Rats received bilateral injections of the excitotoxin, N-methyl-D,L aspartate, which resulted in degeneration of basal forebrain cholinergic (BFC) neurons in the nucleus basalis magnocellularis. Most tests of general neurological function revealed no differences between control rats and those with BFC lesions and where differences were found they appeared to be due to hyperemotionality. Rats with BFC lesions demonstrated significant deficits in working memory, as evaluated in an 8-arm radial maze. In addition, these rats showed a severe impairment in tactile discrimination learning, an effect of BFC lesions not previously demonstrated. We propose that cholinergic deafferentation of the somatosensory cortex with consequent disruption in somatosensory information processing might account at least in part for this effect.

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PubMedDate not supplied

CT manifestation in the pararectal area following fast neutron radiotherapy.

Sixty-four pelvic CT studies of 38 patients with pelvic malignancies were obtained at various times (21 to 678 days) following fast neutron radiotherapy. Multiple scans (2 to 3) were available in 19 cases. Fractionated neutron radiotherapy was delivered over four to seven weeks to a total dose of 54 Gy to 60 Gy photon equivalent. Radiation-induced changes on CT were symmetrical thickening of the perirectal fascia (87%), widening of the presacral space (82%), and thickening of the walls of the bladder and rectum (21% and 11%, respectively). Serial CT studies showed that these changes became stable after 12 weeks from radiotherapy in 13 of 14 patients (93%). CT manifestations of radiation-induced changes in the pararectal area were rather regular and would be easy to differentiate from local recurrence or secondary disease.

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