Foto del docente

Sandra Guidi

Assistant professor

Department of Biomedical and Neuromotor Sciences

Academic discipline: BIO/09 Physiology

Research

Down syndrome

Hippocampus and hippocampal network

Neurogenesis and environment



A first line of research is aimed at detecting the mechanisms underlying brain hypotrophy in Down syndrome (DS), a genetic disease characterized by severe mental retardation. In a transgenic mouse model for DS (the Ts65Dn mouse) and brain samples from fetuses with DS we are investigating alterations in the process of neurogenesis in the subventricular zone (a region that contains the progenitor of neurons that will populate the cerebral cortex), the hippocampus and cerebellum, two structures notably hypotrophic in DS patients. In the mouse model, we are trying to dissect the molecular mechanisms underlying defective neuron formation in DS by using in vivo and in vitro approaches. In an attempt to find effective treatments, possibly useful in humans, we are also focusing on therapies that could enhance neuron production.

A second line of research has the aim of obtaining insight into the neuronal operations that take place in the hippocampal network, with the hope to reveal the contribution of network activity to memory functions. In particular, we are interested in the study of signal transfer along the hippocampal-parahippocampal network, with particular emphasis on the entorhinal cortex-hippocampus-entorhinal cortex loop, a critically relevant circuit for learning and memory. The research involves electrophysiological techniques in the anesthetized guinea pig, with simultaneous multiple recordings of extracellular field potentials and unit activity from the hippocampal fields and entorhinal cortex and analysis of the synaptic function (input-output function, current source density profiles, short- and long- term plasticity) in each structure. Different inputs and input patterns are used to reveal different models of signal transfer, possibly related to different behaviors.

A third line of research is aimed at investigating the long-term effects of early life experiences on the organization of hippocampal circuits essential for the establishment of long-term memories. We investigate, in Guinea pig, the long term effects of early life conditions on the hippocampal circuits with multiple approaches involving electrophysiological, cellular biology and morphometrical techniques. With this converging approaches we hope to ascertain the impact of early life experiences on the synaptic function of hippocampal networks and to identify structural plastic changes (synapse formation, remodeling of dendrites, and neurogenesis) and cellular mechanisms underlying the effects of environment on the hippocampal function.