Five rhesus macaques monkeys surgically prepared with Thiry small intestinal (jejunum) loops and implanted brain electrodes were restrained in primate chairs and kept on 23-hr deprivation-feeding cycle. After being trained to press a lever for sugar pills on an FR 25 schedule of reinforcement, a discrimination training procedure was established. Lever presses were reinforced during the S(D)-a non-aversive mechanical stimulus applied to the internal walls of the Thiry loop by rhythmic inflation-deflation of a small latex balloon by air at the rate of one cycle per sec at 100 mm Hg pressure. The S(Delta) was the absence of the visceral stimulation. The monkeys successfully discriminated between presence and absence of the internal stimulus. A discrimination reversal was attempted and completed on one monkey. The results clearly show operant discrimination based on an interoceptive stimulus. Cortical and subcortical EEG records reflected the onset but not termination of the visceral stimulation.

Animals↗

PubMed1959

Some neural and behavioral correlates of electrical self-stimulation of the limbic system.

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Journal Article↗

PubMedDate not supplied

Backache and the lumbar spinal canal.

This paper records measurement of the lumbar spinal canal by diagnostic ultrasound in more than 700 subjects from early infancy until the age of 65 years. It demonstrates the range of canal size in a South Yorkshire population. The canal is relatively wide in children, reaches a maximum diameter in the late teens, and reduces slightly by late adult life. This does not appear to be related to occupation. Comparisons are made with more than 700 patients with symptoms of back pain, especially patients with disabling disc symptoms, root entrapment syndrome, and neurogenic claudication. The size of the central canal is particularly significant in patients who have neurogenic claudication and disc symptoms. It is less significant in root entrapment syndrome.

Adolescent↗

PubMedDate not supplied

The natural history of root entrapment syndrome.

An attempt was made to recognize entrapment of the lumbar root within the root canal using four criteria; (1) severe, constant root pain to the lower leg, (2) pain unrelieved by bed rest, (3) minimal tension signs, and (4) patients over 40 years of age. Two hundred forty-nine patients fulfilled the criteria, representing 11% of patients attending a back pain clinic. Most had restricted spinal extension, but few had abnormal neurologic signs. Degenerative change was common, especially disc space reduction. Central canal size measured by ultrasound was normal, compatible with a variable past history of back pain. Patients with a long history of back pain numbered 80%, and 90.4% were managed by nonoperative means. Although 78% of these still had some root pain between 1 and 4 years after first attendance, most of them were not troubled sufficiently to have sought alternative help.

Adult↗

PubMedDate not supplied

Back pain and trunk list.

An association of trunk list with back pain was recorded in 100 patients, 5.6% of those attending a back pain clinic. Twice as many patients listed to the left as to the right. A total of 49 patients fulfilled the criterion of a symptomatic lumbar disc lesion, and 20 required surgical excision of the disc. The side of the list was not related to the side of the sciatica nor to the topographic position of the disc in relation to the nerve root. There is some evidence that the side of the list may be related to hand or leg dominance.

Adult↗

PubMedDate not supplied

Intradural primary chondroblastic osteosarcoma: case report.

We report a rare case of intradural primary osteosarcoma (IPOS) in a 74-year-old man with aphasia and right-sided hemiparesis. Radiologic workup revealed a large, partially calcified, left-sided frontotemporal intracranial mass lesion. At surgery, the tumor was found to be entirely intradural; it involved the brain and subarachnoid space of the left sylvian fissure. The adjacent dura was uninvolved. Neuropathologic findings confirmed the diagnosis of chondroblastic osteosarcoma. To our knowledge, this is the sixth reported case of IPOS and the first reported case of the chondroblastic subtype.

Aged↗