The Physiological and Behavioral
Neuroscience in Juveniles Lab headed by Dr. Theodore Dumas at the Krasnow
Institute aims to uncover brain mechanisms involved in learning and
memory. We focus on hippocampal-dependent
processes in mice at the end of the third postnatal week, which is comparable
to 2-4 years old in humans. As an OSCAR
rehire in Dr. Dumas’s lab, I have enjoyed opportunities to experience various
branches of neuroscience research and I have developed skills that prepare me
for a successful future in neuroscience.
The project I currently work on utilizes
various electrophysiological measures testing for neuroplasticity—long lasting
functional changes due to experience—implicated in learning and memory. Two molecular mechanisms found to play a
substantial role in plasticity are NMDA and AMPA receptors that bind to glutamate,
the brains main “excitatory” neurotransmitter. When NMDA channels open, they allow calcium to
flow into the post-synaptic cell; this causes depolarization and leads to
long-term changes. This means that NMDA
receptors have a certain amount of control over information processing and form
pathways that activate easier according to environmental stimulus. Thus, we use transgenic mice with separate
domains of NMDA receptors in order to regulate different aspects of spatial
cognition distinctive in the hippocampus.
Electrophysiology allows me to test
plasticity in hippocampal neurons of adult vs. adolescent chimeric mice and
compare responses to delineate specific mechanisms and their effect on learning
and memory. To obtain the necessary information,
I meticulously place a tiny stimulating electrode on the axons of Schaffer
collateral cells (pre-synaptic) in a slice of mouse hippocampus—the neurons are
kept alive using artificial cerebral spinal fluid—that delivers a stimulus voltage
to trigger depolarization via glutamate receptors. A second hollow recording microelectrode is
placed carefully at the cell bodies of CA1 (post-synaptic) cells and records
the post-synaptic electrical response. I
also measure responses in “silenced” neurons encoded with fly allatostatin
receptors. When activated, these
receptors keep the cell in a hyperpolarized state, thereby blocking all
on-going activity. This provides data
relating specific neurons to aspects of hippocampal-dependent learning and
memory function. A majority of my time
is spent analyzing the data from the abovementioned tests and making
correlations relevant to the goals of our lab.
