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The lemniscal–cuneate recurrent excitation is suppressed by strychnine and enhanced by GABA A antagonists in the anaesthetized cat
Author(s) -
Aguilar Juan,
Soto Cristina,
Rivadulla Casto,
Canedo Antonio
Publication year - 2002
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2002.02230.x
Subject(s) - strychnine , cuneate nucleus , disinhibition , neuroscience , chemistry , stimulation , excitatory postsynaptic potential , gabaergic , receptive field , inhibitory postsynaptic potential , neurotransmission , glycine receptor , bicuculline , lateral inhibition , interneuron , antagonist , psychology , glycine , receptor , biochemistry , amino acid
In the somatosensory system, cuneolemniscal (CL) cells fire high frequency doublets of spikes facilitating the transmission of sensory information to diencephalic target cells. We studied how lemniscal feedback affects ascending transmission of cutaneous neurons of the middle cuneate nucleus. Electrical stimulation of the contralateral medial lemniscus and of the skin at sites evoking responses with minimal threshold induced recurrent activation of CL cells at a latency of 1–3.5 ms. The lemniscal feedback activation was suppressed by increasing the stimulating intensity at the same sites, suggesting recurrent‐mediated lateral inhibition. The glycine antagonist strychnine blocked the recurrent excitatory responses while GABA A antagonists uncovered those obscured by stronger stimulation. CL cells sharing a common receptive field (RF) potentiate one another by recurrent activation and disinhibition, the disinhibition being produced by serial interactions between glycinergic and GABAergic interneurons. Conversely, CL cells with different RFs inhibit each other through recurrent GABA‐mediated inhibition. The lemniscal feedback would thus enhance the surround antagonism of a centre response by increasing the spatial resolution and the transmission of weak signals.