Orlando F.A. Bueno

Depression, anxiety and quality of life scores in seniors after an endurance exercise program

OBJECTIVE Mood disorders are a frequent problem in old age, and their symptoms constitute an important public health issue. These alterations affect the quality of life mainly by restricting social life. The participation in a regular exercise program is an effective way of reducing or preventing the functional decline associated with aging. The aim of the present study was to examine the effects of fitness-endurance activity (at the intensity of Ventilatory Threshold 1 (VT-1)) in depression, anxiety and quality of life scores in seniors. METHODS The study involved 46 sedentary seniors aged 60-75 (66.97 +/- 4.80) who were randomly allocated to two groups: 1) Control group, which was neither asked to vary their everyday activities nor to join a regular physical fitness program; and 2) Experimental group, whose members took part in an aerobic fitness program consisting of ergometer cycle sessions 3 times a week on alternate days for six months working at a heart rate corresponding to ventilatory threshold (VT-1) intensity. Subjects were submitted to a basal evaluation using the geriatric depression screening scale--GDS, STAI trait/state (anxiety scale) and SF-36 (quality of life scale). RESULTS Comparing the groups after the study period, we found a significant decrease in depressive and anxiety scores and an improvement in the quality of life in the experimental group, but no significant changes in the control group. CONCLUSION The data suggest that an aerobic exercise program at VT-1 intensity suffices to promote favorable modifications in depressive and anxiety scores to improve the quality of life in seniors.

Strategies used by hippocampal- and caudate-putamen-lesioned rats in a learning task.

In rats, hippocampal lesions result in impairment of spatial navigation, although other learning abilities remain unaltered. When learning a left/right discrimination task, rats can use a spatial strategy (with external maze landmarks-Situation 1) or are forced to use an egocentric strategy (without external or internal maze cues-Situation 2). Little is known about the extrahippocampal systems involved in the utilization of egocentric strategy. It is suggested that striatum could play an important role in the learning abilities that are spared after hippocampal lesion. The aim of our study was to investigate which strategy is used by rats bearing hippocampal or caudate-putamen lesions in the acquisition of a left/right discrimination task in an elevated T-maze in both Situations 1 and 2. We also investigated the effect of each lesion on the reversal of discrimination in both situations. Acquisition was not altered in any of the situations; however, a transfer test showed that hippocampal-lesioned rats used a different strategy (egocentric) from control animals (spatial) in Situation 1. In addition, reversal of the discrimination was impaired in Situation 2. Caudate-putamen lesion produced a transient effect on reversal of discrimination only in the egocentric task (Situation 2), but did not impair acquisition of the task in either situation, thus suggesting that the animals were able to use either strategy.

Dissociated paradoxical sleep deprivation effects on inhibitory avoidance and conditioned fear

Rats were submitted to paradoxical sleep deprivation (PSD) for 24, 72, or 96 h and were trained on a double aversively motivated task, encompassing a step-through inhibitory avoidance and a classical conditioning of fear to a brief tone serving as conditional stimulus. Retention test of the inhibitory avoidance was performed at the same apparatus of training (without tone presentation). Retention of conditioned fear was assessed in an open field apparatus, where the freezing reaction to the tone was measured. PSD for 24 and 72 h preceding the training session had no effect on either task. However, PSD during the 96 h preceding the training session impaired acquisition of inhibitory avoidance, but had no effect on classically conditioned fear. It is concluded that PSD had differential effects on the two tasks, both aversively motivated and trained at the same time and conditions.

Effects of dorsal striatum lesions in tone fear conditioning and contextual fear conditioning

It has been suggested that the striatum mediates hippocampus-independent memory tasks. Classical fear conditioning to a discrete stimulus such as a tone is not affected by hippocampal lesion, whereas contextual fear conditioning is an hippocampus dependent task. The purpose of the present study was to verify the effect of dorsal striatal lesions on tone and contextual fear conditioning. The lesioned rats were not impaired in contextual fear conditioning but in tone fear conditioning both electrolytically and neurotoxically lesioned animals showed less freezing compared with controls. The lesion effect was observed after a postoperative recovery period of 14 days but not after 2 months. The results support the hypothesis that the dorsal striatum is involved in hippocampus-independent memory tasks, but, in spite of this involvement, it does not seem to be a critical structure.

Social stress does not interact with paradoxical sleep deprivation-induced memory impairment

Extensive evidence has linked both paradoxical sleep (PS) and stress to memory processing. The purpose of the present study was to examine the effect of social instability stress on memory and to verify whether this stress interferes with the amnesic effect of PS deprivation using the modified multiple platform method. In addition to the PS-deprived group (put onto narrow platforms inside the deprivation tanks) two control groups were used: one of them remained in its home-cages and the other was placed inside the deprivation tanks, onto a grid that contained large platforms on it. All groups were subdivided in socially stable and unstable conditions. Immediately after 96 h of sleep deprivation, the animals were trained in three different memory tasks: inhibitory avoidance, classical fear conditioning to a discrete stimulus and contextual fear conditioning. Twenty-four hours after training, the animals were tested in order to assess task acquisition. The results showed that social instability did not impair the performance of animals nor interacted with PS deprivation in any of the tasks. Grid control animals presented a selective impairment in the inhibitory avoidance task and contextual, but not in the classical, fear conditioning task, compared to cage control rats. This finding could be due to the stress to which grid control animals were exposed (humidity and luminosity) during the manipulation period. PS-deprived animals exhibited poorer performance than the other groups in all tasks. As they also showed an increased threshold to shock-induced vocalisation, but not to flinch response, it is not possible to completely rule out a decreased response to noxious stimulation as a contributing factor for the present results with PS deprivation.

Deficits in avoidance responding after paradoxical sleep deprivation are not associated with altered [3H]pirenzepine binding to M1 muscarinic receptors in rat brain.

Previous work had indicated that animals that were sleep-deprived and then trained on a passive avoidance task show poor retention of the task 24 h later after being allowed to sleep freely again. Cholinergic involvement is suggested by the fact that this effect is prevented by treatment with the muscarinic agonist pilocarpine during sleep deprivation. The observation that similar deficits are observed in non-deprived rats after treatment with M1-selective antagonist compounds such as dicyclomine or pirenzepine cause similar impairments, and gave rise to the hypothesis that sleep deprivation might induce significant reductions in M1 binding in brain areas involved in learning and memory processes. Rats were deprived of sleep for 96 h and then either immediately killed, or allowed to recover sleep for 24 h before being killed. [3H]pirenzepine binding to M1 sites was examined by quantitative autoradiography in 39 different brain areas in cage controls, sleep-deprived and sleep-recovered animals (N=8 per group). No significant differences among groups were found in any brain region. A separate group of animals was subjected to the sleep deprivation procedure and then trained in a simple avoidance task. Animals were then allowed to sleep and retested 24 h later. This group showed a significant impairment in the avoidance task compared to cage controls, in agreement with previous observations. These data suggest that proactive learning/memory deficits induced by sleep deprivation cannot be attributed to altered M1 binding either immediately after deprivation (when avoidance training occurs) or after sleep has recovered (when acquisition/retention are tested). The possibility remains that alterations in M1 function occur at post-membrane second messenger systems.

The indirect amygdala-dorsal striatum pathway mediates conditioned freezing: insights on emotional memory networks.

The dorsal striatum (DS) is involved in various forms of learning and memory such as procedural learning, habit learning, reward-association and emotional learning. We have previously reported that bilateral DS lesions disrupt tone fear conditioning (TFC), but not contextual fear conditioning (CFC) [Ferreira TL, Moreira KM, Ikeda DC, Bueno OFA, Oliveira MGM (2003) Effects of dorsal striatum lesions in tone fear conditioning and contextual fear conditioning. Brain Res 987:17-24]. To further elucidate the participation of DS in emotional learning, in the present study, we investigated the effects of bilateral pretest (postraining) electrolytic DS lesions on TFC. Given the well-acknowledged role of the amygdala in emotional learning, we also examined a possible cooperation between DS and the amygdala in TFC, by using asymmetrical electrolytic lesions, consisting of a unilateral lesion of the central amygdaloid nucleus (CeA) combined to a contralateral DS lesion. The results show that pre-test bilateral DS lesions disrupt TFC responses, suggesting that DS plays a role in the expression of TFC. More importantly, rats with asymmetrical pre-training lesions were impaired in TFC, but not in CFC tasks. This result was confirmed with muscimol asymmetrical microinjections in DS and CeA, which reversibly inactivate these structures. On the other hand, similar pretest lesions as well as unilateral electrolytic lesions of CeA and DS in the same hemisphere did not affect TFC. Possible anatomical substrates underlying the observed effects are proposed. Overall, the present results underscore that other routes, aside from the well-established CeA projections to the periaqueductal gray, may contribute to the acquisition/consolidation of the freezing response associated to a TFC task. It is suggested that CeA may presumably influence DS processing via a synaptic relay on dopaminergic neurons of the substantia nigra compacta and retrorubral nucleus. The present observations are also in line with other studies showing that TFC and CFC responses are mediated by different anatomical networks.

A longitudinal study of a neuropsychological rehabilitation program in Alzheimer's disease

UNLABELLED Our aim was to study the duration of benefits derived from a neuropsychological rehabilitation program (NRP) for dementia patients. METHOD The participants in this study were three patients diagnosed as probable Alzheimers disease in the initial-to-moderate phase; the three were taking anticholinesterases. They were submitted to a neuropsychological evaluation (NE) before the NRP and then reevaluated after 12 and 24 months of treatment. The aim of our intervention was to do practical work with implicit and explicit residual memory by training them in everyday life activities, and using compensatory strategies and their intact cognitive abilities. RESULTS Analysis of quantitative NE data (descriptive measures) after the first year of NRP showed cognitive improvement, functional stabilization and fewer behavioral problems. However, this improvement did not continue in the second year, and the disease maintained its characteristic progression.

Acute cognitive effects of donepezil in young, healthy volunteers

The acute nootropic potential of donepezil in young healthy volunteers has not been adequately investigated mainly because in previous studies: (1) effects were assessed before peak‐plasma concentration (Tmax) was reached; (2) only a few cognitive processes were assessed. Here we investigated a myriad of cognitive effects of augmentation of acetylcholine using an acute dose of donepezil in healthy adults at theoretical Tmax.

Chounergic modulation of inhibitory avoidance impairment induced by paradoxical sleep deprivation

1. Male Wistar rats were submitted to paradoxical sleep deprivation for 96 hr by a modified multiple platform technique. 2. Training of step-through inhibitory avoidance was performed immediately after the last day of paradoxical sleep deprivation. Twenty-four hr after training the animals were submitted to the retention test. 3. In Experiment 1, pilocarpine (4 mg/kg, i.p.) or atropine (4 mg/kg, i.p.) were administered daily during the paradoxical sleep deprivation period. Pilocarpine, but not atropine, reversed the impairment induced by PS deprivation. 4. In Experiment 2, pilocarpine (4, 8 and 12 mg/kg, i.p.) was injected 1 hr before training in order to verify if the reversal of memory impairment was an effect secondary to residual enhanced blood levels of pilocarpine during training. Acute treatment with pilocarpine, in any dose, did not reverse the impairment produced by paradoxical sleep deprivation 5. Activation of the cholinergic system during the period of deprivation is able to prevent memory deficits induced by paradoxical sleep deprivation.