1. Edward L. Bartlett Ph.D., University of Wisconsin –Auditory thalamus in vitro synaptic physiology and anatomy Postdoctoral Research at Johns Hopkins University –Auditory cortex and thalamus neuronal recordings in vivo Assistant Professor, Departments of Biological Sciences and Biomedical Engineering –Functional organization of auditory cortex and thalamus in vivo and in vitro IC MGB Aud. Cortex Adapted from Netter

2. Current Research Areas Neural representation of sound features in auditory thalamus and cortex – –Sound sequences – –Neural coding of temporal modulation – –Neural coding of sound frequency, level Neuroanatomy – –Calcium-binding proteins – –Correlation with neurophysiology Animal Models: – –Marmoset monkey (at JHU) – –Rodent (at Purdue) Cochlea AN CN SOC/LL IC Aud. Thalamus Aud. Cortex sound feature extraction Perception, Decision, Action Sound

3. Methodologies Single-neuron extracellular recording -awake animals Sound and electrical stimulation Neuroanatomy Intracellular recording in brain slices -synaptics, dynamic clamp Modeling of neurons and circuits

4. Recent Results Neural representation of temporal modulation - synchronized vs non- synchronized - temporally vs spectrally specialized pathways Correlation with MGB subdivision Synchronized Temporal representation, MGV Non-SynchronizedRaterepresentation,MGCD 40 Hz click train 250 Hz click train

5. Future Directions Auditory responses in thalamus and cortex: normal and aged animals Corticothalamic feedback modulation Representation of complex sounds (two sources, sounds in noise, behaviorally relevant sounds) Cellular mechanisms of in vivo responses Auditory cortex Auditory thalamus Cooling probe Single neuron response Adapted from Castro-Alamancos, 2004