Letter from the Editorial Board

Letter from the Editorial Boar

Letter from the editorial board

Letter from the editorial board of MSJP

Letter from the Editorial Board

Letter from the Editorial Board of the MSJP

Learning-induced neural plasticity of speech processing before birth

Peer reviewe

Newborns discriminate novel from harmonic sounds: a study using magnetoencephalography

Objective: We investigated whether newborns respond differently to novel and deviant sounds during quiet sleep. Methods: Twelve healthy neonates were presented with a three-stimulus oddball paradigm, consisting of frequent standard (76%), infrequent deviant (12%), and infrequent novel stimuli (12%). The standards and deviants were counterbalanced between the newborns and consisted of 500 and 750 Hz tones with two upper harmonics. The novel stimuli contained animal, human, and mechanical sounds. All stimuli had a duration of 300 ms and the stimulus onset asynchrony was 1 s. Evoked magnetic responses during quiet sleep were recorded and averaged offline. Results: Two deflections peaking at 345 and 615 ms after stimulus onset were observed in the evoked responses of most of the newborns. The first deflection was larger to novel and deviant stimuli than to the standard and, furthermore, larger to novel than to deviant stimuli. The second deflection was larger to novel and deviant stimuli than to standards, but did not differ between the novels and deviants. Conclusions: The two deflections found in the present study reflect different mechanisms of auditory change detection and discriminative processes. Significance: The early brain indicators of novelty detection may be crucial in assessing the normal and abnormal cortical function in newborns. Further, studying evoked magnetic fields to complex auditory stimulation in healthy newborns is needed for studying the newborns at-risk for cognitive or language problems

Electrophysiology:From molecule to cognition, from animal to human

Electrophysiology is the field of study that examines physiological signals of the brain. It ranges from assessment of molecular activity using patch clamp techniques to population measurements such as electroencephalography (EEG). This chapter deals with those methods and their role in drug discovery. The on-cell patch is the most widely used patch clamp technique, which measures the activity of one ion in a community of intracellular ions. Single-cell recordings are done to assess changes in action potentials, the output of a system. Intracranial electrodes can also be used to detect activity from multiple or populations of neurons. Depending on how the signal is filtered, indirect action potentials (i.e., output from a region) or postsynaptic signals (i.e., input to a region) are detected. A final type of measurement described in this chapter is EEG. The measured signal, obtained from the scalp, is similar to that obtained from local field potentials that are recorded intracranially. EEG measured in humans has frequently been compared to local field potentials recorded from living animals, showing a number of similarities between species. However, due to genetic or anatomical differences, in combination with differing electrode locations, it is still unclear how comparable the signals are. Future research should try to optimize animal methodology to increase the translational potential

EEG Correlates of Old/New Discrimination Performance Involving Abstract Figures and Non-Words

The processing of pre-experimentally unfamiliar stimuli such as abstract figures and non-words is poorly understood. Here, we considered the role of memory strength in the discrimination process of such stimuli using a three-phase old/new recognition memory paradigm. Memory strength was manipulated as a function of the levels of processing (deep vs. shallow) and repetition. Behavioral results were matched to brain responses using EEG. We found that correct identification of the new abstract figures and non-words was superior to old item recognition when they were merely studied without repetition, but not when they were semantically processed or drawn. EEG results indicated that successful new item identification was marked by a combination of the absence of familiarity (N400) and recollection (P600) for the studied figures. For both the abstract figures and the non-words, the parietal P600 was found to differentiate between the old and new items (late old/new effects). The present study extends current knowledge on the processing of pre-experimentally unfamiliar figurative and verbal stimuli by showing that their discrimination depends on experimentally induced memory strength and that the underlying brain processes differ. Nevertheless, the P600, similar to pre-experimentally familiar figures and words, likely reflects improved recognition memory of meaningless pictorial and verbal items.</p

Biperiden Selectively Impairs Verbal Episodic Memory in a Dose- and Time-Dependent Manner in Healthy Subjects

Purpose/Background: Biperiden is a muscarinic antagonist that produces memory impairments without impairing attention or motor functions in healthy subjects. It has been suggested that a biperiden-induced memory deficit could model age- and dementia-related memory impairments. The goal of the current study was to determine the dose- and time-dependent effects of biperiden on cognition in healthy volunteers. Methods/Procedures: Twenty-one healthy volunteers participated in a placebo-controlled, 3-way, crossover study. After a baseline test, cognitive performance was tested at 3 time points after a single dose of biperiden 2 or 4 mg, or placebo. Episodic memory was measured using a 15-word verbal learning task (VLT). Furthermore, n-back tasks, a sustained attention to response task and a reaction time task were used, as well as subjective alertness and a side effects questionnaire. In addition, blood serum values and physiological measures were taken. Findings/Results: Biperiden decreased the number of words recalled in immediate and delayed recall of the VLT 90 minutes after drug intake. A dose-dependent impairment was found for the delayed recall, whereas the immediate recall was equally impaired by the 2 doses. Biperiden did not affect the performance on the VLT 4 hours after administration. Performance in the n-back task and the sustained attention to response task were not affected by biperiden at any time point. Both doses were well tolerated as reported side effects were mild at Tmax and were minimal at the other time points. Implications/Conclusions: Biperiden exerts effects on episodic memory without negatively affecting other cognitive performance and behavioral measures that were assessed in this study. The data provide further evidence that biperiden has selective effects on cognition, even after a high dose