Neurophysiology Laboratory of Kimberle M. Jacobs

Kimberle M. Jacobs, PhD

PhD 1994 Neuroscience, 
Brown University

Associate Professor
Anatomy & Neurobiology
Virginia Commonwealth University
Richmond, VA 23298

Spontaneous GABA_A inhibitory currents recorded from a layer V pyramidal neurons.

Averaged spontaneous inhibitory currents from layer V pyramidal neurons in normal (blue) and epileptogenic (white) neocortex.

Evoked inhibitory currents with epileptogenic-like activity (arrows).

Layer V neocortical pyramidal neuron filled with biocytin during patch clamp recordings.

Containing billions of neurons and trillions of synaptic connections, the cerebral cortex may well be the defining feature of the mammalian brain.  Responsible for consciousness, perception, abstract thought, memory, planning, and language, the neocortex is what makes us human.  This is also evident in the evolutionary expansion of brain volume devoted to neocortex.  One of the most elegant features of the neocortex is its modular design, consisting of repetitive elements whose function depends on input.  These components are defined during development by successive stages of neuron birth, migration, differentiation, and synaptic connection. The intricate connections between elements are shaped during development with environmental influences.  The incredible facility of the neocortex for adaptation based on experience, learning, and maldevelopment has become far more evident in the last twenty years.

One current challenge is to identify which neuronal processes are plastic at each developmental stage and how these processes are affected by common clinical maladies.  Brain damage during development can result from a variety of insults, such as  maternal infections, direct trauma, vascular infarction, genetic abnormalities, and exposure to toxins, including alcohol and drugs.  These developmental perturbations will produce varying effects, depending on timing, severity, and location.  Disruption in the balance between excitation and inhibition, producing seizures is a common result from any of these insults, often accompanying other symptoms such as dyslexia, mental retardation, and schizophrenia.  Local changes in excitation and inhibitory balance allow for desired forms of plasticity, such as those required during learning.  One goal is to understand the modulators that permit the shift between local fluctuations and more globally synchronized and detrimental imbalances of excitation and inhibition.

Despite the overall complexity of connections, individual cell types and circuits responsible for particular neuronal behaviors can be identified.  My principal interest is in identifying the cellular components and mechanisms that allow for and produce specific forms of cortical plasticity.

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