edward l. bartlett ph.d., university of wisconsin –auditory thalamus in vitro synaptic physiology...

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

ICIC

MGBMGB

Aud. Aud. CortexCortex

Adapted from NetterAdapted from Netter

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 sound feature extractionextraction

Perception, Perception, Decision, Decision,

ActionAction

SoundSound

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

Recent ResultsNeural representation of temporal

modulation

- synchronized vs non-synchronized

- temporally vs spectrally specialized pathways

Correlation with MGB subdivision

Synchronized Synchronized TemporalTemporalrepresentation,representation,MGVMGV

Non-SynchronizedNon-Synchronized Rate Rate representation, representation, MGCDMGCD

40 Hz click train40 Hz click train

250 Hz click train250 Hz click train

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

Auditorythalamus

Cooling probe

Single neuron responseSingle neuron response

Adapted from Castro-Alamancos, 2004Adapted from Castro-Alamancos, 2004