| The study of neuronal activity in awake and freely moving animals represents a chance to examine neuronal function during natural behavior without the stress and suppression of activity inherent in the use of anesthetics and physical restraints. Functional magnetic resonance imaging and positron emission tomography allow three-dimensional recording of brain metabolism, but these techniques are indirect measures of neuronal activity, have low temporal and spatial resolution and require head fixation. Conversely, implantable micro-electrode arrays allow high speed recording of neuronal activity in awake, unrestrained, and mobile animals. While these electrophysiologic methods have produced profound insights into neurophysiological events associated with sensory activation, motor tasks, sensory motor integration and cognitive processes, these methods can only monitor a few dozen neurons simultaneously in an awake, behaving animal.;Voltage-sensitive optical probes can provide high spatial and temporal resolution, while being less invasive than traditional micro-electrode methods. Scientific image sensors tailored for optical probes exist, but they are designed for fixed-animal experiments and are not suitable for behaving animals. Thus, a miniature camera, built around a custom-designed image sensor, is required to record neuronal activity in rodents with optical probes.;This thesis reports various CMOS image sensors specifically designed for a head-mountable imaging system for rodents. A small, self-contained imaging system with high sensitivity (> 50 dB), speed (> 300 frames/sec) and large field of view (> 2 mm2) is presented. The system consumes under 100 mW of power and does not require active cooling. This work represents a first generation, mobile scientific-grade, physiology imaging camera. |
