Institutions and Economic Growth: How Institutional Change Triggers Divergence, Convergence, and Non-Zero Sums

The thesis explores the effect of institutional change on economic output. Chapters 1 and 2 are empirical and examine historical events. Chapter 1 makes the case that the Mongol Empire played a prominent role in the Industrial Revolution emerging in Western Europe. Western Europe developed democratic institutions that better supported economic growth because it was never successfully invaded by the Mongols. Chapter 2 uses the collapse of the USSR as a natural experiment and shows that the countries born from the collapse of the USSR that opted to join the European Union did better than the countries that did not. The paper makes the case that this was due to the market-focused institutions of the EU. Chapter 3 is a theoretical paper that develops a model elucidating the primary causes of the sudden jump in growth rates concurrent with the Industrial Revolution using game theory. The idea is that good institutions shift the payoffs to engaging in cooperative endeavors such as trade

A Review of Transcranial Magnetic Stimulation and Multimodal Neuroimaging to Characterize Post-Stroke Neuroplasticity

Following stroke, the brain undergoes various stages of recovery where the central nervous system can reorganize neural circuitry (neuroplasticity) both spontaneously and with the aid of behavioral rehabilitation and non-invasive brain stimulation. Multiple neuroimaging techniques can characterize common structural and functional stroke-related deficits, and importantly, help predict recovery of function. Diffusion tensor imaging (DTI) typically reveals increased overall diffusivity throughout the brain following stroke, and is capable of indexing the extent of white matter damage. Magnetic resonance spectroscopy (MRS) provides an index of metabolic changes in surviving neural tissue after stroke, serving as a marker of brain function. The neural correlates of altered brain activity after stroke have been demonstrated by abnormal activation of sensorimotor cortices during task performance, and at rest, using functional magnetic resonance imaging (fMRI). Electroencephalography (EEG) has been used to characterize motor dysfunction in terms of increased cortical amplitude in the sensorimotor regions when performing upper limb movement, indicating abnormally increased cognitive effort and planning in individuals with stroke. Transcranial magnetic stimulation (TMS) work reveals changes in ipsilesional and contralesional cortical excitability in the sensorimotor cortices. The severity of motor deficits indexed using TMS has been linked to the magnitude of activity imbalance between the sensorimotor cortices. In this paper, we will provide a narrative review of data from studies utilizing DTI, MRS, fMRI, EEG, and brain stimulation techniques focusing on TMS and its combination with uni- and multimodal neuroimaging methods to assess recovery after stroke. Approaches that delineate the best measures with which to predict or positively alter outcomes will be highlighted

Sensorimotor Experience Influences Recovery of Forelimb Abilities but Not Tissue Loss after Focal Cortical Compression in Adult Rats

Sensorimotor activity has been shown to play a key role in functional outcome after extensive brain damage. This study was aimed at assessing the influence of sensorimotor experience through subject-environment interactions on the time course of both lesion and gliosis volumes as well as on the recovery of forelimb sensorimotor abilities following focal cortical injury. The lesion consisted of a cortical compression targeting the forepaw representational area within the primary somatosensory cortex of adult rats. After the cortical lesion, rats were randomly subjected to various postlesion conditions: unilateral C5–C6 dorsal root transection depriving the contralateral cortex from forepaw somatosensory inputs, standard housing or an enriched environment promoting sensorimotor experience and social interactions. Behavioral tests were used to assess forelimb placement during locomotion, forelimb-use asymmetry, and forepaw tactile sensitivity. For each group, the time course of tissue loss was described and the gliosis volume over the first postoperative month was evaluated using an unbiased stereological method. Consistent with previous studies, recovery of behavioral abilities was found to depend on post-injury experience. Indeed, increased sensorimotor activity initiated early in an enriched environment induced a rapid and more complete behavioral recovery compared with standard housing. In contrast, severe deprivation of peripheral sensory inputs led to a delayed and only partial sensorimotor recovery. The dorsal rhizotomy was found to increase the perilesional gliosis in comparison to standard or enriched environments. These findings provide further evidence that early sensory experience has a beneficial influence on the onset and time course of functional recovery after focal brain injury

The origins of liberal democracy and the economic legacy of the Mongol empire

I explore the fact that the Mongol Empire invaded most of Eurasia but left Western Europe untouched. I hypothesize that differences in exposure to the Mongols resulted in divergent institutional paths. Where the Mongols invaded, they set up highly centralized autocratic institutions. Meanwhile, Western Europe developed comparatively more liberal and decentralized institutions. I suggest that these differences in institutions have persisted until the present day. Using the legacy of Mongol invasions as a factor in the rise of existing institutions as an instrument for current institutions, I find significant effects on current GDP/capita caused by these divergent institutional paths