Disruption in neural phase synchrony is related to identification of inattentional deafness in real-world setting

Individuals often have reduced ability to hear alarms in real world situations (e.g., anesthesia monitoring, flying airplanes) when attention is focused on another task, sometimes with devastating consequences. This phenomenon is called inattentional deafness and usually occurs under critical high workload conditions. It is difficult to simulate the critical nature of these tasks in the laboratory. In this study, dry electroencephalography is used to investigate inattentional deafness in real flight while piloting an airplane. The pilots participating in the experiment responded to audio alarms while experiencing critical high workload situations. It was found that missed relative to detected alarms were marked by reduced stimulus evoked phase synchrony in theta and alpha frequencies (6–14 Hz) from 120 to 230 ms poststimulus onset. Correlation of alarm detection performance with intertrial coherence measures of neural phase synchrony showed different frequency and time ranges for detected and missed alarms. These results are consistent with selective attentional processes actively disrupting oscillatory coherence in sensory networks not involved with the primary task (piloting in this case) under critical high load conditions. This hypothesis is corroborated by analyses of flight parameters showing greater maneuvering associated with difficult phases of flight occurring during missed alarms. Our results suggest modulation of neural oscillation is a general mechanism of attention utilizing enhancement of phase synchrony to sharpen alarm perception during successful divided attention, and disruption of phase synchrony in brain networks when attentional demands of the primary task are great, such as in the case of inattentional deafness

The improviser and the improvised: The relationship between neural and musical structures, and the role of improvisation

This paper investigates the intersection of well-formed structures in music with neurocognitive structures and responses in expert musicians. As musicology has explored musical structures to great length, and neuroscience has begun exploring the neural structures that underscore musical experiences, little research has been done to investigate how functional differences in music structure relate to neural structure. As the overwhelming majority of professional performing musicians have regular contact with music structures in applied and theoretical contexts, it is of interest to understand how the functions of these music structures correlate with neurocognitive structures when listening to or performing music. Furthermore, this work aims to explore how experience with improvisation drives the relationship between the function of musical structures and its neural correlates. This work is motivated by the idea that improvising musicians regularly employ techniques to change the prescribed music structure to fit the dynamics of the musical environment. This implies that expert improvising musicians may view the function of musical structures differently from musicians who do not interact with music structure in such a way. As such, an EEG experiment was conducted to investigate this relationship. Forty-one musicians performed an oddball task where they listened to 3-chord chord progressions, responding to any and all oddball chord progressions on a computer keyboard. The middle chord could be an exemplar oddball (an inversion of standard chord) or a functional oddball (a different class from the standard chord). The results found that musicians with more improvisational experience produced a greater response to functional deviants, indicating that improvisation experience plays a role in what category of structural information is more prevalent to the musician. These results were consistent across behavioral and neural measures, which were also correlated with one another. Chapters 1 and 2 provide background on music structure, improvisation, neuroscience, and the intersection of the three. Chapters 3 and 4 explain the experiment and the results. Chapter 5 integrates these results into the larger questions regarding improvisation, creativity research, and considers the pragmatic applications of improvisation training. Finally, this paper proposes another study that addresses deeper questions about neural and music structural correlations

Stimulus-specific adaptation and deviance detection in the auditory cortex

Tesis por compendio de publicaciones[EN] Neurons in primary auditory cortex, thalamus and midbrain show stimulus-specific adaptation (SSA), a reduction in response to repetitive stimuli that does not affect neuronal responses to deviant tones. This has been proposed as a neuronal correlate of the mismatch negativity (MMN), a special evoked potential in response to deviant tones. However, three important requirements remain to be demonstrated in order to support the SSA-MMN link: (1) MMN is generated mainly within higher-order auditory cortical areas, whereas cortical SSA has only been recorded in A1 of different species. (2) MMN is a mid-long latency response, peaking between 100-200 ms in humans, whereas SSA has only been observed in early responses of A1 neurons. And finally, (3) neuronal responses to oddball stimulation have not been tested for deviance detection–enhancement of responses to deviant events—in addition to SSA, which is an essential property of any bona-fide mismatch response. In this study, I set specific objectives to investigate the relation between SSA and MMN, and moreover, I will test the Hierarchical Predictive Coding account for the MMN at the neuronal level, showing that single neuron responses to oddball stimulation represent prediction error, which is hierarchically organized along the auditory system