Abstract
Cocultures of the learning-relevant forebrain
region mediorostrai neostriatum and
hyperstriatum ventrale (MNH) and its main
glutamatergic input area nucleus dorsomedialis
anterior thalami/posterior thalami were morphologically
and physiologically characterized.
Synaptic contacts of thalamic fibers were lightand
electron-microscopically detected on MNH
neurons by applying the fluorescence tracer
DiI-C18(3) into the thalamus part of the coculture.
Most thalamic synapses on MNH neurons
were symmetric and located on dendritic shafts,
but no correlation between Gray-type ultrastructure
and dendritic localization was found.
Using intraceilular current clamp recordings, we
found that the electrophysiological properties,
such as input resistance, time constant, action
potential threshold, amplitude, and duration of
MNH neurons, remain stable for over 30 days in
vitro. Pharmacological blockade experiments
revealed glutamate as the main neurotransmitter
of thalamic synapses on MNH neurons, which
were also found on inhibitory neurons. High
frequency stimulation of thalamic inputs evoked
synaptic potentiation in