To identify zinc-containing projections to the visual areas, we injected Fluoro-Gold into the occipital cortex of the mouse. Five days later, the mice underwent an intravital selenium-labeling procedure to demonstrate the somata of neurons that give rise to zinc-containing boutons. Numerous double-labeled cells were seen in the ipsi-and contralateral primary (layers II/III and VI), and secondary visual cortices (layers II/III and VI). A few double-labeled cells were apparent in other cortical areas concerned with visual processing: the orbital cortex (layers II and III), the posterior portion of the medial agranular frontal cortex (layer V/VI border), and the temporal cortex (layer VI). The cingulate, retrosplenial, perirhinal, and lateral entorhinal cortices had lamina projecting to the visual cortex and separate lamina harboring zinc-containing cells. A spatial segregation of fluorescent and zinc-containing neurons was also seen in the claustrum. This integration or segregation of projecting and zinc-containing neurons may reflect the function of the cortical areas. N-methyl-D-aspartate receptor function is antagonized by physiological concentrations of zinc in vitro. It is proposed that zinc-positive projections from areas that perform basic visual functions are less likely to be modified by N-methyl-D-aspartate receptor-mediated processes than the zinc-negative connections from associational areas.

This study reports on the development and assessment of a new 30-item Multidimensional Language Class Anxiety Scale which is designed to assess foreign language learners’ anxiety regarding four language skills (listening, reading, writing, and speaking) and testing. In Study 1, the initial items were piloted with 323 students studying English as a foreign language at three different universities in Turkey. This informed a revised version of the questionnaire which was subsequently administered to 701 students at three different Turkish universities. Confirmatory factor analyses revealed that a bifactor model with correlated residual variance yielded a better fit for the data in both studies than the other four models tested. The overall results provided preliminary evidence for the reliability and validity of the data collected using the new scale. Directions for future research and implications for foreign language teaching and learning are discussed.

The postnatal development of zinc-containing synaptic boutons and their cells of origin in the visual cortex of a pigmented mouse is described. Two phases can be distinguished. During the early phase zinc-containing neuropil is first apparent by postnatal day 3. By day 7 a light, but distinct neuropil staining sketches the primary and secondary visual cortices. The primary visual area contains light precipitate in layers V and VI as well as the monocular portion of layer II/III. The secondary visual areas contain slightly denser precipitate in layers II/III through VI. The transition to the second phase is marked by a large increase in precipitate density by day 11. Thereafter, the intensity of the neuropil staining increases to day 28, first in layer II/III and then in layer V, as the adult pattern of neuropil staining gradually develops. In the primary visual cortex precipitate is dense in layers II/III and V, moderate in layer VI, and sparse in layers I and IV. In the secondary visual areas the precipitate is dense in layers II/III and V and moderate in the lower portion of layer I and in layers IV and VI. Cells of origin of zinc-containing boutons are visible by the end of the second postnatal week in layer II/III of the secondary visual cortex. By 21 days of age the pattern of staining in the mature mouse is established, and cells in layers II/III and VI are labeled in both the primary and secondary visual cortices. The developmental sequence of zinc-containing cells and neuropil does not preclude an involvement of zinc in the postnatal regulation of NMDA receptor function.

The distributions of acetylcholinesterase (AChE) and zinc-containing boutons and their cells of origin in the visual cortex of the house mouse (Mus musculus domesticus) are described. The primary visual area is defined by both acetylcholinesterase and zinc staining. The AChE staining pattern is dark in upper layer I and layers IV and VI. It is light in layers II/III and V. The lack of a densely stained layer IV in the secondary visual cortices defines the borders between primary and secondary areas. Large, multipolar AChE-positive neurons are located throughout the cortical layers, but preferentially in layer VI. Dense zinc-positive neuropil in the primary visual cortex is apparent in layer Ib, upper layer II/III, and layers V and VI. Neurons that give rise to zinc-containing boutons are situated in layers II/III and VI. The medial and lateral borders can be distinguished by a bold contrast of staining in lower layer II/III; the secondary areas have more zinc-positive neurons, and the neuropil stains darker. A surprising observation of this study is the disparity between the mouse and rat visual cortex of the AChE staining pattern. Layer V is very light in the mouse, whereas a dark stain has been described in layer V of the rat. Layer VI stains heavily in the mouse while less AChE activity has been observed in layer VI of the rat.

Cytoarchitecture and distributions of acetylcholinesterase-containing fibers and zinc-containing neuropil are described in the primary visual cortex of a metatherian, the Parma wallaby (Macropus parma). Although some cytoarchitectural features of layer III suggest that a subdivision and a corresponding layer IIIa-c terminology may be employed, neurochemistry is more concisely described using a simple layer I-VI terminology. Horizontal acetylcholinesterase-containing fibers in layer I take on a vertical course as they pass through layer II to form a reticulate pattern in upper layer III. Fibers gather into vertical groups in lower layer III and, markedly, in layer IV. No dominant orientation is seen in layer V, whereas an horizontal course is often seen in layer VI. Zinc-containing neuropil is very dense in layers I, II and upper III, where particles are homogeneously distributed. Particles begin to form strands in lower layer III and form conspicuous vertical clusters in an otherwise almost unstained layer IV. There is a sharp transition to a densely and homogeneously stained layer V, a decrease in staining intensity in layer VI, and a further decrease within layer VI towards the white matter. The distribution of acetylcholinesterase-containing fibers in M. parma, a metatherian representative, adds to the number of species-specific patterns observed in eutherians. The distribution of zinc-containing neuropil in M. parma resembles the consistent pattern seen in eutherian species. Thus, pathways incorporating zinc, as a putative neuromodulator of excitatory amino acid receptor responses, may be organized similarly in the cortex of meta- and eutherians.