Article

Architecture and neurocytology of monkey cingulate gyrus

Harvard University, Cambridge, Massachusetts, United States
The Journal of Comparative Neurology (Impact Factor: 3.23). 05/2005; 485(3):218-39. DOI: 10.1002/cne.20512
Source: PubMed

ABSTRACT

Human functional imaging and neurocytology have produced important revisions to the organization of the cingulate gyrus and demonstrate four structure/function regions: anterior, midcingulate (MCC), posterior (PCC), and retrosplenial. This study evaluates the brain of a rhesus and 11 cynomolgus monkeys with Nissl staining and immunohistochemistry for neuron-specific nuclear binding protein, intermediate neurofilament proteins, and parvalbumin. The MCC region was identified along with its two subdivisions (a24' and p24'). The transition between areas 24 and 23 does not involve a simple increase in the number of neurons in layer IV but includes an increase in neuron density in layer Va of p24', a dysgranular layer IV in area 23d, granular area 23, with a neuron-dense layer Va and area 31. Each area on the dorsal bank of the cingulate gyrus has an extension around the fundus of the cingulate sulcus (f 24c, f 24c', f 24d, f 23c), whereas most cortex on the dorsal bank is composed of frontal motor areas. The PCC is composed of a dysgranular area 23d, area 23c in the caudal cingulate sulcus, a dorsal cingulate gyral area 23a/b, and a ventral area 23a/b. Finally, a dysgranular transition zone includes both area 23d and retrosplenial area 30. The distribution of areas was plotted onto flat maps to show the extent of each and their relationships to the vertical plane at the anterior commissure, corpus callosum, and cingulate sulcus. This major revision of the architectural organization of monkey cingulate cortex provides a new context for connection studies and for devising models of neuron diseases.

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    • "A consequence is that the majority of prefrontal areas is numbered (Walker 1940) but has often been further subdivided using letters that often help to locate the subarea (Carmichael and Price 1994). The letter " r " refers to rostral (areas 14r and 12r) whereas " c " refers to caudal (area 14c), except for area 24, which has traditionally been divided into areas 24a, 24b, and 24c, going increasingly dorsal above the corpus callosum (Vogt et al. 2005). The letter " m " refers to medial (areas 9m, 10m, 11m, 12m, and 13m) whereas " l " refers to lateral (areas 9l, 11l, 12l, and 13l). "
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    ABSTRACT: The projections from the amygdala and hippocampus (including subiculum and presubiculum) to prefrontal cortex were compared using anterograde tracers injected into macaque monkeys (Macaca fascicularis, Macaca mulatta). Almost all prefrontal areas were found to receive some amygdala inputs. These connections, which predominantly arose from the intermediate and magnocellular basal nucleus, were particularly dense in parts of the medial and orbital prefrontal cortex. Contralateral inputs were not, however, observed. The hippocampal projections to prefrontal areas were far more restricted, being confined to the ipsilateral medial and orbital prefrontal cortex (within areas 11, 13, 14, 24a, 32, and 25). These hippocampal projections principally arose from the subiculum, with the fornix providing the sole route. Thus, while the lateral prefrontal cortex essentially receives only amygdala inputs, the orbital prefrontal cortex receives both amygdala and hippocampal inputs, though these typically target different areas. Only in medial prefrontal cortex do direct inputs from both structures terminate in common sites. But, even when convergence occurs within an area, the projections predominantly terminate in different lamina (hippocampal inputs to layer III and amygdala inputs to layers I, II, and VI). The resulting segregation of prefrontal inputs could enable the parallel processing of different information types in prefrontal cortex. © The Author 2015. Published by Oxford University Press.
    Full-text · Article · Feb 2015 · Cerebral Cortex
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    • ". © Cambridge University Press 2014 doi:10.1017/S0033291714000348 OR I G I N A L A R T I C L E heterogeneous structure in terms of function, receptor architecture and cytology (Vogt et al. 2005; Palomero- Gallagher et al. 2008; Pizzagalli, 2011), and has been subdivided into a more dorsal portion (dorsal ACC; dACC) and a more ventral subregion, the latter of which has been further divided into the rostral ACC (rACC; also referred to as the 'pregenual' or 'perigenual' ACC) and the subgenual ACC (sgACC; Etkin et al. 2011). Broadly speaking, a distinction may be made between the more 'cognitive' dACC versus the more 'affective' ventral subdivision encompassing the rACC and sgACC. "

    Full-text · Dataset · Jan 2015
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    • ". © Cambridge University Press 2014 doi:10.1017/S0033291714000348 OR I G I N A L A R T I C L E heterogeneous structure in terms of function, receptor architecture and cytology (Vogt et al. 2005; Palomero- Gallagher et al. 2008; Pizzagalli, 2011), and has been subdivided into a more dorsal portion (dorsal ACC; dACC) and a more ventral subregion, the latter of which has been further divided into the rostral ACC (rACC; also referred to as the 'pregenual' or 'perigenual' ACC) and the subgenual ACC (sgACC; Etkin et al. 2011). Broadly speaking, a distinction may be made between the more 'cognitive' dACC versus the more 'affective' ventral subdivision encompassing the rACC and sgACC. "
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    ABSTRACT: Background: Studies investigating structural brain abnormalities in depression have typically employed a categorical rather than dimensional approach to depression (i.e., comparing subjects with DSM-defined Major Depressive Disorder [MDD] vs. healthy controls). The National Institute of Mental Health (NIMH), through their Research Domain Criteria (RDoC) initiative, has encouraged a dimensional approach to the study of psychopathology as opposed to an overreliance on categorical (e.g., DSM-based) diagnostic approaches. Moreover, subthreshold levels of depressive symptoms (i.e., severity levels below DSM criteria) have been found to be associated with a range of negative outcomes, yet have been relatively neglected in neuroimaging research. Methods: To examine the extent to which depressive symptoms - even at subclinical levels - are linearly related to gray matter volume reductions in theoretically important brain regions, we employed whole-brain voxel-based morphometry (VBM) in a sample of 54 participants. Results: The severity of mild depressive symptoms, even in a subclinical population, was associated with reduced gray matter volume in the orbitofrontal cortex, anterior cingulate, thalamus, superior temporal gyrus/temporal pole and superior frontal gyrus. A conjunction analysis revealed concordance across two separate measures of depression. Conclusions: Reduced gray matter volume in theoretically important brain regions can be observed even in a sample that does not meet DSM criteria for MDD, but who nevertheless report relatively elevated levels of depressive symptoms. Overall, these findings highlight the need for additional research using dimensional conceptual and analytic approaches, as well as further investigation of subclinical populations.
    Full-text · Article · Mar 2014 · Psychological Medicine
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