Different involvement of medial prefrontal cortex and dorso-lateral striatum in automatic and controlled processing of a future conditioned stimulus

A Videogame as a Tool for Clinical Screening of Possible Vulnerability to Impulsivity and Attention Disturbances in Children

An attention disturbance is a problem that affects many school-aged children. The assessment in children is usually report-based, and as a result, controversy surrounds the diagnosis. To solve this issue, the aim of this study was to develop a new tool to detect possible attention-related problems and impulsive behavior in 4- and 5-year-old children. This tool was developed as an Android app and could be used to provide an early indicator of possible future development problems. A sample of 103 children (48 girls and 55 boys) was randomly selected from primary schools and assessed by Pinky-Piggy, a videogame application based on a classical paradigm in experimental psychology. Data from this app were compared with a Child Neuropsychological Maturity Questionnaire. The subjects displayed different patterns of response to play a very simple game called Pinky-Piggy. The application discriminated between high-responders and low responders. The results showed a relationship between these two profiles and the levels of attention and neurodevelopment in each group. The tool could identify different types of profiles and demonstrated its potential to evaluate endophenotypes to predict attentional problems related to impulsive behavior. Additionally, it required less time and fewer tests to identify possible at-risk populations, thus assisting in clinical diagnosis.

Decreased GABAergic signaling, fewer parvalbumin-, somatostatin- and calretinin-positive neurons in brain of a rat model of simulated transport stress

Transport stress (TS) in animals lead to change in blood composition, brain structure, and the endocrine system as well as behavior. γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the mammalian central nervous system (CNS), influences many physiological functions and plays a significant role in coping with stress. This study aimed to explore the effect of stress on behavior, HPA axis, GABA transmitters and the distribution of GABAergic interneurons in the prefrontal cortex (PFC) and striatum of the brain by a rat model of simulated transport stress (STS). Thirty-six male Sprague Dawley rats were randomly divided into a control group (n = 12, no stress), a TS1d group (n = 12, 2 h stress for 1 d) and a TS7d group (n = 12, 2 h stress each day for 7 d). After STS, the rats were subjected to open-field testing (OFT) followed by serologic analysis, colorimetry, Western blot and immunohistochemistry. The total score of the OFT showed the similar profile with serum concentrations of corticosterone (CORT) and norepinephrine (NE), which in the TS7d group were all higher than the TS1d group but lower than the control group. STS also reduced GABA, glutamate decarboxylase 67 (GAD67) and GABA transporter 1 (GAT1) expression in the TS1d and these markers were increased in the TS7d, suggesting that GABA was related to hypothalamic-pituitary-adrenal (HPA) axis activation under stress. The number of parvalbumin (PV)-, somatostatin (SOM)-, and calretinin (CR)- positive cells were decreased with stress increase. Our findings revealed that STS affected the behavior of rats, synthesis and release of GABA by altering the HPA axis.

Sign and goal tracker rats process differently the incentive salience of a conditioned stimulus

Sign and goal tracker animals show different behavioral patterns in response to conditioned stimuli, which may be driven by different neural circuits involved in processing stimuli. Here, we explored whether sign and goal-tracker profiles implicated different brain regions and responses to incentive salience of stimuli. We performed three experiments using male Wistar rats. Experiment 1 showed that lesioning the medial prefrontal cortex increased the prevalence of the goal-tracker phenotype. Experiment 2 assessed the developmental trajectory of the salience incentive attribution to a conditioned stimulus, showing that increased incentive salience of stimuli increased the prevalence of the sign-tracker phenotype in mature, but not preadolescent rats. In experiment 3, the functional impact of the medial prefrontal cortex circuits was analyzed with a latent inhibition procedure. Sign tracker rats showed a reduced latent inhibition to stimuli previously exposed when compared to goal tracker or intermediate rats. The overall results of this study highlight a key role of the medial prefrontal cortex for sign tracking behavior. The expression of sign and goal tracker phenotypes changed after lesion to the medial prefrontal cortex (experiment 1), differed across development (experiment 2), and showed differences in the attentional processes to previously exposed stimuli, as preexposure to CS was ineffective in sign tracker animals (experiment 3). These data indicate that the responses to the incentive salience of stimuli in sign tracker and goal tracker profiles are likely driven by different neural circuitry, with a different role of prefrontal cortical function.

The Basal Ganglia: More than just a switching device

The basal ganglia consist of a variety of subcortical nuclei engaged in motor control and executive functions, such as motor learning, behavioral control, and emotion. The striatum, a major basal ganglia component, is particularly useful for cognitive planning of purposive motor acts owing to its structural features and the neuronal circuitry established with the cerebral cortex. Recent data indicate emergent functions played by the striatum. Indeed, cortico-striatal circuits carrying motor information are paralleled by circuits originating from associative and limbic territories, which are functionally integrated in the striatum. Functional integration between brain areas is achieved through patterns of coherent activity. Coherence belonging to cortico-basal ganglia circuits is also present in Parkinson's disease patients. Excessive synchronization occurring in this pathology is reduced by dopaminergic therapies. The mechanisms through which the dopaminergic effects may be addressed are the object of several ongoing investigations. Overall, the bulk of data reported in recent years has provided new vistas concerning basal ganglia role in the organization and control of movement and behavior, both in physiological and pathological conditions. In this review, basal ganglia functions involved in the organization of main movement categories and behaviors are critically discussed. Comparatively, the multiplicity of Parkinson's disease symptomatology is also revised.