Andreas Burkhalter, PhD
Professor, Anatomy & Neurobiology
School of Medicine
Campus Box 8108
North Building, 4400
St. Louis, MO 63110
Our studies of the visual system in mice are aimed at understanding how the visual cortex is subdivided into different areas, how the network of connections between areas develops, how it is organized in the adult and how it is altered by visual experience. Interareal networks are important for visual perception and visually guided actions. The work is focused on identifying cortical areas, defining their hierarchical relationships and studying the circuits that connect lower with higher visual areas. These circuits are formed by feedforward and feedback connections that are composed of excitatory and inhibitory neurons. The goal is to understand how during development the strengths of excitatory and inhibitory synaptic connections are adjusted to generate unique circuit-specific balances of excitation and inhibition.
We are employing a combination of anatomical and physiological techniques. For delineating area maps we are using axonal tracing of connections and extracellular recording of receptive fields to map the topographic organization of visual cortex. To study the structure of synapses and identify their postsynaptic targets we are using neuronal tracers and cell-type specific markers of excitatory and inhibitory neurons and analyses in the confocal and electron microscopes. For determining the mechanisms of synaptic transmission we are using whole cell recording of GFP labeled inhibitory and excitatory neurons in brains slices. An important focus is to find out how during development inhibition in feedforward and feedback circuits become different and to understand the role of visual experience in this process. The long-term goal of our research is to provide a better understanding of the structure, physiology and plasticity of interareal cortical circuits that provide for the cortical representation of visual information and the ion of parts of the visual image for concentrated attention and interpretation.
- Burkhalter A, Gonchar Y, Mellor RL, Nerbonne JM. Related Articles, Links Differential expression of I(A) channel subunits Kv4.2 and Kv4.3 in mouse visual cortical neurons and synapses. J Neurosci. 2006 Nov 22;26(47):12274-82.
- Wang Q, Gao E, Burkhalter A. Related Articles, Links In vivo transcranial imaging of connections in mouse visual cortex. J Neurosci Methods. 2007 Jan 30;159(2):268-76.
- Yuan W, Burkhalter A, Nerbonne JM. Related Articles, Links Functional role of the fast transient outward K+ current IA in pyramidal neurons in (rat) primary visual cortex. J Neurosci. 2005 Oct 5;25(40):9185-94.
- Dong H, Wang Q, Valkova K, Gonchar Y, Burkhalter A. Related Articles, Links Experience-dependent development of feedforward and feedback circuits between lower and higher areas of mouse visual cortex. Vision Res. 2004 Dec;44(28):3389-400.
- Dong H, Shao Z, Nerbonne JM, Burkhalter A. Related Articles, Links Differential depression of inhibitory synaptic responses in feedforward and feedback circuits between different areas of mouse visual cortex. J Comp Neurol. 2004 Jul 26;475(3):361-73.
- Tychsen L, Wong AM, Burkhalter A. Related Articles, Links Paucity of horizontal connections for binocular vision in V1 of naturally strabismic macaques: Cytochrome oxidase compartment specificity. J Comp Neurol. 2004 Jun 21;474(2):261-75