People
George Souza, PhD
 | Assistant Professor |
Areas of Expertise
- General: Cardiovascular and Respiratory Neurobiology; Integrative neuroscience
- Specific: Neural control of blood pressure and cerebral perfusion; Central and peripheral respiratory chemoreception; Autonomic and respiratory function during sleep-wake cycle and other brain states.
Research Methods
Our laboratory utilizes calcium imaging via fiber photometry to analyze the activity of neuronal groups in conscious rodents (mice and rats). To study the gain- or loss-of-function of a given neuronal group for breathing or blood pressure homeostasis, we utilize neuronal manipulation via optogenetics or genetically-targeted neuronal ablation. These approaches often involve transgenic rodent lines (Cre-driver strains) and stereotaxic microinjections of viral vectors encoding opsins or calcium indicators. We frequently record multiple physiological parameters simultaneously, including blood pressure, respiration, EEG/EMG activity, cerebral blood flow, and sympathetic nerve activity.
Current Projects
Sympathetic mechanisms of cerebral blood flow regulation
Research Summary
Distinct neuronal groups located at the ventral brainstem determine the CO2/pHdrive to breath and the sympathetic tone that regulates arterial blood pressure, serving as key components of the chemo- and baroreflex neural circuits, respectively. Our research focuses on understanding how these two different classes of neurons maintain respiratory and cardiovascular homeostasis, with particular emphasis on the regulation of cerebral blood flow and brain oxygenation. For this, we record and manipulate the activity of these neurons in rodents during natural behaviors—such as sleep-wake cycles and postural changes—as well as in models of elevated intracranial pressure, heart failure and other pathophysiological conditions that challenge homeostasis. By elucidating the neural mechanisms underlying cardiorespiratory control and cerebral perfusion, we seek to clarify the mechanisms of disease and lay the groundwork for developing targeted therapies for cardiovascular, respiratory, and cerebrovascular disorders.