Biology subjects

Tierney, A. T.

Publications and source records attributed to Tierney, A. T..

14 recordsLinked to original sources

bioRxiv2025

Attention to Psuedo-Tone Melodies Enhances Cortical but Not Brainstem Responses in Humans

Auditory selective attention, the ability to focus on specific sounds while ignoring competitors, enables communication in complex soundscapes. Though attention clearly modulates cortical responses to sound, whether and where this modulation occurs in subcortical structures remains disputed. Here, we use electroencephalography to record cortical and subcortical (auditory brainstem responses, ABRs) activity during a selective attention task. Human participants attend to a 3-note melody in one pitch range presented to one ear while ignoring a competing, interleaved melody in a different pitch range played to the other ear (Laffere et al., 2020, 2021). The melodies consist of pitch-evoking pseudo-tones formed by convolving a periodic impulse train with a brief tone pip. These stimuli allow us to measure both ABRs (elicited by each individual tone pip within a pseudo-note) and cortical responses (elicited by the onsets of pseudo-notes) simultaneously. We observed robust ABRs, but no evidence of modulation by attention. Conversely, cortical responses, measured by event related potentials (ERPs), demonstrated attentional modulation of the P1-N1 peak. We conclude that attentional modulation within the brainstem is not measurable in the well-defined peaks of the ABR, which themselves reflect processing up to the input stage to the inferior colliculus.

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bioRxiv2025

Neural tracking of melodic prediction is pre-attentive

Musics ability to modulate arousal and manipulate emotions relies upon formation and violation of predictions. Music is often used to modulate arousal and mood while individuals focus on other tasks, suggesting that sophisticated musical prediction may be implicit and obligatory, operating regardless of attention. Here we investigated the role of attention in musical prediction by presenting participants simultaneously with a musical passage in one ear and an audiobook in the other. Participants were asked to attend to either speech or music to perform a recognition memory task. Musical prediction was investigated using a computational model of music which was trained on a corpus of Western music (long-term learning) and/or incrementally on each stimulus (short-term learning). While neural tracking of the acoustics of music, including encoding of note onset and pitch interval size, was enhanced by attention, musical prediction tracked the neural signal robustly regardless of attention. However, although neural tracking of long-term musical prediction based on previously-learned statistical patterns was unaffected by attention, tracking of short-term musical prediction learned from the structure of each stimulus was present only when the music was attended. Thus, attention is crucial for short-term musical learning and prediction but is not required for musical prediction based on long-term stylistic exposure.

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bioRxiv2025

A neuroimaging database combining movie-watching, eye-tracking, sensorimotor mapping, and cognitive tasks

We provide a multimodal naturalistic neuroimaging database (NNDb-3T+), designed to support the study of brain function under both naturalistic and controlled experimental conditions. The database includes high-quality 3T fMRI data from 40 participants acquired during full-length movie-watching and three sensory mapping tasks: somatotopy, retinotopy, and tonotopy. Each participant also completed synchronised eye-tracking during movie-watching and retinotopy, physiological recordings, and a battery of behavioural and cognitive assessments. Data were collected across two MRI sessions and a remote testing session, with all data organised in a BIDS-compliant format. Technical validation confirms high data quality, with minimal head motion, accurate eye-tracker calibration, and robust task-evoked activation patterns. The database provides a unique resource for investigating individual differences, functional topographies, multimodal integration, and naturalistic cognition. All raw and preprocessed data, quality metrics, and preprocessing scripts are publicly available to support reproducible research.

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bioRxiv2025

Spatial coding supports auditory conceptual navigation

Grid cells in human entorhinal cortex encode spatial layouts for real-world navigation, yet their role in conceptual navigation remains unclear. Here we show that mentally transforming tones within a purely auditory pitch-duration space engages spatial circuits, and that such resources are causally necessary. In Experiment 1, participants trained for five days to navigate through a purely conceptual pitch-duration auditory space, then underwent fMRI on Day 6. We observed a six-fold modulation of entorhinal BOLD signals aligned to each participants trajectory angles, similar to grid-cell firing in physical space. Stronger grid-like coding predicted larger training-related gains. In Experiment 2, a new cohort performed the same task under either a spatial or non-spatial interference load. Only the spatial condition selectively disrupted performance on trials requiring mental "movement," indicating a causal reliance on spatial resources. These findings provide evidence that auditory conceptual transformations recruit--and depend on--spatial grid-like computations in the entorhinal-hippocampal system, pointing to a domain-general role for spatial coding in organizing new knowledge along continuous dimensions.

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bioRxiv2024

Systematic changes in neural selectivity reflect the acquired salience of category-diagnostic dimensions

Humans and other animals develop remarkable perceptual and cognitive specializations for identifying, differentiating, and acting on classes of ecologically important signals. This expertise is flexible enough to support diverse perceptual judgments: a voice, for example, simultaneously conveys what a talker says, as well as myriad cues about her identity and state. Expert perception across complex signals thus involves discovering and learning regularities that best inform diverse perceptual judgments, as well as weighting this information flexibly as task demands change. Here, we test whether this flexibility may involve endogenous attentional gain. We use two prospective auditory category learning tasks to relate a complex, entirely novel soundscape to four classes of "alien identity" and two classes of "alien size." Identity, but not size, categorization requires discovery and learning of patterned acoustic input situated in one of two simultaneous, non-overlapping frequency bands. This allows us to capitalize on the coarsely segregated frequency-band-specific channels tiling auditory cortex, using fMRI to ask whether category-relevant perceptual information present in one frequency band is prioritized relative to simultaneous, uninformative information in the other frequency band. Among participants expert at alien identity categorization, we observe prioritization of the identity-diagnostic frequency band that persists even when the diagnostic information becomes irrelevant in the size categorization task. Tellingly, the neural selectivity evoked implicitly in the identity categorization task aligns with that in an independent task, where activation is driven by explicit and sustained selective attention to pure tones in one or the other frequency band. Additionally, the learning trajectories taken to achieve expert-level categorization leave fingerprints on the patterns of neural activity associated with the diagnostic dimension. In all, this indicates that acquiring categories can drive the emergence of acquired attentional gain to category-diagnostic input dimensions.

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bioRxiv2024

Distributional learning drives statistical deafening

Humans and other animals use information about how likely it is for something to happen. The absolute and relative probability of an event influences a remarkable breadth of behaviors, from foraging for food to comprehending linguistic constructions -- even when these probabilities are learned implicitly. It is less clear how, and under what circumstances, statistical learning of simple probabilities might drive changes in perception and cognition. Here, across a series of 29 experiments, we probe listeners sensitivity to task-irrelevant changes in the probability distribution of tones acoustic frequency across tone-in-noise detection and tone duration decisions. We observe that the task-irrelevant frequency distribution influences the ability to detect a sound and the speed with which perceptual decisions about its duration are made. The shape of the probability distribution, its range, and a tones relative position within that range impact observed patterns of suppression and enhancement of tone detection and decision making. Perceptual decisions are also modulated by a newly discovered perceptual bias, with lower frequencies in the distribution more often and more rapidly perceived as longer, and higher frequencies as shorter. Perception is sensitive to rapid distribution changes, but distributional learning from previous probability distributions also carries over. In fact, massed exposure to a single point along the dimension results in seemingly maladaptive loss of sensitivity - occurring entirely in the absence of feedback or reward - along a range of subsequently encountered frequencies. This points to a gain mechanism that suppresses sensitivity to regions along a perceptual dimension that are less likely to be encountered. Significance StatementOrganisms as diverse as honeybees and humans pick up on probabilities in the world around them. People implicitly learn the likelihood of a color, price range, or even syntactic structure. How does statistical learning affect how we detect events and make decisions, especially when probabilities are completely irrelevant to the task at hand, and can change without warning? We find that people learn and track changes in perceptual probabilities irrelevant to a task and that this learning drives dynamic shifts in perception characterized by graded effects of enhancement - and primarily - suppression across acoustic frequency. This can result in a remarkably long- lived diminishment of perceptual sensitivity that seems maladaptive but may instead reflect use of likelihood to guide and sharpen perception.

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bioRxiv2022

Salient sounds distort time perception and production

The auditory world is often cacophonous, with some sounds capturing attention and distracting us from our goals. Despite the universality of this experience, many questions remain about how and why sound captures attention, how rapidly behavior is disrupted, and how long this interference lasts. Here we use a novel measure of behavioral disruption to test two predictions made by models of auditory salience. First, models predict that goal-directed behavior is disrupted at points in time that feature a high degree of spectrotemporal change. We find that behavioral disruption is precisely time-locked to the onset of distracting sound events: participants tapping to a metronome speed up immediately after the onset of distractors. Moreover, this response is greater for more salient sounds (larger amplitude) and sound changes (greater pitch shift). Second, models predict that different auditory features are combined into an overarching salience map. We find that the time course of behavioral disruption is highly similar after acoustically disparate sound events, suggesting overlapping mechanisms of attentional capture: both sound onsets and pitch shifts of continuous background sounds speed responses at 750 ms, with these effects dying out by 1750 ms. These temporal distortions can be observed using only data from the first trial across participants. A potential mechanism underlying these results is that arousal increases after distracting sound events, leading to an expansion of time perception, and causing participants to misjudge when their next movement should begin. Significance StatementThe noisy world constantly challenges our pursuit of goals. When driving, for example, a cacophony of mechanical, musical, and conversational sounds surrounds us and can wrench our focus away from the road. While the physiological signatures of auditory attentional capture are well researched, we know surprisingly little about how sound affects moment-to-moment behavior: How quickly do sounds affect our actions, how transient is the effect, and how is action affected by changes in sound properties? Here we use a synchronized tapping paradigm to show that loud sounds and large acoustic changes cause rapid distortions in time perception. However, these distortions were corrected within 2 seconds, showing that goal-directed behavior is transiently vulnerable yet ultimately resilient in the face of distraction.

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bioRxiv2021

Dimension-Selective Attention and Dimensional Salience Modulate Cortical Tracking of Acoustic Dimensions

Some theories of auditory categorization suggest that auditory dimensions that are strongly diagnostic for particular categories - for instance voice onset time or fundamental frequency in the case of some spoken consonants - attract attention. However, prior cognitive neuroscience research on auditory selective attention has largely focused on attention to simple auditory objects or streams, and so little is known about the neural mechanisms that underpin dimension-selective attention, or how the relative salience of variations along these dimensions might modulate neural signatures of attention. Here we investigate whether dimensional salience and dimension-selective attention modulate cortical tracking of acoustic dimensions. In two experiments, participants listened to tone sequences varying in pitch and spectral peak frequency; these two dimensions changed at systematically different rates. Inter-trial phase coherence (ITPC) and EEG signal amplitude at the rates of pitch and spectral change allowed us to measure cortical tracking of these dimensions. In Experiment 1, tone sequences varied in the size of the pitch intervals, while the size of spectral peak intervals remained constant. Neural entrainment to pitch changes was greater for sequences with larger compared to smaller pitch intervals, with no difference in entrainment to the spectral dimension. In Experiment 2, participants selectively attended to either the pitch or spectral dimension. Neural entrainment was stronger in response to the attended compared to unattended dimension for both pitch and spectral dimensions. These findings demonstrate that bottom-up and top-down attentional mechanisms enhance the cortical tracking of different acoustic dimensions within a single sound stream.

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bioRxiv2021

Slow phase-locked endogenous modulations support selective attention to sound

To make sense of complex soundscapes, listeners must select and attend to task-relevant streams while ignoring uninformative sounds. One possible neural mechanism underlying this process is alignment of endogenous oscillations with the temporal structure of the target sound stream. Such a mechanism has been suggested to mediate attentional modulation of neural phase-locking to the rhythms of attended sounds. However, such modulations are compatible with an alternate framework, where attention acts as a filter that enhances exogenously-driven neural auditory responses. Here we attempted to adjudicate between theoretical accounts by playing two tone steams varying across condition in tone duration and presentation rate; participants attended to one stream or listened passively. Attentional modulation of the evoked waveform was roughly sinusoidal and scaled with rate, while the passive response did not. This suggests that auditory attentional selection is carried out via phase-locking of slow endogenous neural rhythms.

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bioRxiv2021

Prosodic categories in speech are acoustically multidimensional: evidence from dimension-based statistical learning

Segmental speech units such as phonemes are cued by multiple acoustic dimensions (e.g. F0 and duration), but dimensions do not carry equal perceptual weight. The relative perceptual weights of acoustic speech dimensions are not fixed but vary with context. For example, when speech is altered to create an accent in which two acoustic dimensions are correlated in a manner opposite that of long-term experience, the dimension that carries less perceptual weight is down-weighted to contribute less in category decisions. It remains unclear, however, whether this short-term reweighting is limited to segmental categorization, or if it extends to categorization of suprasegmental features which span multiple phonemes, syllables, or words, which would suggest that such "dimension-based statistical learning" is a widespread phenomenon in speech perception. Here we investigated the relative contribution of two acoustic dimensions to word emphasis. Participants categorized instances of a two-word phrase pronounced with typical covariation of fundamental frequency (F0) and duration, and in the context of an artificial accent in which F0 and duration (established in prior research on English speech as primary and secondary dimensions, respectively) covaried atypically. When categorizing accented speech, listeners rapidly down-weighted the secondary dimension (duration) while continuing to rely on the primary dimension (F0). This result indicates that listeners continually track short-term regularities across speech input and dynamically adjust the weight of acoustic evidence for suprasegmental categories. Thus, dimension-based statistical learning appears to be a widespread phenomenon in speech perception extending to both segmental and suprasegmental categorization.

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bioRxiv2020

Brief Report: Test-Retest Reliability of Explicit Auditory Processing Measures

In this brief report, we examined the test-retest reliability of our in-house explicit auditory processing measures in the context of 30 L1 and L2 English users. The participants took the same test battery which consisted of a total of four discrimination tasks (encoding acoustic details of formant, pitch, duration, and rise time) and two reproduction tasks (repeating novel melodic and rhythmic patterns) at Days 1 and 2. According to the results, the participants initial and second test scores demonstrated medium-to-large associations (r = .562-.907). The results suggest that the tests can tap into various dimensions of individuals auditory acuity and integration abilities.

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bioRxiv2020

Effects of language experience on domain-general perceptual strategies

Speech and music are highly redundant communication systems, with multiple acoustic cues signaling the existence of perceptual categories. This redundancy makes these systems robust to the influence of noise, but necessitates the development of perceptual strategies: listeners need to decide the importance to place on each source of information. Prior empirical work and modeling has suggested that cue weights primarily reflect within-task statistical learning, as listeners assess the reliability with which different acoustic dimensions signal a category and modify their weights accordingly. Here we present evidence that perceptual experience can lead to changes in cue weighting which extend across tasks and across domains, suggesting that perceptual strategies reflect both global biases and local (i.e. task-specific) learning. In two experiments, native speakers of Mandarin (N=45)--where pitch is a crucial cue to word identity--placed more importance on pitch and less importance on other dimensions compared to native speakers of non-tonal languages English (N=45) and Spanish (N=27), during the perception of both second language speech and musical beats. In a third experiment, we further show that Mandarin speakers are better able to attend to pitch and ignore irrelevant variation in other dimensions compared to English and Spanish speakers, and even struggle to ignore pitch when asked to attend to other dimensions. Thus, an individuals idiosyncratic auditory perceptual strategies reflect a complex mixture of congenital predispositions, task-specific learning, and biases instilled by extensive experience in making use of important dimensions in their native language.

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bioRxiv2019

Reduced functional connectivity between left frontal and right auditory cortices during speech perception in congenital amusia.

Individuals with congenital amusia have a lifelong history of unreliable pitch processing. Accordingly, they downweight pitch cues during speech perception (even large, obvious ones) and instead rely on other dimensions such as duration. We investigated the neural basis for this strategy. During fMRI, individuals with amusia and controls (N=30) matched auditory and visual sentences using pitch and duration cues. A data-driven analysis procedure detected prominent reductions in functional connectivity in the amusia group, between left prefrontal language-related regions (inferior and middle frontal gyrus/DLPFC) and right hemisphere pitch-related regions (auditory and anterior insular cortex). Functional connectivity levels were correlated with prosodic cue weights measured outside the scanner. Furthermore, group differences in functional connectivity between these regions was not present during a control task (passive listening to tones). Our results suggest that individuals compensate for differences in the reliability of perceptual dimensions by regulating functional connectivity between task-relevant frontal and perceptual regions.

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bioRxiv2018

Redundancy makes music and speech robust to individual differences in perception

In speech, linguistic information is conveyed redundantly by many simultaneously present acoustic dimensions, such as fundamental frequency, duration and amplitude. Listeners show stable tendencies to prioritize these acoustic dimensions differently, relative to one another, which suggests individualized speech perception strategies. However, it is unclear what drives these strategies, and more importantly, what impact they have on diverse aspects of communication. Here we show that such individualized perceptual strategies can be related to individual differences in perceptual ability. In a cue weighting experiment, we first demonstrate that individuals with a severe pitch perception deficit (congenital amusics) categorize linguistic stimuli similarly to controls when their deficit is unrelated to the main distinguishing cue for that category (in this case, durational or temporal cues). In contrast, in a prosodic task where pitch-related cues are typically more informative, amusics place less importance on this pitch-related information when categorizing speech. Instead, they relied more on duration information. Crucially, these differences in perceptual weights were observed even when pitch-related differences were large enough to be perceptually distinct to amusic listeners. In a second set of experiments involving musical and prosodic phrase interpretation, we found that this reliance on duration information allowed amusics to overcome their perceptual deficits and perceive both speech and music successfully. These results suggest that successful speech - and potentially music - comprehension is achieved through multiple perceptual strategies whose underlying weights may in part reflect individuals perceptual abilities.

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