Comparison of behaviors elicited by electrical brain stimulation in dorsal brain stem and hypothalamus of rats.

Four brain-stimulation phenomena elicited from both dorsal brain stem and hypothalamic sites were investigated with the following results: (a) intracranial self-stimulation rate-intensity functions for dorsal brain stem and hypothalamic sites yielded very high (over 1,000 responses/15 min.) to moderate (201-500 responses/15 min.) response rates; (b) d-amphetamine produced higher response rates than either l-amphetamine or saline at both dorsal brain stem and hypothalamic sites, indicating that noradrenergic dorsal brain stem fibers (or cell bodies) support intracranial self-stimulation; (c) dorsal brain stem and hypothalamic self-stimulation sites reliably produced escape behavior; (d) simultaneous stimulation of dorsal brain stem and hypothalamic sites at subthreshold intensities interacted to produce suprathreshold response rates.     

IQ and scores on the Mini-Mental State Examination (MMSE): controlling for effort and education among geriatric inpatients

The Mini-Mental State Examination (MMSE) and the Peabody Picture Vocabulary Test, Third Edition (PPVT-III) were administered to 76 Extended Care Center inpatients of a Veterans Affairs Medical Center, 56 of whom did not carry a diagnosis associated with brain impairment, and 20 of whom had a diagnosis associated with degenerative or cerebrovascular conditions. MMSE and PPVT-III scores, the latter of which estimates verbal IQ, were significantly correlated in both groups, even when controlling for the effects of education. This correlation was attenuated, but remained significant, in the face of varying levels of patient effort. The findings of this study support earlier findings, which also suggest that interpretation of "impaired" performance on the MMSE for those with IQ scores below 90 should be interpreted with caution. Average MMSE scores for Wechsler IQ classifications are provided.