Neural substrates of olfactory discrimination learning with auditory secondary reinforcement. I. Contributions of the basolateral amygdaloid complex and orbitofrontal cortex

The basolateral amygdaloid complex (BLA) and orbitofrontal cortex (OFC) share extensive reciprocal connections, and interactions between these regions likely contribute to both mnemonic and affective processes. The present study examined the potential differential contributions of the BLA and OFC to performance of an olfactory discrimination task that incorporates auditory conditioned reinforcement and to expression of immediate post-shock freezing behavior. Damage to the BLA had little effect on performance of the conditioned reinforcement task but abolished immediate post-shock freezing behavior. In contrast, damage to OFC resulted in both a mild but significant performance decrement in the conditioned reinforcement task and a significant attenuation of immediate post-shock freezing behavior. These findings suggest that immediate post-shock freezing behavior is likely critically dependent upon interactions between the BLA and OFC. However, although mnemonic processes underlying accurate performance of the conditioned reinforcement task might be supported by OFC in part, such processes are independent of either the BLA or interactions between these two regions.     

Metamorphosis of the Mushroom Bodies; Large-Scale Rearrangements of the Neural Substrates for Associative Learning and Memory in Drosophila

Paired brain centers known as mushroom bodies are key features of the circuitry for insect associative learning, especially when evoked by olfactory cues. Mushroom bodies have an embryonic origin, and unlike most other brain structures they exhibit developmental continuity, being prominent components of both the larval and the adult CNS. Here, we use cell-type-specific markers, provided by the P{GAL4} enhancer trap system, to follow specific subsets of mushroom body intrinsic and extrinsic neurons from the larval to the adult stage. We find marked structural differences between the larval and adult mushroom bodies, arising as the consequence of large-scale reorganization during metamorphosis. Extensive, though incomplete, degradation of the larval structure is followed by establishment of adult specific α and β lobes. Kenyon cells of embryonic origin, by contrast, were found to project selectively to the adult γ lobe. We propose that the γ lobe stores information of relevance to both developmental stages, whereas the α and β lobes have uniquely adult roles.     

Marked Retrograde and Anterograde Amnesia of a Visual Discrimination Task in Rats with Selective Lesions of the Perirhinal Cortex

Damage to the temporal cortex (TC), the lateral entorhinal cortex (LEC), or their interconnections has disruptive effects on visual memory. The fiber connections between TC and LEC are relayed in the perirhinal cortex (PC) or in the adjacent white matter of PC. PC seems to make up a particularly important structure for mnemonic processing. The purpose of the present study was to examine whether selective PC lesions might affect retroactive or proactive memory, since TC/LEC transections can cause both retrograde and anterograde amnesia. The results show that both PC and TC/LEC lesions impair retroactive memory to similar degrees (Experiment 1). However, PC lesions yielded a slightly stronger impairment of both acquisition and retention in the proactive paradigm than TC/LEC lesions (Experiment 2). These findings give support to the notion that PC plays an important role in formation of memory.     

Use of the MMPI-2 in American Indians: I. Comparability of the MMPI-2 between two tribes and with the MMPI-2 normative group

The comparability of the MMPI-2 in American Indians with the MMPI-2 normative group was investigated in a sample of 535 Southwestern and 297 Plains American Indian tribal members with contrasting sociocultural and historical origins. Both American Indian tribal groups had clinically significant higher T scores (> 5 T points) on 5 validity and clinical scales, 6 content scales, and 2 supplementary scales than did the MMPI-2 normative group. There were no significant differences between the 2 tribal groups on any of the MMPI-2 clinical, content, or supplementary scales. Matching members of both tribes with persons in the MMPI-2 normative group on the basis of age, gender, and education reduced the magnitude of the differences between the 2 groups on all of these scales, although the differences in T scores still exceeded 5 T points. It appears likely that the MMPI-2 differences of these 2 American Indian groups from the normative group may reflect their adverse historical, social, and economic conditions.     

How do I feel about the behavior? The interplay of affective associations with behaviors and cognitive beliefs as influences on physical activity behavior.

Individuals have affective associations with health behaviors. In other domains such associations have been shown to influence behavior, but affective associations with health behaviors are not included in current health decision-making models. The authors examined whether affective associations with exercise predicted individuals' activity behavior and, if so, how they interfaced with other decision-making constructs to influence behavior. Adult participants (N = 433) reported their current physical activity behavior and affective associations with physical activity. Health belief model and theory of planned behavior constructs were also assessed. More positive affective associations with activity significantly predicted greater activity behavior. Moreover, the influence of the health belief model and theory of planned behavior constructs on activity behavior was mediated through affective associations. Affective associations were shown to play a central role in individuals' activity behavior, both as a mediator of the effects of cognitively based decision-making factors and as an independent predictor of activity behavior. The results suggest the need to include affective influences on behavior in formal models of health decision making and, potentially, to explore affectively based intervention routes to change behaviors.