Two-stage reinforcement learning task predicts psychological traits.

External sources of information influence human actions. However, psychological traits (PTs), considered internal variables, also play a crucial role in decision making. PTs are stable across time and contexts and define the set of behavioral repertoires that individuals express.

Isomorphic decisional biases across perceptual tasks.

Humans adjust their behavioral strategies to maximize rewards. However, in the laboratory, human decisional biases exist and persist in two alternative tasks, even when this behavior leads to a loss in utilities. Such biases constitute the tendency to choose one action over others and emerge from a combination of external and internal factors that are specific for each individual.

Fictive Scratching Patterns in Brain Cortex-Ablated, Midcollicular Decerebrate, and Spinal Cats.

: The spinal cord's central pattern generators (CPGs) have been explained by the symmetrical half-center hypothesis, the bursts generator, computational models, and more recently by connectome circuits. Asymmetrical models, at odds with the half-center paradigm, are composed of extensor and flexor CPG modules. Other models include not only flexor and extensor motoneurons but also motoneuron pools controlling biarticular muscles.

Effects of Short-Term Random Noise Electrical Stimulation on Dissociated Pyramidal Neurons from the Cerebral Cortex.

Transcranial random noise electrical stimulation (tRNS) of the human brain is a non-invasive technique that can be employed to increase the excitability of the cerebral cortex; however, the physiological mechanisms remain unclear. Here we report for the first time the effects of short-term (250 ms) random noise electrical stimulation (RNS) on in-vitro acutely-isolated brain pyramidal neurons from the somatosensory and auditory cerebral cortex. We analyzed the correlation between the peak amplitude of the Na current and its latency for different levels of RNS.

The Spinal Neurons Exhibit an ON-OFF and OFF-ON Firing Activity Around the Onset of Fictive Scratching Episodes in the Cat.

In a previous report, we found neurons with ON-OFF and OFF-ON firing activity in the obex reticular formation during scratching. The aim of the present study was to examine whether the spinal neurons also exhibit this type of activity in relation to the "postural stage" of fictive scratching in the cat. We found that the extensor and intermediate scratching neurons exhibit an ON-OFF firing rate; conversely, the flexor neurons show an OFF-ON activity, relative to every scratching episode.

Optogenetic noise-photostimulation on the brain increases somatosensory spike firing responses.

We examined whether the optogenetic noise-photostimulation (ONP) of the barrel cortex (BC) of anesthetized Thy1-ChR2-YFP transgenic mice increases the neuronal multiunit-activity response evoked by whisker mechanical stimulation (whisker-evoked MUA). In all transgenic mice, we found that the signal-to-noise ratio (SNR) of such whisker-evoked MUA signals exhibited an inverted U-like shape as a function of the ONP level. Numerical simulations of a ChR2-expressing neuron model qualitatively support our experimental data.

Hind limb motoneurons activity during fictive locomotion or scratching induced by pinna stimulation, serotonin, or glutamic acid in brain cortex-ablated cats.

In brain cortex-ablated cats (BCAC), hind limb motoneurons activity patterns were studied during fictive locomotion (FL) or fictive scratching (FS) induced by pinna stimulation. In order to study motoneurons excitability: heteronymous monosynaptic reflex (HeMR), intracellular recording, and individual Ia afferent fiber antidromic activity (AA) were analyzed. The intraspinal cord microinjections of serotonin or glutamic acid effects were made to study their influence in FL or FS During FS, HeMR amplitude in extensor and bifunctional motoneurons increased prior to or during the respective electroneurogram (ENG).

Locomotion in intact and in brain cortex-ablated cats.

The current decerebration procedures discard the role of the thalamus in the motor control and decortication only rules out the brain cortex part, leaving a gap between the brain cortex and the subthalamic motor regions. In here we define a new preparation denominated Brain Cortex-Ablated Cat (BCAC), in which the frontal and parietal brain cortices as well as the central white matter beneath them were removed, this decerebration process may be considered as suprathalamic, since the thalamus remained intact. To characterize this preparation cat hindlimb electromyograms (EMG), kinematics and cutaneous reflexes (CR) produced by electrical stimulation of sural (SU) or saphenous (SAPH) nerves were analyzed during locomotion in intact and in BCAC.

Noise Improves Visual Motion Discrimination via a Stochastic Resonance-Like Phenomenon.

The stochastic resonance (SR) is a phenomenon in which adding a moderate amount of noise can improve the signal-to-noise ratio and performance of non-linear systems. SR occurs in all sensory modalities including the visual system in which noise can enhance contrast detection sensitivity and the perception of ambiguous figures embedded in static scenes. Here, we explored how adding background white pixel-noise to a random dot motion (RDM) stimulus produced changes in visual motion discrimination in healthy human adults.

Quantitative analysis of hindlimbs locomotion kinematics in spinalized rats treated with Tamoxifen plus treadmill exercise.

Locomotion recovery after a spinal cord injury (SCI) includes axon regeneration, myelin preservation and increased plasticity in propriospinal and descending spinal circuitries. The combined effects of tamoxifen and exercise after a SCI were analyzed in this study to determine whether the combination of both treatments induces the best outcome in locomotion recovery. In this study, the penetrating injury was provoked by a sharp projectile that penetrates through right dorsal and ventral portions of the T13-L1 spinal segments, affecting propriospinal and descending/ascending tracts.

Tamoxifen Promotes Axonal Preservation and Gait Locomotion Recovery after Spinal Cord Injury in Cats.

We performed experiments in cats with a spinal cord penetrating hemisection at T13-L1 level, with and without tamoxifen treatment. The results showed that the numbers of the ipsilateral and contralateral ventral horn neurons were reduced to less than half in the nontreated animals compared with the treated ones. Also, axons myelin sheet was preserved to almost normal values in treated cats.

Stochastic resonance in the synaptic transmission between hair cells and vestibular primary afferents in development.

The stochastic resonance (SR) is a phenomenon of nonlinear systems in which the addition of an intermediate level of noise improves the response of such system. Although SR has been studied in isolated hair cells and in the bullfrog sacculus, the occurrence of this phenomenon in the vestibular system in development is unknown. The purpose of the present study was to explore for the existence of SR via natural mechanical-stimulation in the hair cell-vestibular primary afferent transmission.

The hippocampus participates in the control of locomotion speed.

The hippocampus role in sensory-motor integration remains unclear. In these experiments we study its function in the locomotor control. To establish the connection between the hippocampus and the locomotor system, electrical stimulation in the CA1 region was applied and EMG recordings were obtained.

Transition of pattern generation: the phenomenon of post-scratching locomotion.

A fundamental problem in neurophysiology is the understanding of neuronal mechanisms by which the central nervous system produces a sequence of voluntary or involuntary motor acts from a diverse repertory of movements. These kinds of transitions between motor acts are extremely complex; however, they could be analyzed in a more simple form in decerebrate animals in the context of spinal central pattern generation. Here, we present for the first time a physiological phenomenon of post-scratching locomotion in which decerebrate cats exhibit a compulsory locomotor activity after an episode of scratching.

Aromatase and estrogen receptor alpha mRNA expression as prognostic biomarkers in patients with astrocytomas.

Estrogens are oncogenic hormones at a high level in breast, prostate, endometrial and lung cancer. Estrogens are synthesized by aromatase which has been used as a biomarker both in breast and lung cancer. Estrogen biological activities are executed by their classic receptors (ERα and ERβ).

Tamoxifen favoured the rat sensorial cortex regeneration after a penetrating brain injury.

A penetrating brain injury produces a glial scar formed by astrocytes, oligodendrocytes, microglia and NG2 cells. Glial scar is a barrier preventing the extent of damage but it has deleterious effects in the regeneration of the axons. Estradiol and tamoxifen reduce gliosis and have neuroprotective effects in the hippocampus and the spinal cord.