processes which select
sensory information most relevant in a given task context. Controlling
which stimulus is attended should thus originate from neurons encoding
(i) the relevance, i.e. the expected value, of a stimulus, as well as
(ii) contextual rules on how to attentionally select target stimuli.
Both processes of attentional control, selective value predictions and
instantiation of attentional rules, likely arise from separable nodes in
fronto-cingulate cortex: The anterior cingulate cortex (ACC) is
implicated to convey value predictions (e.g. "stimulus A promises reward
outcome X"), while anterior-lateral prefrontal cortex (alPFC) likely
initiates conditional rules including cue-target association rules (e.g.
"if cue is red, then target is stimulus A").

At the neuronal level, both control processes need coordination ensuring
that only those neurons become activated, which biases the larger
attention-network to prioritize target processing. One neuronal
mechanism linking selective target encoding neurons to a functional
assembly is neuronal synchronization. We therefore measured in two
macaques and across the medial-to-lateral extent of the fronto-cingulate
whether phase synchronization of neuronal spiking activity to the LFP
conveyed selective information about the expected value of attentional
targets and about the cue-to-target attentional rule.

We find that for high-value targets ACC neurons selectively synchronized
to a theta rhythm, suggestive of a limbic origin. The same neuronal
cluster engaged in beta-rhythmic synchronization when attention shifted
to a low-value target, i.e. when stronger control of attentional rule
information needed to dominate against motivational biases. Consistent
with this interpretation, beta synchronization was particularly strong
in alPFC during attention shifts to a low-value target. These results
reveal a switch-like behavior of neuronal synchronization, which was
frequency-specific and anatomically-confined and could reflect the
dynamic instantiation of a target encoding neuronal assembly.