Discharge Properties of Neurons in Subdivisions of the Medial Geniculate Body
of the Guinea Pig
E. Kvašòák, J. Popeláø, J. Syka
Institute of Experimental Medicine, Academy of Sciences of the Czech
Republic, Prague, Czech Republic
Received August 5, 1999
Accepted January 25, 2000
Summary
The activity of 194 neurons was recorded in three
subdivisions of the medial geniculate body (74 neurons in the ventral, 62 in the
medial and 44 neurons in the dorsal subdivision, i.e. vMGB, mMGB and dMGB) of
guinea pigs anesthetized with ketamine-xylazine. The discharge properties of
neurons were evaluated by means of peristimulus time histograms (PSTHs),
interval histograms (INTHs) and auto-correlograms (ACGs). In the whole MGB, the
most frequent PSTH responses to pure tone stimuli were onset (43 %) or chopper
(32 %). The onset responses were mostly present in the vMGB, whereas chopper
responses dominated in the dMGB. In the whole MGB Poisson-like and bimodal INTHs were found in 46 % and 40 % of neurons, respectively. The mMGB revealed
fewer bimodal and more symmetrical types of INTH. In the whole MGB,
60 % of units were found to have ACGs typical for short
bursts (<100 ms), 23 % for long bursts (>100 ms) and 15 % of units fired
without bursts. Neurons in the vMGB were characterized by short bursting,
whereas those in the mMGB and dMGB expressed more activity in the long bursts.
The results demonstrate that the type of information processing in the vMGB,
which belongs to the ”primary” auditory system, is different from that in
two other subdivisions of the MGB.
Key words
Discharge pattern · Single neuron
activity · Medial geniculate body ·
Subdivisions · Guinea pig
Reprint requests
Mgr. Eugen Kvašòák, Institute of Experimental Medicine,
Academy of Science of the Czech Republic, Vídeòská 1083, 142 20 Prague 4,
Czech Republic.
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