https://surfer.nmr.mgh.harvard.edu/ftp/articles/dale99-recon1.pdf

Cortical surface-based analysis. I. Segmentation and surface reconstruction

https://surfer.nmr.mgh.harvard.edu/ftp/articles/fischl99b-recon2.pdf

Cortical Surface-Based Analysis II: Inflation, Flattening, and a Surface-Based Coordinate System

https://sites.oxy.edu/clint/physio/article/therewardcircuitlinkingprimateanatomyandhumanimaging.pdf

The reward circuit: linking primate anatomy and human imaging.

https://www.cogsci.ucsd.edu/~nunez/COGS160/Rizzolatti_Arbib_PS.pdf

Language within our grasp

This paper reviews architectonic subdivisions and connections of the orbital and medial prefrontal cortex (OMPFC) in rats, monkeys and humans. Cortico-cortical connections provide the basis for recognition of 'medial' and 'orbital' networks within the OMPFC. These networks also have distinct connections with structures in other parts of the brain. The orbital network receives sensory inputs from several modalities, including olfaction, taste, visceral afferents, somatic sensation and vision, which appear to be especially related to food or eating. In contrast, the medial network provides the major cortical output to visceromotor structures in the hypothalamus and brainstem. The two networks have distinct connections with areas of the striatum and mediodorsal thalamus. In particular, projections to the nucleus accumbens and the adjacent ventromedial caudate and putamen arise predominantly from the medial network. Both networks also have extensive connections with limbic structures. Based on these and other observations, the OMPFC appears to function as a sensory-visceromotor link, especially for eating. This linkage appears to be critical for the guidance of reward-related behavior and for setting of mood. Imaging and histological observations on human brains indicate that clinical depressive disorders are associated with specific functional and cellular changes in the OMPFC, including activity and volume changes, and specific changes in the number of glial cells.

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The Organization of Networks within the Orbital and Medial Prefrontal Cortex of Rats, Monkeys and Humans

Auditory cortex of macaque monkeys can be divided into a core of primary or primary-like areas located on the lower bank of the lateral sulcus, a surrounding narrow belt of associated fields, and a parabelt region just lateral to the belt on the superior temporal gyrus. We determined patterns of ipsilateral cortical connections of the parabelt region by placing injections of four to seven distinguishable tracers in each of five monkeys. Results were related to architectonic subdivisions of auditory cortex in brain sections cut parallel to the surface of artificially flattened cortex (four cases) or cut in the coronal plane (one case). An auditory core was clearly apparent in these sections as a 16- to 20-mm rostrocaudally elongated oval, several millimeters from the lip of the sulcus, that stained darkly for parvalbumin, myelin, and acetylcholinesterase. These features were most pronounced caudally in the cortex assigned to auditory area I, only slightly reduced in the rostral area, and most reduced in the narrower rostral extension we define as the rostrotemporal area. A narrow band of cortex surrounding the core stained more moderately for parvalbumin, acetylcholinesterase, and myelin. Two regions of the caudal belt, the caudomedial area, and the mediolateral area, stained more darkly, especially for parvalbumin. Rostromedial and medial rostrotemporal, regions of the medial belt stained more lightly for parvalbumin than the caudomedial area or the lateral belt. The parabelt region stained less darkly than the core and belt fields. Injections confined to the parabelt region labeled few neurons in the core, but large numbers in parts of the belt, the parabelt, and adjacent portions of the temporal lobe. Injections that encroached on the belt labeled large numbers of neurons in the core and helped define the width of the belt. Caudal injections in the parabelt labeled caudal portions of the belt, rostral injections labeled rostral portions, and both caudal and rostral injections labeled neurons in the rostromedial area of the medial belt. These observations support the concept of dividing the auditory cortex into core, belt, and parabelt; provide evidence for including the rostral area in the core; suggest the existence of as many as seven or eight belt fields; provide evidence for at least two subdivisions of the parabelt; and identify regions of the temporal lobe involved in auditory processing.

Subdivisions of Auditory Cortex and Ipsilateral Cortical Connections of the Parabelt Auditory Cortex in Macaque Monkeys

The ipsilateral cortical connections of primary motor cortex (M1) of owl monkeys were revealed by injecting WGA-HRP and fluorescent tracers into M1 sites identified by intracortical microstimulation. In some of the same animals, the extent and somatotopic organization of M1 was determined by making detailed microstimulation movement maps and relating the results to cortical architectonics. Thus, delineation of M1 was based on a combination of physiological and anatomical characteristics. M1 comprised most, but not all, of the cortex rostral to area 3a where movements were evoked at low levels of current (40 microA or less). Analysis of somatotopic patterns and architectonics placed some of the low-threshold sites in a ventral premotor field (PMV) and the dorsomedially situated supplementary motor area (SMA). Movements were also reliably elicited from a dorsal premotor area (PMD) at higher currents. M1 was characterized by a somatotopic global organization, representing hindlimb, trunk, forelimb, and face movements in a mediolateral sequence, and a mosaic local organization, with a given movement typically represented at several different sites. Architectonically, M1 was characterized by the absence of a granular layer IV and the presence of very large layer V pyramidal cells. However, M1 was not uniform in structure: pyramidal cells were larger caudally than rostrally, a feature we used to distinguish caudal (M1c) and rostral (M1r) subdivisions of the area. M1 resembles Brodmann's area 4, although the rostral subdivision has probably been considered as part of area 6 by some workers. Tracer injections of M1 revealed somatotopically distributed connections with motor areas PMD, PMV, and SMA, as well as in somatosensory areas 3a, 1, 2, and S2. Weaker connections were with area 3b, posterior parietal cortex, the parietal ventral area (PV), and cingulate cortex. M1r and M1c differed connectionally as well as architectonically, M1c being connected primarily with somatosensory areas, while M1r was strongly connected with both non-primary motor cortex and somatosensory cortex. These results indicate that M1 interacts directly with at least three non-primary motor areas and at least six somatosensory areas.

Architectonics, somatotopic organization, and ipsilateral cortical connections of the primary motor area (M1) of owl monkeys.

Prefrontal connections of the parabelt auditory cortex in macaque monkeys

We used intracortical microstimulation to investigate the lateral premotor cortex and neighboring areas in 14 hemispheres of owl monkeys, focusing on the somatotopic distribution of evoked movements, thresholds for forelimb movements, and the relative representation of proximal and distal forelimb movements. We elicited movements from the dorsal and ventral premotor areas (PMD, PMV), the caudal and rostral divisions of primary motor cortex (Mlc, Mlr), the frontal eye field (FEF), the dorsal oculomotor area (OMD; area 8b), the supplementary motor area (SMA), and somatosensory cortex (areas 3a and 3b). Area PMD was composed of architectonically distinguishable caudal and rostral subdivisions (PMDc, PMDr). Stimulation of PMD elicited movements of the hindlimb, forelimb, neck and upper trunk, face, and eyes. Hindlimb and forelimb movements were represented in the caudalmost part of PMDc. Face, neck, and eye movements were represented in the lateral and rostral parts of PMDc and in PMDr. Stimulation of PMV elicited forelimb and orofacial movements, but not hindlimb movements. Both proximal and distal forelimb movements were elicited from PMDc and PMV, although PMD stimulation elicited mainly shoulder and elbow movements, while PMV stimulation evoked primarily wrist and digit movements. Distal movements were evoked more frequently from PMV than from Mlr or Mlc. Across cases, the median forelimb thresholds for PMDc and PMV were 60 and 36 μA, respectively, values that differ significantly from each other and from the value of 11 μA obtained for Mlr. Our observations indicate that premotor cortex is much more responsive to electrical stimulation than commonly thought, and contains a large territory from which eye movements can be elicited. These results suggest that in humans, much of the electrically excitable cortex located on the precentral gyrus, including cortex sometimes considered part of the frontal eye field, is probably homologous to the premotor cortex of nonhuman primates. © 1996 Wiley-Liss, Inc.

Movement representation in the dorsal and ventral premotor areas of owl monkeys: a microstimulation study.

The auditory cortex of macaque monkeys contains a core of primary-like areas surrounded by a narrow belt of associated fields that encompass much of the superior temporal plane in these animals. Adjacent to the lateral belt on the superior temporal gyrus is a parabelt region that contains at least two subdivisions (rostral and caudal). In a previous study (Hackett et al. [1998] J. Comp. Neurol. 394:475–495), we determined that the parabelt has topographic connections with the belt areas surrounding the core, but minimal connections with the core itself. In this study, we describe the thalamocortical connections of the parabelt auditory cortex based on multiple injections of neuronal tracers into this region in each of five macaque monkeys. Injections confined to the parabelt labeled large numbers of neurons in the dorsal (MGd) and magnocellular (MGm) divisions of the medial geniculate complex (MGC), suprageniculate (Sg), limitans (Lim), and medial pulvinar (PM) nuclei. Only when injections encroached on the lateral belt cortex were substantial numbers of labeled neurons found in the ventral (MGv) division of the MGC, consistent with the absence of significant connections between the parabelt and core fields. The rostrocaudal topography of the parabelt region was maintained in the thalamocortical connections, supporting the parcellation of this region of cortex. The results suggest that the parabelt region represents a third level of auditory cortical processing, which is not influenced by direct inputs from primary cortical or subcortical auditory structures. J. Comp. Neurol. 400:271–286, 1998. © 1998 Wiley-Liss, Inc.

Iwona Stepniewska

Papers

Subdivisions of Auditory Cortex and Ipsilateral Cortical Connections of the Parabelt Auditory Cortex in Macaque Monkeys

Architectonics, somatotopic organization, and ipsilateral cortical connections of the primary motor area (M1) of owl monkeys.

Prefrontal connections of the parabelt auditory cortex in macaque monkeys

Movement representation in the dorsal and ventral premotor areas of owl monkeys: a microstimulation study.

Thalamocortical connections of the parabelt auditory cortex in macaque monkeys