Newborn infants learn during sleep

Newborn infants must rapidly adjust their physiology and behavior to the specific demands of the novel postnatal environment. This adaptation depends, at least in part, on the infant's ability to learn from experiences. We report here that infants exhibit learning even while asleep. Bioelectrical activity from face and scalp electrodes was recorded from neonates during an eye movement conditioning procedure in which a tone was followed by a puff of air to the eye. Sleeping newborns rapidly learned the predictive relationship between the tone and the puff. Additionally, in the latter part of training, these infants exhibited a frontally maximum positive EEG slow wave possibly reflecting memory updating. As newborns spend most of their time sleeping, the ability to learn about external stimuli in the postnatal environment during nonawake states may be crucial for rapid adaptation and infant survival. Furthermore, because eyelid conditioning reflects functional cerebellar circuitry, this method potentially offers a unique approach for early identification of infants at risk for a range of developmental disorders including autism and dyslexia

Lateral inhibition in visual cortex of migraine patients between attacks

BACKGROUND: The interictal deficit of habituation to repetitive visual stimuli in migraine patients could be due to deficient intracortical inhibition and/or to low cortical pre-activation levels. Which of these abnormalities contributes more to the habituation deficit cannot be determined with the common methods used to record transient visual responses. We investigated lateral inhibition in the visual cortex during the migraine cycle and in healthy subjects by using differential temporal modulations of radial windmill-dartboard (WD) or partial-windmill (PW) visual patterns. METHODS: Transient (TR-VEP) and steady-state visual-evoked potentials (SS-VEP) were recorded in 65 migraine patients (21 without and 22 with aura between attacks; 22 patients during an attack) and in 21 healthy volunteers (HV). Three stimulations were used in each subject: classic checkerboard pattern (contrast-reversion 3.1Hz), WD and PW (contrast-reversion ~4Hz). For each randomly presented stimulation protocol, 600 sweeps were acquired and off-line partitioned in 6 blocks of 100. Fourier analysis allowed data to extract in SS-VEP the fundamental (1H) and the second harmonic (2H) components that reflect respectively short-(WD) and long- range lateral inhibition (attenuation of 2H in WD compared to PW). RESULTS: Compared to HV, migraineurs recorded interictally had significantly less habituation of the N1-P1 TR-VEP component over subsequent blocks and they tended to have a smaller 1(st) block amplitude. 1H amplitude in the 1(st) block of WD SS-VEP was significantly greater than in HV and habituated in successive blocks, contrasting with an amplitude increase in HV. Both the interictal TR-VEP and SS-VEP abnormalities normalized during an attack. There was no significant between group difference in the PW 2H amplitude and its attenuation. When data of HV and migraine patients were combined, the habituation slope of WD-VEP 1H was negatively correlated with that of TR-VEP N1-P1 and with number of days since the last migraine attack. CONCLUSION: These results are in favour of a migraine cycle-dependent imbalance between excitation and inhibition in the visual cortex. We hypothesize that an interictal hypoactivity of monaminergic pathways may cause a functional disconnection of the thalamus in migraine leading to an abnormal intracortical short-range lateral inhibition that could contribute to the habituation deficit observed during stimulus repetition

Alcohol-induced changes in conflict monitoring and error detection as predictors of alcohol use in late adolescence

Adolescence is a vulnerable period for the development of substance use and related problems. Understanding how exposure to drugs influences the adolescent brain could reveal mechanisms underlying risk for addiction later in life. In the current study, 87 adolescents (16-20-year olds; the local legal drinking age was16, allowing the inclusion of younger subjects than usually possible) underwent EEG measurements during a Go/No-Go task with and without alcohol cues; after placebo and a low dose of alcohol (0.45 g/kg). Conflict monitoring and error detection processes were investigated with the N2 and the error-related negativity (ERN) ERP components. Participants were followed-up after 6 months to assess changes in alcohol use. The NoGo-N2 was larger for alcohol cues and acute alcohol decreased the amplitude of the NoGo-N2 for alcohol cues. ERN amplitude was blunted for alcohol cues. Acute alcohol decreased the amplitude of the ERN, specifically for control cues. Furthermore, the differences in ERN for alcohol cues between the placebo and alcohol conditions predicted alcohol use 6 months later: subjects who showed stronger blunting of the ERN after acute alcohol were more likely to return to more moderate drinking patterns. These results suggest that cues signalling reward opportunities might activate a go-response mode and larger N2 (detection of increased conflict) for these cues might be necessary for inhibition. The ERN results suggest a deficiency in the monitoring system for alcohol cues. Finally, a lack of alcohol-induced deterioration of error monitoring for cues with high salience might be a vulnerability factor for alcohol abuse in adolescents