Modulation of the basal forebrain neural activity related to efficiency of reaching for food movements in rat

In the course of learning, single unit activity of basal forebrain neurons was recorded in freely moving rats. Modulation of the neural activity related to efficiency of reaching for food movements was observed between a 40% of the recorded neurons. The firing-rate of such neurons increased during retrieval of the food. Conversely, the activity of these neurons decreased or did not change during unsuccessful movements. In the most neurons (57.1%) the modulation of the activity was observed at the second half of time interval of the movement, but before finishing its. Some neurons (35.7%) changed their activity after the movements.     

Neurobiology of addictive behavior

Addictive behavior developes after repeated substance use and it typically include a strong desire to take the drug, difficulties in controlling its use, persisting in its use despite harmful consequences, a higher priority given to the drug use than to other activities. Relapse, the resumption of drug taking after periods of abstinence, remains the major problem for the treatment of addiction. The process of drug addiction shares striking commonalities with neural plasticity associated with natural reward learning and memory and is caused primarily by drug-induced sensitization in the brain mesocorticolimbic systems that attribute incentive salience to reward-associated stimuli. The switch from controlled to compulsive drug seeking represents a transition at the neural level from prefrontal cortical to striatal control. Current neurophysiologic evidence suggests that the development of addiction is to some extent due to neurochemical stimulation of the midbrain dopaminergic system that is traditionally considered as a 'common neural currency' for rewards of most kinds. Addictions are a result of the interplay of multiple genetic and environmental factors. They are characterized by phenotypic and genetic heterogeneity as well as polygenicity. Environmental factors are crucial in addiction vulnerability and resistese too.     

Selective interactions of boundaries with upstream region of Abd-B promoter in Drosophila bithorax complex and role of dCTCF in this process

Expression of the genes Ubx, abd-A, and Abd-B of the bithorax complex depends on its cis-regulatory region, which is divided into discrete functional domains (iab). Boundary/insulator elements, named Mcp, Fab-6, Fab-7 and Fab-8 (PTS/F8), have been identified at the borders of the iab domains. Recently, binding sites for a Drosophila homolog of the vertebrate insulator protein CTCF have been identified in Mcp, Fab-6 and Fab-8 and also in several regions that correspond to predicted boundaries, Fab-3 and Fab-4 in particular. Taking into account the inability of the yeast GAL4 activator to stimulate the white promoter when the activator and the promoter are separated by a 5-kb yellow gene, we have tested functional interactions between the boundaries. The results show that all dCTCF-containing boundaries interact with each other. However, inactivation of dCTCF binding sites in Mcp, Fab-6 and PTS/F8 only partially reduces their ability to interact, suggesting the presence of additional protein(s) supporting distant interactions between the boundaries. Interestingly, only Fab-6, Fab-7 (which contains no dCTCF binding sites) and PTS/F8 interact with the upstream region of the Abd-B promoter. Thus, the boundaries might be involved in supporting the specific interactions between iab enhancers and promoters of the bithorax complex.     

Infectious disease mortality in the USSR

In recent decades infectious and parasitic diseases (class 1 according to the International Classification of Diseases-9) constitute 2-3% of causes in the total morbidity structures in the USSR. The main causes of death among diseases of class 1 are tuberculosis (37%), acute enteric infections (30%), septicemia (11%), viral hepatitides (11%), meningococcal infection (4%), measles (2%). The main groups are children aged up to 2 years (48% of fatal cases of diseases belonging to class 1). The territorial irregularity of mortality indices has been revealed.     

Study of the enhancer-blocking activities of new boundaries in the <Emphasis Type="Italic">bithorax</Emphasis> complex of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

It was shown earlier that the Mcp, Fab-7, and Fab-8 boundaries of the bithorax complex contain insulators that effectively block the enhancers of the yellow and white genes. Other boundaries have not been studied so far. The recent mapping of binding sites for the insulator protein dCTCF in the regulatory regions of the bithorax complex genes permitted the Fab-3, Fab-4, and Fab-6 boundaries to be localized. Here, we showed that, despite the presence of dCTCF-binding sites, fragments of the Fab-3, Fab-4, and Fab-6 boundaries do not exhibit the properties of insulators in the model system with the yellow and white genes. Moreover, in some regions of the genome the Fab-4 and Fab-6 boundaries display the properties of silencers.     

Activity of neurons in the pedunculopontine nucleus in conditioned instrumental appetitive reflex

Activity of 91 neurons in the compact and diffuse parts of the pedunculopontine tegmental nucleus (PPTg) was recorded in freely moving rabbits during execution of instrumental appetitive conditioning. Of the recorded neurons, 37.4% changed their activity in response to a conditioned stimulus, which is the evidence for the PPTg involvement in instrumental conditioning. Excitatory conditioned neuronal responses to the conditioned stimulus and food reinforcement significantly prevailed over inhibitory reactions. Neuronal responses to the conditioned stimulus were classified in several basic patterns reflecting stimulus effects, structure of the behavioral act, and reinforcement properties. These reactions indicate the involvement of the PPTg in attention, motor learning, and reinforcement. The revealed differences in associative reactive properties of the compact and diffuse parts of the PPTg to the conditioned stimulus and reinforcement point to the functional heterogeneity of this structure and suggest the leading role of the cholinergic part of the PPTg in instrumental appetitive conditioning and reinforcement as well as the essential contribution of the diffuse part into classical appetitive conditioning.     

Activity of neurons in the pedunculopontine nucleus during defensive instrumental conditioning

The activity of 109 neurons in the compact and diffuse parts of the pedunculopontine tegmental nucleus (PPTg) was recorded in freely moving rabbits during the acquisition and actualization of the defensive instrumental conditioned reflex. It was found that 47% of the recorded neurons responded to a conditioned stimulus (CS). This finding suggests the involvement of the PPTg in the instrumental conditioning. A significant prevalence of the excitatory conditioned responses to the CS suggests the predominantly activating influence of the PPTg on its projection structures during conditioning. The neuronal responses to the CS were classified into several basic patterns reflecting stimulus effects, the structure of the behavioral act, and the nature of the reinforcement. They indicated the involvement of the PPTg in attention, motor learning, and reinforcement. A significant decrease in the reactivity of the CS of the PPTg neurons as a result of learning specialization was shown. The revealed differences in the associative and reactive properties (with respect to CS) between the neurons of the compact and diffuse PPTg parts testify to the functional heterogeneity of this structure and suggest the leading role of the cholinergic compact part of the PPTg in the instrumental defensive conditioning. Thus, the obtained evidence suggests the involvement of the PPTg in the mechanisms of attention and acquisition of the active defensive motor conditioning.