Vestigial Auriculomotor Activity Indicates the Direction of Auditory Attention in Humans

Abstract

1It is commonly assumed that, unlike dogs and cats, we humans do not make 2 ear movements when focusing our attention reflexively toward novel sounds or 3 voluntarily toward those that are goal-relevant. In fact, it has been suggested 4 that we do have a pinna-orienting system. Although this system became ves-5 tigial about 25 million years ago, it still exists as a "neural fossil" within the 6 brain. Consistent with this hypothesis, we demonstrate for the first time that the 7 direction of auditory attention is reflected in the sustained electrical activity of 8 muscles within the vestigial auriculomotor system. 9 Surface electromyograms (EMGs) were taken from muscles that either move 10 the pinna or alter its shape. To assess reflexive, stimulus-driven attention we 11 presented novel sounds from speakers at four different lateral locations while the 12 participants silently read a boring text in front of them. To test voluntary, goal-13 directed attention we instructed participants to listen to a short story coming from 14 one of these speakers, while ignoring a competing story from the corresponding 15 speaker on the opposite side. 16 In both experiments, EMG recordings showed larger activity at the ear on the 17 side of the attended stimulus, but with slightly different patterns. Upward move-18 ment (perking) differed according to the lateral focus of attention only during 19 voluntary orienting; rearward folding of the pinna's upper-lateral edge exhibited 20 such differences only during reflexive orienting. The existence of a pinna-orienting 21 system in humans, one that is experimentally accessible, offers opportunities for 22 basic as well as applied science. It could lead to a better understanding of the 23 evolution of auditory attention and support the near real-time decoding of audi-24 tory attention in technical applications, for example, for attentionally controlled 25 hearing aids that preferentially amplify sounds the user is attempting to listen 26 to. 27 Introduction 28 A review of research (Hackley, 2015) on pinna-orienting in humans identified three rel-29 evant findings scattered across the preceding 100-or-so years. The first was Wilson's 30 (1908) (Wilson, 1908) oculo-auricular phenomenon, in which shifting the gaze hard to 31 one side elicits a 1 to 4 mm deflection of the lateral rim of both ears. The relevance to 32 spatial attention is uncertain, though, because the relation between the side with the 33 largest ear movement and that to which gaze is directed has been weak and inconsistent & Hillyard, 1987) of the bilateral postauricular muscle (PAM) reflex (onset latency = 37 10 ms) to acoustic onset transients. Increased amplitudes were observed when subjects 38 directed their attention to a stream of tones on the same side as the recorded muscle 39 while ignoring a competing, contralateral stream. Comparisons across left/right stim-40 ulus, attention, and PAM combinations localized modulation to the motor limb of the 41 reflex arc. This pattern could indicate that the muscle behind...

Fast EEG-based decoding of the directional focus of auditory attention using common spatial patterns

“…10. directive ear movements [37]). However, there are several indications that the CSP filters do not exploit these effects and indeed focus mainly on neural activity.…”

“…As ear movements spectrally (β-and γ-band) overlap with the information used by the CSPs, it is more difficult to exclude the exploitation of subtle ear movements [37]. There are, however, two counterindications.…”

Heading direction tracks internally directed selective attention in visual working memory

“…Moreover, from an evolutionary perspective, it is conceivable that our ability to orient internally evolved gradually from external orienting behaviours of the head and eyes – maybe relying on overlapping neural circuitry 28 . From this perspective, the observed subtle bias in head- and eye-movements may reflect an inevitable ‘spill over’ from activating neural circuitry that has evolved to orient both internally and externally 29 .…”

Lagrangian Motion Magnification with Double Sparse Optical Flow Decomposition

“…in [16,21], but also to attenuate them separately or completely remove all movement, see [3,17]. An advantage of Lagrangian methods is that the estimated motion information can not only be used for the motion magnification task, but allows subsequent quantitative assessment [18,30].…”

“…On a more general scope, micromovements of the face and head can contain other important physiological and psychophysiological information: The movement of the head can contain cues on heart rate [29], movement of the mouth can be applied for audiovisual speech recognition in noisy environments [24], and micromovements of the ear can contain cues on audio stimuli [30]. While many of the analysis methods fall back on optical flow methods for analysis, there are not many annotated datasets for specific, local movements.…”