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Biomedical subjects

S Pateromichelakis

Publications and source records attributed to S Pateromichelakis.

25 records · Page 2Linked to original sources
PubMed1981

Response properties of visual units in the anterior dorsolateral thalamus of the chick (Gallus domesticus).

Receptive fields of neurons in the anterior dorsolateral thalamus (DLA) of the chick were plotted and their response properties analyzed. The average size was 18 degrees X 13 degrees but there were some wide-field units. DLA cells were classified as detectors of 1. general movement (uniform-field), 22%; 2. general movement (centre-periphery), 22%; 3. moving dark objects, 29%; 4. direction, 8%; and 5. illumination, 19%.

Animals↗
PubMed1981

Inflammation and peripheral nerve sensitisation.

It is a well recognised phenomenon that acute inflammation often interferes with the success of local analgesia. It has been suggested recently that this apparent reduction in the efficiency of the local anaesthetic is due to an increase in peripheral nerve activity. This investigation was undertaken to identify possible alternations in the impulses evoked in sensory nerves in the presence of inflammation. The saphenous nerve was exposed in the thigh of an anaesthetised rat. Stimulating and recording electrodes were applied under paraffin oil and an area of skin supplied by the nerve was identified. An electronically driven mechanical probe was used to apply a repeatable tap of short duration to the skin, and the force was adjusted so that a submaximal evoked potential was produced. A number of these potentials were averaged electronically. Inflammatory changes were induced in he skin by electrical antidromic stimulation and the mechanical stimulation schedule was repeated. The evoked action potential was shown to have increased substantially. These results are considered in conjunction with findings of other investigators who have shown a similar sensitisation using multifibre preparations.

Action Potentials↗
PubMed1979

Response properties of units in the lateral geniculate nucleus of the domestic chick (Gallus domesticus).

One hundred and four visual units of the (ventral) lateral geniculate nucleus (GL) of chicks (Gallus domesticus) were studied with extracellular microelectrodes. Most were extremely responsive to moving targets even at low speeds (0.1 degrees/sec). They were classified as follows. (1) movement-sensitive units with uniform, restricted receptive fields (47%). (2) Movement-sensitive units with small receptive fields possessing regions responding to differing modes of stimulation ('center-periphery units'). (3) Movement-sensitive neurons with uniform, wide receptive fields, larger than 75 degrees x 65 degrees (15%). (4) Movement-insensitive cells, responsive only to illumination changes (7%). (5) Units with indeterminate receptive fields, a poor visual response or a poor response to movement (14%). The firing of neurons in classes I-III was mostly an accurate function of target speed; half of them also provided accurate monitoring of the beginning, course and termination of target movement (tonic units). In view of the above, the high proportion of directionally selective cells (31%) and the large size of many of its receptive fields, the GL is considered as a candidate structure for optomotor integration but the evidence is otherwise scant. There is, however, an apparent contribution to its unit properties from both retinal ganglion cells and neurons from different tectal layers. Whatever its role, it is unlikely to be the functional homologue to the mammalian ventral lateral geniculate as the unit properties of two structures differ substantially.

Animals↗