The spatiotemporal dynamics of autobiographical memory: neural correlates of recall, emotional intensity, and reliving.

We sought to map the time course of autobiographical memory retrieval, including brain regions that mediate phenomenological experiences of reliving and emotional intensity. Participants recalled personal memories to auditory word cues during event-related functional magnetic resonance imaging (fMRI). Participants pressed a button when a memory was accessed, maintained and elaborated the memory, and then gave subjective ratings of emotion and reliving. A novel fMRI approach based on timing differences capitalized on the protracted reconstructive process of autobiographical memory to segregate brain areas contributing to initial access and later elaboration and maintenance of episodic memories. The initial period engaged hippocampal, retrosplenial, and medial and right prefrontal activity, whereas the later period recruited visual, precuneus, and left prefrontal activity. Emotional intensity ratings were correlated with activity in several regions, including the amygdala and the hippocampus during the initial period. Reliving ratings were correlated with activity in visual cortex and ventromedial and inferior prefrontal regions during the later period. Frontopolar cortex was the only brain region sensitive to emotional intensity across both periods. Results were confirmed by time-locked averages of the fMRI signal. The findings indicate dynamic recruitment of emotion-, memory-, and sensory-related brain regions during remembering and their dissociable contributions to phenomenological features of the memories.

Shaping Religious and Cultural Aspiration: Engraved Sutras in Southwestern Shandong Province from the Northern Qi Dynasty (550-577 CE), China

This dissertation explores how the Buddhist texts carved on the cliffs of mountains served their patrons’ religious and cultural goals. During the Northern Qi period (550-577 CE), these carved Buddhist sutra texts and Buddha names were prevalent, and were carved directly onto the surfaces of numerous mountains in southwestern Shandong Province. The special focus of this study is on the Buddhist engravings at Mt. Hongding in Dongping, and at Mt. Tie in Zoucheng. Created in approximately 553-564 CE, the carvings at Mt. Hongding stand as the terminus a quo of the history of Buddhist sutras carved into the rocks of the Shandong mountains. The Buddhist carvings at Mt. Hongding served monastic goals. The monk patrons, Seng’an Daoyi, Fahong, and others created the carvings as an integral part of their Buddhist meditation practices. The carvings at Mt. Tie paint a very different picture. At Mt. Tie, a colossal Buddhist sculpture-style carving was created in 579 CE. Sponsored by several Han Chinese patrons, the carving was designed in the form of a gigantic Chinese traditional stele. This study suggests that several Han Chinese local elites proudly displayed their Han Chinese linage by using the gigantic stele form of Buddhist text carving as a means to proclaim Han Chinese cultural and artistic magnificence. To achieve these non-religious goals, they appropriated rhetorical devices often used by the Han elite, such as the stele form, written statements about the excellence of the calligraphy used, and discourse on calligraphy connoisseurship.

Spatiotemporal Dynamics of CaMKI During Structural Plasticity of Single Dendritic Spines

Multifunctional calcium/calmodulin dependent protein kinases (CaMKs) are key regulators of spine structural plasticity and long-term potentiation (LTP) in neurons. CaMKs have promiscuous and overlapping substrate recognition motifs, and are distinguished in their regulatory role based on differences in the spatiotemporal dynamics of activity. While the function and activity of CaMKII in synaptic plasticity has been extensively studied, that of CaMKI, another major class of CaMK required for LTP, still remain elusive.

Here, we develop a Förster’s Resonance Energy Transfer (FRET) based sensor to measure the spatiotemporal activity dynamics of CaMK1. We monitored CaMKI activity using 2-photon fluorescence lifetime imaging, while inducing LTP in single dendritic spines of rat (Rattus Norvegicus, strain Sprague Dawley) hippocampal CA1 pyramidal neurons using 2-photon glutamate uncaging. Using RNA-interference and pharmacological means, we also characterize the role of CaMKI during spine structural plasticity.

We found that CaMKI was rapidly and transiently activated with a rise time of ~0.3 s and decay time of ~1 s in response to each uncaging pulse. Activity of CaMKI spread out of the spine. Phosphorylation of CaMKI by CaMKK was required for this spreading and for the initial phase of structural LTP. Combined with previous data showing that CaMKII is restricted to the stimulated spine and required for long-term maintenance of structural LTP, these results suggest that CaMK diversity allows the same incoming signal – calcium – to independently regulate distinct phases of LTP by activating different CaMKs with distinct spatiotemporal dynamics.

The Didache and Traditioned Innovation: Shaping Christian Community in the First Century and the Twenty-First Century

Church leaders, both lay and clergy, shape Christian community. Among their central tasks are: building communal identity, nurturing Christian practices, and developing faithful structures. When it comes to understanding the approach of the earliest Christian communities to these tasks, the Didache might well be the most important text most twenty-first century church leaders have never read. The Didache innovated on tradition, shaping the second generation of Christians to meet the crises and challenges of a changing world.

Most likely composed in the second half of the first century, the Didache served as a training manual for gentile converts to Christianity, preparing them for life in Christian community. This brief document, roughly one third the length of Mark’s gospel, developed within early Jewish-Christian communities. It soon found wide usage throughout the Mediterranean region, and its influence endured throughout the patristic and into the medieval period.

The Didache outlines emerging Christian practices that were rooted in both Jewish tradition and early Jesus material, yet were reaching forward in innovative ways. The Didache adopts historical teachings and practices and then adapts them for an evolving context. In this respect, the writers of the Didache, as well as the community shaped by its message, exemplify the pattern of thinking described by Greg Jones as “traditioned innovation.”

The Didache invites reflection on the shape and content of Christian community and Christian leadership in the twenty-first century. As churches and church leaders engage a rapidly changing world, the Didache is an unlikely and yet important conversation partner from two millennia ago. A quick read through its pages – a task accomplished in less than half an hour – brings the reader face to face with a brand of Christianity both very familiar and strikingly dissimilar to modern Christianity. Such dissonance challenges current assumptions about the church and creates a space in which to re-imagine our situation in light of this ancient Christian tradition. The Didache provides a window through which we might re-examine current conceptualizations of Christian life, liturgy, and leadership.

This thesis begins with an exploration of the form and function of the Didache and an examination of a number of important background issues for the informed study of the Didache. The central chapters of this thesis exegete and explore select passages in each of the three primary sections of the Didache – the Two Ways (Didache 1-6), the liturgical section (Didache 7-10), and the church order (Didache 11-15). In each instance, the composers of the Didache reach back into a cherished and life-giving aspect of the community’s heritage and shape it anew into a fresh and faithful approach to living the Christian life in a drastically different context.

The thesis concludes with three suggestions of how the Didache may provide a resource for the way the Church in the present thinks about training disciples, shaping community, and developing leadership structures. These conversation starters offer beginning points for a richer, fuller discussion of traditioned innovation in our current church context. The Didache provides a source of wisdom from our spiritual forebears that modern Christian leaders would do well not to ignore. With a look through the first century window of the Didache, twenty-first century Christians can discover fresh insights for shaping Christian community in the present.