Welcome to the Constantinidis laboratory. Research in the lab centers around the neurophysiology of cognitive functions. Ongoing projects examine the role of dorsolateral prefrontal and posterior parietal cortex in processes such as working memory, learning, and selective attention. Cortical circuit analysis Simultaneous cortical recordings from arrays of microelectrodes allow us to monitor the activity of multiple neurons at a time and to infer their patterns of connectivity using cross-correlation analysis. 
Neuronal cell types (pyramidal vs. non-pyramidal) can be resolved based on the action potential waveform and discharge rate characteristics of neurons recorded. 
The patterns of effective connectivity between neurons and the flow of information between them can then be determined. 
Effects of learning and memory Ongoing experiments in the laboratory are addressing how experience and learning affect the physiological properties of individual cortical neurons, as well as their patterns of connectivity. Experiments monitor the spiking activity of multiple neurons, as well as population of neurons via local-field-potential recordings. Recent recordings from the posterior parietal cortex of monkeys either required to simply fixate (naïve) or to perform a delayed-match-to-sample task (trained) suggest that parietal neurons automatically encode salient stimuli, even when those have no behavioral significance for the animals. However, training does alter the physiological properties of neurons, by quantitatively enhancing the discriminative power of stimuli. 
Computational analysis and modeling Results of our neurophysiological experiments are used for computational analysis and modeling. 
Computer simulations can investigate the patterns of interactions between neurons and provide insight on the functions of the cortical circuits. Specialization of higher cortical areas Virtually all cognitive functions generate activation of a large network of cortical areas. The unique roles and cooperative interactions of these areas have only recently begun to be investigated. We are currently focusing on the posterior parietal and prefrontal cortices, two interconnected brain regions, which are involved in the processing of visual, spatial information. 
Experiments seek to understand how a) the physiological properties of neurons in the two areas differ during execution of a variety of cognitive tasks that involve visual-spatial processing; b) what underlying circuit specializations mediate the functional specificity of the two areas; c) what the functional implications of such circuit differences are. |