Roddy Williamson

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Cephalopods have arguably the largest and most complex nervous systems amongst the invertebrates; but despite the squid giant axon being one of the best studied nerve cells in neuroscience, and the availability of superb information on the morphology of some cephalopod brains, there is surprisingly little known about the operation of the neural networks(More)
Intracellular recordings were made from primary sensory hair cells located on the dorsal side of the anterior crista segment of the squid statocyst. These hair cells were electrophysiologically identified by the occurrence of an antidromic action potential after electrical stimulation of the crista nerve. Two types of subthreshold, depolarising potentials(More)
The effects of the neuropeptide FMRFa on spontaneous excitatory postsynaptic currents (sEPSCs) and inhibitory postsynaptic currents (sIPSCs), as well as on evoked EPSCs and IPSCs, in two types of neurons within the central optic lobe of cuttlefish were examined using the whole-cell voltage-clamp technique. FMRFa (1-10 micro m) did not affect cell membrane(More)
The actions of the neuropeptide FMRFamide (Phe-Met-Arg-Phe-NH2) on the L-type (ICa,L) and T-type (ICa,T) calcium currents were investigated in muscle cells dissociated from the heart of squid, Loligo forbseii. The heart muscle cells could be divided into type I and type II cells, on the basis of morphological differences in the dissociated myocytes.(More)
A new tissue slice preparation of the cuttlefish eye is described that permits patch-clamp recordings to be acquired from intact photoreceptors during stimulation of the retina with controlled light flashes. Whole-cell recordings using this preparation, from the retinas of very young Sepia officinalis demonstrated that the magnitude, latency, and kinetics(More)
Artificial neural networks (ANNs) have become increasingly sophisticated and are widely used for the extraction of patterns or meaning from complicated or imprecise datasets. At the same time, our knowledge of the biological systems that inspired these ANNs has also progressed and a range of model systems are emerging where there is detailed information not(More)
Spontaneous excitatory postsynaptic currents (sEPSCs) were recorded from two different classes of neurons in the optic lobes of the cuttlefish brain and their synaptic activities analyzed and compared. The cell types were as follows: efferent centrifugal neurons, with cell bodies in the inner granule layer and axons projecting to the retina, and(More)
The effects of dopamine on spontaneous excitatory postsynaptic currents (sEPSCs) and inhibitory postsynaptic currents (sIPSCs) in three different classes of neurones within the optic lobe of cuttlefish were investigated using whole-cell voltage clamp techniques in a slice preparation. The neuronal types were centrifugal and amacrine neurones, located in the(More)
1. The formation of ectopic neuromuscular synapses was induced in rat soleus muscle by implantation of the fibular nerve into the proximal part of the muscle and subsequent sectioning of the soleus nerve. The gating properties of acetylcholine (ACh) receptors at the newly formed end-plates were examined by analysis of acetylcholine-induced membrane current(More)
Whole-cell voltage-clamp recordings from dissociated hair cells of the statocyst of octopus, Eledone cirrhosa, demonstrated that application of ACh, carbachol or muscarine (10 microM) reversibly decreased the amplitude of L-type calcium current (I(Ca,L)), while nicotine (10-100 microM) did not have any effect. Furthermore, atropine blocked the effect of ACh(More)