Hypnotic hallucination alters evoked potentials.

Studied whether the amplitude of the visual EP is reduced during hypnotic hallucination in which the S is instructed to perceive visual stimuli as diminished in brightness or obstructed from view. The visual EP responses of 6 high- and 6 low-hypnotizable Ss (aged 18–33 yrs) and of 6 undergraduate controls were compared in 3 hypnotic conditions: stimulus enhancement, stimulus diminution, and stimulus elimination (obstructive hallucination). ANOVA revealed that high-hypnotizable Ss demonstrated significant suppression of the later components of the EP response (N? and P?) while experiencing obstructive hallucinations, indicating a change in information processing. This effect was significantly greater in the right, as compared to the left, occipital region. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A decisional analysis of the effects of inferotemporal lesions in the rhesus monkey.

Modified signal detection procedures were used to analyze the effects of inferotemporal cortical resections in 2 experiments with a total of 14 adolescent rhesus monkeys. Results demonstrate (a) a severe difficulty in responding to differences in luminance; (b) a small but consistent change in sensitivity, which is attributed to an increased sensitivity to noise or a deficiency in the suppression of irrelevant aspects of the environment; and (c) an enhanced bias to respond to a nonrewarded stimulus (a lowering of criterion). This altered bias contrasts with the results obtained from limbic resections in a previous experiment, which produced a marked increase in bias to a rewarded contingency without influencing discrimination or detection. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The cognitive revolution and mind/brain issues.

Proposes that the convergence of data in the neuro- and computer sciences on psychological issues such as the nature of perception and the mechanisms of memory has led to a resurgence of interest in the mind/brain relationship. It is suggested that the relationship should be addressed in terms of scientific theory based on, but not limited to, philosophical inquiry, with each proposed stance examined not only in terms of logic but also by identifying the database to which the stance refers. Philosophical positions on the mind/brain relationship such as identity, dualism, interactionism, materialism, physicalism, and mentalism are described as theories that cannot be extended beyond their databases into overarching cosmologies. Concepts such as information, entropy, and energy are described as factors that are neutral to the mind/brain dichotomy. It is concluded that structural monism is primarily a neural monism that relates to such issues as procedural and transformational duality to resolve mind/brain dualism. (93 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computed tomography of Paget disease of the skull versus fibrous dysplasia

OBJECTIVE: Radiologists are often challenged to review CT examinations of the skull without pertinent clinical information or plain radiographs. Skull lesions of fibrous dysplasia (FD) may often be confused with Paget disease (PD). The purpose of this article is to evaluate radiographic similarities and to find the signs that can differentiate PD from FD of the skull on head CT and to describe the CT imaging features of PD and FD. DESIGN AND PATIENTS: CT scans of the skull in eight cases of PD, 18 cases of FD (13 cases of skull and facial bones, five cases of only facial bones) and 10 normals were studied retrospectively. RESULTS: Ten features were found to be similar in PD and FD and 10 other features were found to be dissimilar. The frequency of the 10 differentiating features was evaluated to determine their reliability in distinguishing one disorder from the other. The differentiating features in order of significance include: (1) "groundglass" appearance, (2) symmetry, (3) involvement of the paranasal sinuses, (4) thickness of the cranial cortices, (5) involvement of the sphenoid bone, (6) orbital involvement, (7) nasal cavity involvement, (8) presence of a soft tissue mass, (9) maxillary involvement, and (10) the presence of cyst-like changes. CONCLUSION: These 10 signs improve the radiologist's skill in differentiating FD and PD.     

Stages of brain and cognitive maturation.

H. T. Epstein (see PA, Vol 52:9783 and 1986), R. B. McCall (see record 1988-32308-001), and R. B. McCall et al (see record 1984-17419-001) presented discrepant findings regarding the presence of stages in brain and cognitive maturation, as described in Piagetian theory. This article questions whether their variables (e.g., skull circumference and global mental test scores) are appropriate indices from which to make such conclusions. Evidence from direct brain measurements (e.g., the quantitative electroencephalogram [QEEG]) and other neurobiological indices provides stronger support for the conclusion that regional brain maturation exhibits growth spurts and plateaus. The specific neuropsychological functions represented by regional QEEG maturation data give a composite picture of brain growth that is consistent with Piagetian theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decisional analysis of the effects of limbic lesions on learning in monkeys.

Examined the hypothesis that behavior during discrimination learning and reversal is under control of 2 competing variables: the patterned cues to be discriminated and the noncontingent schedule of reinforcement. An experiment was conducted with 8 adolescent rhesus monkeys using a modified decision theoretic procedure. Results show that the 2 variables were operative and that noncontingent reinforcement produced a strong position bias against discriminating. This bias was quantitatively more easily overcome by normal Ss than by Ss with hippocampal-amygdala lesions though the strategy and tactics used were the same for both groups. It is concluded that the hippocampus and amygdala influence attention through mechanisms that regulate motivational bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)