The sites of action of lidocaine on the responses evoked by stimulation of lateral column (LC) and dorsal root (DR) were studied in the isolated, intra-arterially perfused spinal cord of the bullfrog. When the ventral root volley produced by stimulation was abolished by lidocaine, the presynaptic focal potential was almost unchanged. Intracellular recordings from motoneurons clearly demonstrate...

Monosynaptic connections to dorsal neck motoneurons of the cat from single afferents supplying primary endings of neck muscle spindles were studied using spike-triggered averaging techniques. Single-fiber EPSPs were detected in only 11 of the 112 afferent-motoneuron pairs examined. The average amplitude of single-fiber EPSPs recorded in motoneurons with a membrane potential of greater than -40 ...

The perforant path forms a monosynaptic connection between the cells of layer II of the entorhinal cortex and the pyramidal cells in hippocampal area CA3. Although this projection is prominent anatomically, very little is known about the physiological properties of this input. The distal location of these synapses suggests that somatically recorded perforant-path excitatory postsynaptic potenti...

The temporal precision with which EPSPs initiate action potentials in postsynaptic cells determines how activity spreads in neuronal networks. We found that small EPSPs evoked from just subthreshold potentials initiated firing with short latencies in most CA1 hippocampal inhibitory cells, while action potential timing in pyramidal cells was more variable due to plateau potentials that amplified...

We investigated the role of A-type K(+) channels for the induction of long-term potentiation (LTP) of Schaffer collateral inputs to hippocampal CA1 pyramidal neurons. When low-amplitude excitatory postsynaptic potentials (EPSPs) were paired with two postsynaptic action potentials in a theta-burst pattern, N-methyl-d-aspartate (NMDA)-receptor-dependent LTP was induced. The amplitudes of the back...

Experience-dependent plasticity in somatosensory (S1) and visual (V1) cortex involves rapid depression of responses to a deprived sensory input (a closed eye or a trimmed whisker). Such depression occurs first in layer II/III and may reflect plasticity at vertical inputs from layer IV to layer II/III pyramids. Here, I describe a timing-based, associative form of long-term potentiation and depre...

Concerns about genetically modified (GM) crops include transgene flow to compatible wild species and unintended ecological consequences of potential transgene introgression. However, there has been little empirical documentation of establishment and distribution of transgenic plants in wild populations. We present herein the first evidence for escape of transgenes into wild plant populations wi...

The synaptic pathways of mesencephalic locomotor region (MLR)-evoked excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) recorded from lumbar motoneurons of unanesthetized decerebrate cats during fictive locomotion were analyzed prior to, during, and after cold block of the medial reticular formation (MedRF) or the low thoracic ventral funiculus (VF). As others have shown, elect...

The brain stem provides most of the noradrenaline (NA) present in the spinal cord, which functions to both increase spinal motoneuron excitability and inhibit sensory afferent transmission to motoneurons (excitatory postsynaptic potentials; EPSPs). NA increases motoneuron excitability by facilitating calcium-mediated persistent inward currents (Ca PICs) that are crucial for sustained motoneuron...

In anesthetized cats, single group Ia fibers were activated with a train of 52 stimuli whose interspike intervals were obtained from the discharge of a group Ia fiber in a walking cat (courtesy of Dr. G. E. Loeb, NIH). The EPSPs recorded in motoneurons to which the afferents projected were averaged in register (EPSP1, EPSP2, ..., EPSP52) in response to multiple presentations of the train at a r...