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In the adult auditory system, loss of input resulting from peripheral deafferentation is well known to lead to plasticity in the central nervous system, manifested as reorganization of cortical maps and altered activity throughout the central auditory pathways. The auditory system also has strong afferent and efferent connections with cortico-limbic circuitry including the prefrontal cortex and the question arises whether this circuitry is also affected by loss of peripheral input. Recent studies in our laboratory showed that PFC activation can modulate activity of the auditory thalamus or medial geniculate nucleus (MGN) in normal hearing rats. In addition, we have shown in rats that cochlear trauma resulted in altered spontaneous burst firing in MGN. However, whether the PFC influence on MGN is changed after cochlear trauma is unknown. We investigated the effects of electrical stimulation of PFC on single neuron activity in the MGN in anaesthetized Wistar rats 2 weeks after acoustic trauma or sham surgery. Electrical stimulation of PFC showed a variety of effects in MGN neurons both in sham and acoustic trauma groups but inhibitory responses were significantly larger in the acoustic trauma animals. These results suggest an alteration in functional connectivity between PFC and MGN after cochlear trauma. This change may be a compensatory mechanism increasing sensory gating after the development of altered spontaneous activity in MGN, to prevent altered activity reaching the cortex and conscious perception.

The mechanism of tinnitus, the perception of sound in the absence of acoustic stimulation, remains as yet unknown. It has been proposed that tinnitus is caused by altered spontaneous activity in the auditory pathway following cochlear damage in combination with inadequate gating at the level of the auditory thalamus, the medial geniculate nucleus (MGN). To investigate this further we made electrophysiological recordings in MGN of guinea pigs (n = 9) with and without tinnitus after acoustic trauma (continuous loud tone at 10 kHz, 124 dB SPL for 2 h). Parameters of interest were spontaneous tonic and burst firing. After acoustic trauma, 5 out of 9 guinea pigs developed signs of tinnitus as determined by the gap prepulse inhibition of acoustic startle. Spontaneous firing rates were significantly increased in the tinnitus animals as compared to the non-tinnitus animals and this change was specific to pure-tone responsive MGN neurons. However, burst firing parameters, including number of bursts per minute, burst duration, number of spikes in each burst, and percentage of spikes occurring in a burst, were not different between tinnitus and non-tinnitus animals. In addition, our data showed a strong dependence of spontaneous firing rates with heart rate, which implies that monitoring physiological status in animals is pertinent to obtaining reliable data when recording at higher levels of the auditory pathway. Our results suggest that increases in the tonic spontaneous fining rate of pure-tone responsive MGN neurons but not changes in burst firing parameters, are a robust neural signature of tinnitus in anaesthetised animals.

visual culture, such as pictographs and petroglyphs can be difficult to interpret and contextualize for the general public, particularly as they hold significant religious or cultural value associated with the peoples who created them. Descendant communities, therefore, can play a prominent and important role in the interpretation, by reinforcing the meaning and significance behind the imagery as part of broader cultural movements or traditions. In New Zealand and Australia, two projects designed and managed by indigenous communities are helping to engage the public not only in an understanding of local and national rock art, but in its continuing conservation. The Te Ana Māori Rock Art Center in Timaru, New Zealand, and the Brambuk Aboriginal Cultural Center in Halls Gap, Australia both rely on the active investment of their respective indigenous communities to promote the wellbeing of heritage material and the continued conversation surrounding its creation. Also addressing issues of racism, colonization, and the forced removal of indigenous populations from their heritage landscapes, the projects interpret the historical material alongside modern ideas and perspectives, helping to initiate connections between the past and present.

Tinnitus is an abnormal phantom perception associated with cochlear trauma, and is thought to cause changes in the rates and patterns of firing neurons in the central auditory pathway. Recent studies have suggested a key role for the auditory thalamus, the medial geniculate nucleus (MGN), in the generation of tinnitus as it may serve a gating function for information en route to cortex. Dysfunctional gating would lead to abnormal activity reaching cortex and hence inappropriate perception, tinnitus, would occur. In this study we compared spontaneous MGN firing rates and burst firing parameters in Wistar rats with and without behavioural evidence of tinnitus following an acoustic trauma. Data were also compared with animals subjected to sham surgery and at an early time-point (2 weeks) after acoustic trauma. Acoustic trauma resulted in a temporary but not a permanent threshold loss and no differences were found in spontaneous firing rate between any of the groups. However, acoustic trauma, whether resulting in tinnitus or not, was accompanied by a significant decrease in the percentage of neurons showing burst firing. In bursting neurons, the number of spikes occurring in a burst and the number of burst per minutes was also significantly reduced compared to the sham group. Our results show that in our rat model without permanent threshold loss, elevated spontaneous firing rates are not associated with acoustic trauma and/or tinnitus and that burst firing parameters are associated with acoustic trauma but are not a neural signature for tinnitus.

Dysfunctional sensory gating has been proposed to result in the generation of phantom perceptions. In agreement, it has been recently suggested that tinnitus, a phantom perception of sound commonly associated with hearing loss, is the result of a breakdown of circuitry involving the limbic system and the medial geniculate nucleus (MGN) of the thalamus. In humans with tinnitus, structural changes and abnormal activity have been found to occur in the auditory pathway as well as parts of the limbic system such as the nucleus accumbens (NAc). However, at present, no studies have been conducted on the influence of the NAc on the MGN. We investigated the functional connectivity between the NAc and MGN single neurons. Bipolar electrical stimulation was delivered to the NAc while recording single neuron activity in MGN in anesthetized Wistar rats. Histological analysis was used to confirm placement of electrodes. NAc electrical stimulation generally decreased spontaneous firing rates in MGN neurons and, in a limited number of neurons, caused an increase in firing rate. This suggests that NAc can modulate the activity of auditory neurons in the MGN and may play a role in the development of tinnitus.

Phantom perceptions have been proposed to arise due to dysfunctional sensory gating at the level of the thalamus. Recently, it has been suggested that tinnitus, a phantom perception of sound, may arise from altered cortico-limbic circuitry and its connection with the auditory thalamus, the medial geniculate nucleus (MGN). Indeed, some elements of this cortico-limbic circuitry, such as the prefrontal cortex (PFC), as well as elements of the auditory pathway, have been shown to be altered in humans with tinnitus. However, the functional connectivity between PFC and MGN has not yet been explored. We therefore investigated the effects of activation of the PFC on neuronal activity in MGN in normal anaesthetized Wistar rats. Bipolar electrical stimulation was delivered to the PFC while recording single neuron activity in the MGN. The majority (81%) of MGN neurons sampled showed a change in their spontaneous firing rate in response to electrical stimulation of the PFC. The effects observed varied greatly between neurons and included combinations of inhibitory and excitatory effects with a wide range of latencies. The effects were not dependent on acoustic response type or MGN subdivision. These data demonstrate that PFC activation can modulate MGN neuronal activity and this connection could potentially play a role in sensory gating of auditory signals.

Architectural collections or reconstructed villages are popular tourist attractions in Europe and the United States, often promoting architecture as a demonstration of national and regional heritages. At times, these sites betray the biases of their creators, perpetuated through methods of display and their public interpretation. The architecture can be used as artifact or backdrop to promote ethics, history, or industry at the hand of curators, particularly when removed from its original context and constructed in a new one. When viewed through the lens of tourism, the collections become a constructed landscape of architectural heritage, experienced by visitors through a narrow understanding of time and place, propagated by fabricated historical connections or purposeful nationalist arrangements. Often accessorizing ‘authentic’ architectural heritage with reconstructions and reproductions, these collections suggest a skewed heritage landscape to the non-specialized visitor, emphasizing tourism over truth and entertainment over education. Following 19th century examples in Scandinavia and the broader introduction of international architecture through the 1893 World’s Columbian Exposition, early 20th century American collections at Greenfield Village and the Manitou Cliff Dwellings underscore the intent to capitalize on architectural heritage tourism, and how a diluted history is interpreted through the eyes of the modern tourist.

The Columbus Indiana Augmented Reality Project is a student-driven initiative to research, interpret, and reproduce the historic urban architecture and landscape of Columbus, Indiana. Focusing initially on the 7 Landmark Buildings housed in the city, the project uses primary source information (original archival drawings photographs, letters, and audio material) to create an enhanced digital model, which patrons can use through an application and web platform to navigate the city either on-site or remotely. Employing the Ball State University approach to entrepreneurial learning, as students learn techniques for creating the environment, they then teach their peers and the public about the information, thus introducing and then reinforcing learning objectives and skillsets. The project provides real world experience in cutting-edge heritage preservation issues and methods, giving students an immersive experience, working with professionals in the field, and creating an immersive digital model to help the public engage with important modernist architecture.

In the formative years of their education, beginning design students are often equipped with several predetermined biases and stereotypical notions about architecture, with specific design intentions centered around how architecture should look, rather than how it should perform. The intent of this paper is to dispel these preconceptions by addressing the iterative design process through conceptual parameters of pattern and module creation, population, and manipulation in an effort to provide students with an alternative perspective for how architecture can create a dialogue with its environment and facilitate the transition from “thing seeing” to “pattern seeing.” In two projects examined in this paper, students were asked to initiate the design process by exploring and testing the inherent strengths and constraints of pattern formations through the lens of a scape and constructed assembly, each of which would focus on principles of ambiance and spatial qualities, rather than relying on traditional architectural typologies. By developing these conceptual projects, students were able to break away from their preconceptions of what architecture is, and instead focus on what architecture could be with a reinvention of the design process.

Cochlear trauma causes increased spontaneous activity (hyperactivity) to develop in central auditory structures, and this has been suggested as a neural substrate for tinnitus. Using a guinea pig model we have previously demonstrated that for some time after cochlear trauma, central hyperactivity is dependent on peripheral afferent drive and only later becomes generated intrinsically within central structures. Furosemide, a loop diuretic, reduces spontaneous firing of auditory afferents. We investigated in our guinea pig model the efficacy of furosemide in reducing 1) spontaneous firing of auditory afferents, using the spectrum of neural noise (SNN) from round window recording, 2) hyperactivity in inferior colliculus, using extracellular single neuron recordings and 3) tinnitus at early time-points after cochlear trauma. Tinnitus was assessed using gap prepulse inhibition of acoustic startle (GPIAS). Intraperitoneal furosemide, but not saline, caused a marked decrease in both SNN and central hyperactivity. Intracochlear perfusion with furosemide similarly reversed central hyperactivity. In animals in which GPIAS measurements suggested the presence of tinnitus (reduced GPIAS), this could be reversed with an intraperitoneal injection with furosemide but not saline. The results are consistent with furosemide reducing central hyperactivity and behavioural signs of tinnitus by acting peripherally to decrease spontaneous firing of auditory afferents. The data support the notion that hyperactivity may be involved in the generation of tinnitus and further suggest that there may be a therapeutic window after cochlear trauma using drug treatments that target peripheral spontaneous activity.

La Arquitectura actúa como la personificación visual de la cultura en el turismo patrimonial, sugiriendo una historia narrativa de “lugar”. En Chichén Itzá los temas sobre comercialización y desarrollo han eclipsado en ocasiones esta narrativa cultural en lugar de volverse ellos mismos aspectos centrales para comprender el complejo arquitectónico como un moderno sitio de la identidad maya en el Yucatán. Desde los orígenes del turismo en masa en el área en los años 70 y enormemente afectado por la creciente industria turística, el lugar ha visto llegar a turistas de todo el mundo para experimentar los restos arqueológicos por motivos religiosos, espirituales, educativos y de ocio. Sin embargo y pese a esta fama, la interpretación de Chichén Itzá es representativa de un número de temas comúnmente asociados a la presentación de lugares arqueológicos particularmente la introducción del turismo en masa y el cambio hacia la comercialización y accesibilidad del sitio a expensas del patrimonio maya local. A pesar de estas significativas preocupaciones, el complejo de Chichén Itzá puede ser interpretado como representativo tanto de las antiguas como de las modernas poblaciones mayas a través de la participación activa de los residentes locales mayas en la gestión arqueológica del sitio y a través de la conexión teológica de la interpretación de las prácticas culturales de los antiguos maya. La interpretación patrimonial ejemplifica un discurso en creciente desarrollo y crecientemente multidimensionado, donde las prácticas que están surgiendo son investigadas, permitiendo un gradiente de prácticas “exitosas” que son juzgadas utilizando diversos criterios. De forma paralela a la antigua estructura e historia políticas mayas y bajo estos criterios emergentes, la interpretación del sitio puede ser contada a través de las conexiones históricas mayas, poniendo el acento sobre la investigación del pasado para buscar pistas y acomodando las cambiantes necesidades en arquitectura.