Julia A. M. Delius

Lucifer yellow filling of immunohistochemically pre-labeled neurons: a new method to characterize neuronal subpopulations.

We describe a new technique for the morphological characterization of immunohistochemically labeled neuron populations. We demonstrate that it is possible to fill neurons iontophoretically with Lucifer Yellow (LY) in fixed slices of cat visual cortex after the respective cells have been identified by indirect immunofluorescence for the neural cell adhesion molecule N-CAM 180, with the VC1.1 antibody or with an antibody against glutamate dehydrogenase (GAD). Morphological analysis of the injected cells at the light and electron microscopic level revealed that the N-CAM 180-positive neurons share the features of neuropeptidergic cortical interneurons. Depending on the antibody applied, the immunohistochemical treatment had little or no noticeable effect on the quality of LY filling or on the preservation of morphological details of the pre-labeled cells. This makes the method described ideally suited for the light and electron microscopic examination of selected, immunologically characterized neuron subpopulations.

NCAM 180 IN THE POSTNATAL DEVELOPMENT OF CAT VISUAL CORTEX : AN IMMUNOHISTOCHEMICAL STUDY

The neural cell adhesion molecule (NCAM) consists of three major isoforms with differing extents of intracellular domains. The largest, NCAM 180, may play an important role in the development and stabilization of cell contacts because of its interaction with the cytoskeleton, its accumulation at contact sites between cells, and age‐dependent modifications of the immunoreactivity of its intracellular domain. The developmental expression pattern of NCAM 180 was examined in the cat visual cortex to explore its relation with the age‐dependent decline of synaptic malleability. Western blot and immunohistochemical analyses were carried out by using a monoclonal antibody (D3) directed against an epitope of the intracellular domain specific to NCAM 180 and antibodies against all NCAM isoforms. The latter revealed a similar time course of increased expression during development by both Western blot and immunohistochemical analysis. In contrast, the D3 antibody showed an age‐dependent increase of immunoreactivity by Western blot analysis and a decrease of reactivity by immunohistochemistry. In addition, the D3 antibody revealed characteristic developmental changes of immunoreactivity in the neuropil and distribution of immunopositive neuronal cell bodies in the different cortical laminae. The observations from this and another study (Kramer et al., 1997) suggest that the D3 antibody‐specific NCAM 180 epitope is masked during the stabilization of connectivity. J. Neurosci. Res. 49:255–267, 1997.

Berlin Aging Studies (BASE and BASE-II)

The Berlin Aging Studies (BASE and BASE-II) are two consecutive studies of old age and aging with an interdisciplinary focus. The disciplines involved include psychology, psychiatry, geriatrics and internal medicine, genetics, sociology, and economics. The initial BASE data collection involved 14 sessions and took place in 1990–1993with 516men and women aged 70 to over 100 years. BASE-II currently involves five sessions with 1,600 older adults aged 60–80 years as well as 600 younger adults aged 20–35 years, who were assessed for the first time in 2011–2014. The initial Berlin Aging Study (BASE) was launched in 1989. In 1990–1993, 516 women and men aged 70 to 100+ years and living in the former West Berlin completed an intensive protocol of 14 sessions that exhaustively assessed their physical and mental health, life histories, living conditions, and psychological status. Subsequently, seven longitudinal follow-up assessments of surviving participants who had agreed to take part again were carried out until 2008/2009. In addition, mortality information was obtained regularly from the city registry. This allowed the examination of ageand death-related changes in old age. In 2011, a new study was launched, the Berlin Aging Study II (BASE-II), which focuses on many of the constructs examined in BASE as well as new constructs, but follows a larger group of old participants as well as a group of young adults for comparison. In the following, BASE and BASE-II are presented in depth, first focusing on BASE, and then drawing attention to select features of BASE-II.

Complex networks emerging during choir singing: Complex networks during choir singing

Choir singing is positively associated with well‐being and quality of life, and requires the coordination of physiological systems within and across individuals. Informed by models of interpersonal action coordination, we delineate the network topography of choir singing by analyzing cross‐frequency couplings and within‐frequency couplings (WFCs) of respiratory, cardiac, vocalizing, and motor subsystems. We find that respiratory and cardiac subsystems synchronize with one another during singing and are coupled to oscillatory vocalizing patterns, and to the hand‐movement oscillations of the choirs conductor. The choirs cross‐frequency connections are particularly strong when singing a canon in parts, apparently supporting the interaction and coordination of the different canon entries. In contrast, WFCs are more pronounced when singing the same canon in unison. We conclude that the temporal coordination dynamics of the observed subsystems form part of the functional substrate for choir singing. During singing, the choir functions as a superordinate system, or superorganism, that imposes boundary conditions on the dynamic features of the individual singers.

Symmetry recognition by pigeons: Generalized or not?

This note looks into the reasons why earlier reports may have arrived at differing conclusions about pigeons’ capacity to categorize bilaterally symmetric and asymmetric visual patterns. Attention is drawn to pigeons’ comparatively superior visual flicker resolution and superior visual linear acuity by reporting results of two ad-hoc experiments. This circumstance turns out to constrain conclusions drawn by earlier symmetry–asymmetry studies that used computer-generated patterns displayed on cathode ray tube monitors as these suffered from pictorial distortions. Additionally one of the studies involved patterns of inconsistent symmetry at global and local levels. A smaller-scale experiment using slide-projected unequivocal symmetric and asymmetric patterns yielded results compatible with the supposition that pigeons are capable of a symmetry–asymmetry categorization. The possibility that an artfactual cue may have inadvertently accentuated this capability in an earlier own experiment is considered.