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Vocalization in mammals, birds, reptiles, and amphibians occurs with airways that have wide openings to free-space for efficient sound radiation, but sound is also produced with occluded or semi-occluded airways that have small openings to free-space. It is hypothesized that pressures produced inside the airway with semi-occluded vocalizations have an overall widening effect on the airway. This overall widening then provides more opportunity to produce wide-narrow contrasts along the airway for variation in sound quality and loudness. For human vocalization described here, special emphasis is placed on the epilaryngeal airway, which can be adjusted for optimal aerodynamic power transfer and for optimal acoustic source-airway interaction. The methodology is three-fold, (1) geometric measurement of airway dimensions from CT scans, (2) aerodynamic and acoustic impedance calculation of the airways, and (3) simulation of acoustic signals with a self-oscillating computational model of the sound source and wave propagation.

Purpose: Although there is a long history of use of semi-occluded vocal tract gestures in voice therapy, including phonation through thin tubes or straws, the efficacy of phonation through tubes has not been established. This study compares results from a therapy program on the basis of phonation through a flow-resistant tube (FRT) with Vocal Function Exercises (VFE), an established set of exercises that utilize oral semi-occlusions. Method: Twenty subjects (16 women, 4 men) with dysphonia and/or vocal fatigue were randomly assigned to 1 of 4 treatment conditions: (a) immediate FRT therapy, (b) immediate VFE therapy, (c) delayed FRT therapy, or (d) delayed VFE therapy. Subjects receiving delayed therapy served as a no-treatment control group. Results: Voice Handicap Index (Jacobson et al., 1997) scores showed significant improvement for both treatment groups relative to the no-treatment group. Comparison of the effect sizes suggests FRT therapy is noninferior to VFE in terms of reduction in Voice Handicap Index scores. Significant reductions in Roughness on the Consensus Auditory-Perceptual Evaluation of Voice (Kempster, Gerratt, Verdolini Abbott, Barkmeier-Kraemer, & Hillman, 2009) were found for the FRT subjects, with no other significant voice quality findings. Conclusions: VFE and FRT therapy may improve voice quality of life in some individuals with dysphonia. FRT therapy was noninferior to VFE in improving voice quality of life in this study.

Functional MRI of young adults has implicated the striatum in the processing of rewarding and punishing events. To date, only two published experiments (Samanez-Larkin et al., 2007; Schott et al., 2007) have explored similar phenomena in older adults, with both studies emphasizing the anticipation of monetary outcomes. To better understand older participants’ striatal responses to delivered outcomes, we engaged 20 older adults and 13 younger adults in a card-guessing task that rewarded correct guesses with monetary gain and punished incorrect guesses with monetary loss. Overall, the older adults retained most of the typical features of the striatal response, so that activity in the caudate head showed reliable differentiation between rewards and punishments during the 6- to 9-sec postoutcome window. Comparison of the older and younger adults also pointed to some potential aging effects on outcome activity, including reductions in the magnitude and extent of striatal activation, and a trend for the older adults to show a decreased early punishment response. In sum, our data suggest that the signaling of outcome valence remains relatively stable into late adulthood, although more research is needed to understand some subtle changes that might occur across the life span.

Neurons communicate through rapid, all-or-nothing action potential events (“spikes”). Researchers often predict that oscillatory drives will shape spike trains. For example, computational models of Parkinson’s Disease (PD) predict pathological 12-30 Hz spike rhythms. The detection of spike train oscillations presents an algorithmic challenge. We must devise an automated, scalable means of inferring when a noisy point process arose from a rate function that oscillates at a specific frequency, versus one that oscillates at a different frequency, or does not reliably oscillate.To identify oscillations, a naïve algorithm might compute the spike train’s power spectral density (PSD) – the distribution of signal power over frequencies – and detect oscillations as significant PSD peaks, contrasted against an assumed flat baseline. Yet non-oscillatory spike trains can exhibit aperiodic features that render this flat baseline inappropriate.This dissertation investigates whether two common baseline-distorting features can be removed through point process models (PPM), which predict instantaneous spike rates as a function of covariates. I first focus on the “recovery period” (RP): an inevitable, transient post-spike suppression in subsequent spiking. The RP creates global spectral distortion. An established “shuffling” method removes this distortion, but can also reduce the power associated with true spike rhythms. I developed an alternative “residuals” method that accounts for the RP-associated variance in the spike train with a PPM, and generates a corrected PSD from the PPM residuals.In some spike trains, a second, “burst-firing” feature can create further distortion. To accommodate bursts, I developed a “two-state” residuals method. This method infers the timing of burst- and non-burst states, and separately accounts for these states in the PPM.I compared the above methods’ ability to enable accurate oscillation detection with flat baseline-assuming tests. Over synthetic data, the residuals method improved upon the shuffling method’s detection accuracy, and the two-state variant offered further improvement when bursts were simulated. Moreover, in empirical data from a parkinsonian monkey, the residuals PSDs yielded increased incidence of the anticipated pathological oscillations.This work demonstrates that we can use PPMs to remove the distortion that aperiodic features introduce into power spectra, thereby improving the sensitivity and specificity of oscillation detection.

How the brain organizes discrete actions into fluid sequences is a central problem in motor neuroscience. Competing models of basal ganglia (BG) function propose that BG neurons either signal sequence boundaries or encode movements across ordinal positions. Prior studies have largely examined fixed sequences with end-of-sequence rewards, leaving open whether such findings generalize to more naturalistic conditions. We trained four rhesus macaques to perform a visuomotor sequence task requiring four or five out-and-back joystick movements to peripheral targets. Sequences were completed under two conditions: a random condition, in which target order varied across trials, and a fixed condition, in which order was predictable and consistent. Rewards were delivered after each movement, dissociating reward timing from sequence completion. We recorded single-unit activity in arm-related regions of the globus pallidus (GP; n = 458) and primary motor cortex (M1; n = 306). Regression analyses revealed that many neurons in both GP and M1 encoded ordinal position within a sequence. Order effects were more frequent in the fixed condition, but were also present during random sequences. We found no evidence for preferential encoding of sequence initiation or termination in overlearned sequences, in contrast to prior studies reporting start/stop signals in basal ganglia. Weak effects appeared under the random condition in one animal pair, but these did not generalize across animals or conditions. Instead, neurons exhibited heterogeneous order-related responses spanning the full sequence. These results demonstrate that GP neurons, like those in M1, encode ordinal position throughout a sequence rather than acting solely as sequence initiators or terminators. This challenges boundary-specific models of BG function and highlights the BG's broader role in representing serial order during motor sequence production.

Oscillations figure prominently as neurological disease hallmarks and neuromodulation targets. To detect oscillations in a neuron's spiking, one might attempt to seek peaks in the spike train's power spectral density (PSD) which exceed a flat baseline. Yet for a non-oscillating neuron, the PSD is not flat: The recovery period (\"RP\", the post-spike drop in spike probability, starting with the refractory period) introduces global spectral distortion. An established \"shuffling\" procedure corrects for RP distortion by removing the spectral component explained by the inter-spike interval (ISI) distribution. However, this procedure sacrifices oscillation-related information present in the ISIs, and therefore in the PSD. We asked whether point process models (PPMs) might achieve more selective RP distortion removal, thereby enabling improved oscillation detection. In a novel \"residuals\" method, we first estimate the RP duration ( ) from the ISI distribution. We then fit the spike train with a PPM that predicts spike likelihood based on the time elapsed since the most recent of any spikes falling within the preceding milliseconds. Finally, we compute the PSD of the model's residuals. We compared the residuals and shuffling methods' ability to enable accurate oscillation detection with flat baseline-assuming tests. Over synthetic data, the residuals method generally outperformed the shuffling method in classification of true- versus false-positive oscillatory power, principally due to enhanced sensitivity in sparse spike trains. In single-unit data from the internal globus pallidus (GPi) and ventrolateral anterior thalamus (VLa) of a parkinsonian monkey -- in which alpha-beta oscillations (8-30 Hz) were anticipated -- the residuals method reported the greatest incidence of significant alpha-beta power, with low firing rates predicting residuals-selective oscillation detection. These results encourage continued development of the residuals approach, to support more accurate oscillation detection. Improved identification of oscillations could promote improved disease models and therapeutic technologies.

Although the basal ganglia (BG) plays a central role in the motor symptoms of Parkinson's disease, few studies have investigated the influence of parkinsonism on movement-related activity in the BG. Here, we studied the perimovement activity of neurons in globus pallidus internus (GPi) of non-human primates during performance of a choice reaction time reaching task before and after the induction of parkinsonism by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Neuronal responses, including increases or decreases in firing rate, were equally common in the parkinsonian brain as seen prior to MPTP and the distribution of different response types was largely unchanged. The slowing of behavioral reaction times and movement durations following the induction of parkinsonism was accompanied by a prolongation of the time interval between neuronal response onset and movement initiation. Neuronal responses were also reduced in magnitude and prolonged in duration after the induction of parkinsonism. Importantly, those two effects were more pronounced among decrease-type responses, and they persisted after controlling for MPTP-induced changes in the between-trial variability in response timing. Following MPTP the trial-to-trial timing of neuronal responses also became uncoupled from the time of movement onset and more variable in general. Overall, the effects of MPTP on temporal features of GPi responses were related to the severity of parkinsonian motor impairments whereas changes in response magnitude and duration did not reflect symptom severity consistently. These findings point to a previously underappreciated potential role for abnormalities in the timing of GPi task-related activity in the generation of parkinsonian motor signs.

The geometric structure of the cricothyroid (CT) muscle and thyroarytenoid (TA) muscle was quantified in 6 human and 3 canine larynges. Each muscle was divided into a series of fiber bundles. With a 3-dimensional micrometer probe, the coordinates of the origin and insertion of each bundle were measured before dissection. It was found that the mass of the CT muscle in the dog was 1.463 ± 0.280 g, which was significantly greater than the 0.9423 ±0.123 g found in the human. This was a result of the cross-sectional area of the canine CT muscle being 105.3 ± 11.6 mm2 instead of the 73.8 ± 7.4 mm2 found for the human. However, the ratios of CT/TA mass and cross-sectional area between the two groups were not significantly different, suggesting that the two muscles grow proportionally.

Adaptive decision-making requires that options be weighed according to the predicted value of the outcomes that they are likely to produce. Cognitive neuroscientific research has frequently emphasized the importance of the ventromedial prefrontal cortex (VMPFC) for encoding value information. As measured via functional MRI, VMPFC activity has been shown to correlate with the subjective values of explicitly-presented options (e.g., monetary gambles, offered foods) and also with the learned values of stimuli or actions that have been arbitrarily paired with rewards or punishments. Additional work has confirmed VMPFC sensitivity to abrupt changes in option values, particularly when these may be inferred on the basis of regular fluctuations in and/or interrelationships between option-outcome contingencies (e.g., as in serial reversal learning). The use of fixed option alternatives in these settings (e.g., constant choice stimuli) raises the question of whether such rapid updating of value activity can only occur when inferences can rely upon concretely-encoded sensory and motor information. To determine whether any brain region tracks values that may only be inferred via abstract rules, we scanned 17 participants as they completed a series of unique, two-trial discrimination problems in which the stimulus chosen on each Trial 1 was replaced with a novel stimulus of the same reward status on the following Trial 2. Under this protocol, optimal responding required inferences regarding the valence of each unsampled Trial 1 stimulus. Additional problem-wise manipulation of the magnitude of the available gains and losses created a situation in which the specific values of the unsampled stimuli could also be inferred. BOLD-signal analyses revealed activity in the right lateral frontopolar cortex (FPC) that varied linearly with the inferable values of the unsampled Trial 1 stimuli; follow-up analyses confirmed that this effect was not attributable to the influence of the recently-delivered Trial 1 outcomes. Therefore, the results indicate that the brain does encode values that may only be inferred via abstract deduction. The frontopolar focus of this inferred-value activity corroborates and expands upon recent accounts of FPC function, which posit a broader role for this region in monitoring the value of re-directing behavior towards postponed response options.

This chapter considers categories of fundraising event, and examines the key components of an event that typically have to be managed. In a comprehensive fundraising strategy there are four primary reasons for an organization to engage in fundraising events: raising money; identification of prospects; education and cultivation; and recognition. Well‐produced and promoted education events can develop a perception that the hosting organization is at the cutting edge and moving its agenda forward. Key messages sprinkled throughout this social environment can build genuine excitement and enthusiasm. As successful fundraisers know, keeping a current donor is more cost effective than seeking a new one. Whatever the primary goals of an event might be, well‐planned and well‐executed events create a sense of community among supporters that will build or cement a relationship. The chapter concludes by suggesting how the success of events might be evaluated from both the donor and nonprofit perspectives.