Thesis--Cologne, 1976. / Vita. Includes bibliographical references (p. 180-187).

Thesis--Cologne, 1976. / Vita. Includes bibliographical references (p. 180-187).

Hearing in noise is facilitated by the auditory system’s ability to separate sound into small auditory segments. Separation of sound is achieved using an auditory mechanism called temporal resolution that codes for small silent gaps in an acoustic stimulus. This thesis proposes a new method for measuring temporal resolution and applied it to a small pilot group of individuals with tinnitus. Previous studies have postulated that tinnitus can “fill” in silent gaps thereby making gap detection more difficult. This was shown in studies using the gap prepulse inhibition acoustic startle where the amplitude of a startle response indicates the subject’s ability to detect a small silent gap. However studies using behavioural gap detection do not show significant differences in people with reported tinnitus. Thus the behavioural evidence does not appear to support the hypothesis that tinnitus can “fill” in silent gaps. In this thesis a new method was proposed for measuring neural gap detection: the mismatch negativity response (MMN). The mismatch negativity responses were compared to behavioural measures of gap detection in thirty-five normal hearing adults: five with reported tinnitus and thirty without tinnitus. They underwent recordings to gapped stimuli ranging from 2- to 40-ms gap durations. The stimuli were either a broadband or narrowband noise presented in the absence or presence of a filler noise. Results of these experiments found the broadband and narrowband noises elicited MMNs to silent gaps. The amplitude of the MMN increased with larger gap durations. When filled, the amplitude of the entire waveform was proportionally reduced for all gap durations. However, for the tinnitus group the filler reduced the largest gap durations elicited MMNs amplitudes disproportionately more than for the smaller gap durations. The high and low filler noise reduced the amplitude of the 40-ms gap MMNs. This was not reflective in the behavioural performance of gap detection as there were no significant group differences. These studies show that neural gap detection can be measured using mismatch negativities. Reduced behavioural gap detection performance is reflected by a smaller amplitude of the MMN for suprathrehold gaps. This was shown in both normal hearing participants with elevated behavioural gap detection thresholds and participants with tinnitus. Therefore, electrophysiological recordings to gaps may provide further information on the underlying mechanisms involved in impaired gap detection that may not be captured by behavioural measures alone.

Organizational work is characterized by positive as well as often negative work behaviors from employees. The same may be said of work done in virtual teams, where computer-mediated communication among team members can be particularly uncivil and inflammatory (Wilson, Straus, & McEvily, 2006). Accordingly, trust has been theorized as more difficult to develop in these types of teams compared to traditional face to face teams. Using a computer simulation of a collaborative team task, this study examined how individuals in virtual teams integrate conflicting pieces of positive and negative information about a teammate into one overall rating of trust. Data were analyzed from 240 individuals to examine the influence of these behaviors on levels of trust toward a target teammate. Evidence of trust quickly developing and declining, i.e., the dynamic nature of trust, in a virtual team was observed. Secondly, the negativity effect was found, where a negative behavior was given more weight in ratings of trust than a positive behavior. Next, the hierarchically restrictive schema was offered as a plausible explanation for the negativity effect due to creating asymmetrical expectations of subsequent behavior based on an initially observed behavior. Lastly, a significant negativity effect was not found when the two behaviors were performed, one each, by a pair of unrelated persons or by a pair of related persons with entitativity.

The present investigation analyses the political thought of the Czech philosopher Jan Patočka. It focuses on the question of how we are to understand political life: what are its distinguishing features and how we are to circumscribe it conceptually. According to Patočka the experience of politics is one characterized by a loss of meaning, a loss of a foundation or principle that could lend stability to our lives. It is an experience of a tremor by and through which the foundations of our experience are shaken. Philosophy’s political task is, however, not to provide any foundation for political life, but rather to address the question of why man is inclined to posit metaphysical foundations and why refuge in ideological principles is sought. Philosophy must instead engage with the groundlessness and negativity permeating human existence as such. In order to provide an analysis of human existence, and how this very groundlessness of existence is exposed in politics, Patočka calls for an “a-subjective phenomenology” that abandons the traditional notion of the subject and of subjectivity. An “a-subjective” phenomenological analysis is central for the present investigation. The author shows that it is only by and through Patočka’s a-subjective phenomenology that his political thought can be understood; out of his distinctive phenomenological analyses, the negativity, instability and groundlessness of human existence is brought to the fore. Politically, this negativity manifests itself in two phenomena, which, when taken together, constitute the very bedrock for politics: freedom and human coexistence. Human existence is neither stable nor self-sufficient.  On the contrary, it is always already exposed to others, always already engaged in the self-transcending movement of its freedom. Freedom and coexistence are in this respect two interrelated expressions of the inherent negativity of human existence and two phenomena that, accordingly, occupy a privileged position in this study. The author seeks to show that it is by way of an in-depth analysis of freedom and coexistence that the question of politics can be addressed in the work of Patočka since they give testament to the trembling, unnerving, and disorienting nature of politics. / Loss of Grounds as Common Ground

Error-related negativity (ERN) is an event-related potential elicited by the commission of errors. It appears as a negative deflection peaking between 50ms and 100ms after an erroneous response. Previous literature demonstrated that individuals who suffer from either anxiety or depression display a higher ERN amplitude compared to a control group. It has also been shown that people with ADHD display a lower ERN amplitude. Based on these findings, we investigated the relationships between these three disorders and their effects on the amplitude of the ERN. We recruited thirty-one students at East Tennessee State University and gathered data on their level of anxiety, depression, and ADHD through completion of three surveys: the Beck Anxiety Inventory, Beck Depression Inventory, and the ADHD self-report scale. Subsequently, participants were asked to perform a modified Flanker task while their EEG was collected using a 32-channel EEG cap. ERN amplitude for error responses was significantly higher than ERN amplitude for correct responses. In contrast with previous literature, no significant influence on the ERN was observed due to anxiety, depression, or ADHD. Additional research on the topic with larger sample size and different diagnostic procedures may be necessary to further investigate the phenomenon.

The measurement of electrical activity at the scalp using EEG can provide great insight into cognition and information processing. For example, event-related potentials (ERPs) are positive or negative deflections that correspond to a stimulus or event. These ERPs can reflect error processing and attentional processes associated with a stimulus. Specifically, error-related negativity and feedback-related negativity (ERN, FRN), are related to performance/conflict monitoring. Furthermore, the P300 ERP reflects attentional processes in response to target stimuli. Previous research examining the P300 component on a complex learning task has demonstrated increased P300 amplitude in response to violations of participants’ expectations about task events. The current study extends this research by examining ERN and FRN amplitudes on trials with incorrect behavioral responses throughout the same learning task. Pilot data has been collected from four participants. Participants wore an electrode cap with 32 electrodes to record EEG data while completing a paired associate task. Pilot data has demonstrated an increased ERN amplitude 50ms after error commission on incorrect trials. The ERN and FRN amplitudes were greater for incorrect trials than for correct trials. Larger P300 amplitudes were also observed for the incorrect trials than for the correct trials. This extension upon previous findings provides further insight into the role of performance monitoring and error processing in learning.

The P300-based brain-computer interface (BCI) is an extension of the oddball paradigm, and can facilitate communication for people with severe neuromuscular disorders. It has been shown that, in addition to the P300, other event-related potential (ERP) components have been shown to contribute to successful operation of the P300 BCI. Incorporating these components into the classification algorithm can improve the classification accuracy and information transfer rate (ITR). In this paper, a single character presentation paradigm was compared to a presentation paradigm that is based on the visual mismatch negativity. The mismatch negativity paradigm showed significantly higher classification accuracy and ITRs than a single character presentation paradigm. In addition, the mismatch paradigm elicited larger N200 and N400 components than the single character paradigm. The components elicited by the presentation method were consistent with what would be expected from a mismatch paradigm and a typical P300 was also observed. The results show that increasing the signal-to-noise ratio by increasing the amplitude of ERP components can significantly improve BCI speed and accuracy. The mismatch presentation paradigm may be considered a viable option to the traditional P300 BCI paradigm.

No description available.

No description available.