Restoring wild-type-like CA1 network dynamics and behavior during adulthood in a mouse model of schizophrenia.

Schizophrenia is a severely debilitating neurodevelopmental disorder. Establishing a causal link between circuit dysfunction and particular behavioral traits that are relevant to schizophrenia is crucial to shed new light on the mechanisms underlying the pathology. We studied an animal model of the human 22q11 deletion syndrome, the mutation that represents the highest genetic risk of developing schizophrenia.

Sorting Overlapping Spike Waveforms from Electrode and Tetrode Recordings.

One of the outstanding problems in the sorting of neuronal spike trains is the resolution of overlapping spikes. Resolving these spikes can significantly improve a range of analyses, such as response variability, correlation, and latency. In this paper, we describe a partially automated method that is capable of resolving overlapping spikes.

Methods, caveats and the future of large-scale microelectrode recordings in the non-human primate.

Cognitive processes play out on massive brain-wide networks, which produce widely distributed patterns of activity. Capturing these activity patterns requires tools that are able to simultaneously measure activity from many distributed sites with high spatiotemporal resolution. Unfortunately, current techniques with adequate coverage do not provide the requisite spatiotemporal resolution.

Frontoparietal correlation dynamics reveal interplay between integration and segregation during visual working memory.

Working memory requires large-scale cooperation among widespread cortical and subcortical brain regions. Importantly, these processes must achieve an appropriate balance between functional integration and segregation, which are thought to be mediated by task-dependent spatiotemporal patterns of correlated activity. Here, we used cross-correlation analysis to estimate the incidence, magnitude, and relative phase angle of temporally correlated activity from simultaneous local field potential recordings in a network of prefrontal and posterior parietal cortical areas in monkeys performing an oculomotor, delayed match-to-sample task.

Performance evaluation of collision-reaction interface and internal standardization in quadrupole ICP-MS measurements.

The combined use of internal standardization with collision and reaction interface in an inductively coupled plasma quadrupole mass spectrometer (ICP-QMS-CRI) was evaluated. The behavior of several elements (Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Pb, Sb, V and Zn) was studied by introducing H(2) or He through the skimmer and sampler cones of the CRI device and by using In, Rh and Sc as internal standards. Certified reference material of trace elements in water (NIST 1643e) was used to evaluate the performance of the method.

Modulation of synchrony without changes in firing rates.

It was often reported and suggested that the synchronization of spikes can occur without changes in the firing rate. However, few theoretical studies have tested its mechanistic validity. In the present study, we investigate whether changes in synaptic weights can induce an independent modulation of synchrony while the firing rate remains constant.

Directed interactions between visual areas and their role in processing image structure and expectancy.

During sensory processing, cortical areas continuously exchange information in different directions along the hierarchy. The functional role of such interactions, however, has been the subject of various proposals. Here, we investigate the role of bottom-up and top-down interactions in processing stimulus structure and their relation to expected events.

NMDA lesions in the medial prefrontal cortex impair the ability to inhibit responses during reversal of a simple spatial discrimination.

Although lesion studies suggest that the rat medial prefrontal cortex (mPFc) is involved in the process necessary for reversal of a particular set of contingencies, the nature of lesion-induced deficits is unclear. The involvement of rat mPFc in reversal of a simple spatial discrimination was examined in the present study. Our hypothesis was that lesion-induced deficits may reflect a failure to inhibit a learned instrumental response.

Effects of training on neuronal activity and interactions in primary and higher visual cortices in the alert cat.

The effects of behavioral training on early visual representations have been elusive when assessed with firing rates. Learning-induced changes in performance, however, suggest that representations should encompass early cortical stages. Here, we address the question of whether training-induced effects are pertinent to neuronal activity outside the task proper, which is a requirement if subsequent perceptional processes should profit from training.

Responses to natural scenes in cat V1.

Studies on processing in primary visual areas often use artificial stimuli such as bars or gratings. As a result, little is known about the properties of activity patterns for the natural stimuli processed by the visual system on a daily basis. Furthermore, in the cat, a well-studied model system for visual processing, most results are obtained from anesthetized subjects and little is known about neuronal activations in the alert animal.