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16
Sequence of information processing for emotions based on the anatomic dialogue between prefrontal cortex and amygdala.
- Neuroimage
, 2007
"... The prefrontal cortex and the amygdala have synergistic roles in regulating purposive behavior, effected through bidirectional pathways. Here we investigated the largely unknown extent and laminar relationship of prefrontal input-output zones linked with the amygdala using neural tracers injected i ..."
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The prefrontal cortex and the amygdala have synergistic roles in regulating purposive behavior, effected through bidirectional pathways. Here we investigated the largely unknown extent and laminar relationship of prefrontal input-output zones linked with the amygdala using neural tracers injected in the amygdala in rhesus monkeys. Prefrontal areas varied vastly in their connections with the amygdala, with the densest connections found in posterior orbitofrontal and posterior medial cortices, and the sparsest in anterior lateral prefrontal areas, especially area 10. Prefrontal projection neurons directed to the amygdala originated in layer 5, but significant numbers were also found in layers 2 and 3 in posterior medial and orbitofrontal cortices. Amygdalar axonal terminations in prefrontal cortex were most frequently distributed in bilaminar bands in the superficial and deep layers, by columns spanning the entire cortical depth, and less frequently as small patches centered in the superficial or deep layers. Heavy terminations in layers 1-2 overlapped with calbindin-positive inhibitory neurons. A comparison of the relationship of input to output projections revealed that among the most heavily connected cortices, cingulate areas 25 and 24 issued comparatively more projections to the amygdala than they received, whereas caudal orbitofrontal areas were more receivers than senders. Further, there was a significant relationship between the proportion of 'feedforward' cortical projections from layers 2-3 to 'feedback' terminations innervating the superficial layers of prefrontal cortices. These findings indicate that the connections between prefrontal cortices and the amygdala follow similar patterns as corticocortical connections, and by analogy suggest pathways underlying the sequence of information processing for emotions.
Neurons in the basal forebrain project to the cortex in a complex topographic organization that reflects corticocortical connectivity patterns: an experimental study based on retrograde tracing and 3D reconstruction. Cereb. Cortex, doi:10.1093/cercor/bht2
, 2013
"... The most prominent feature of the Basal Forebrain (BF) is the collec-tion of large cortically projecting neurons (basal nucleus of Meynert) that serve as the primary source of cholinergic input to the entire cortical mantle. Despite its broad involvement in cortical activation, attention, and memory ..."
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The most prominent feature of the Basal Forebrain (BF) is the collec-tion of large cortically projecting neurons (basal nucleus of Meynert) that serve as the primary source of cholinergic input to the entire cortical mantle. Despite its broad involvement in cortical activation, attention, and memory, the functional details of the BF are not well understood due to the anatomical complexity of the region. This study tested the hypothesis that basalocortical connections reflect cortical connectivity patterns. Distinct retrograde tracers were de-posited into various frontal and posterior cortical areas, and retrogra-dely labeled cholinergic and noncholinergic neurons were mapped in the BF. Concurrently, we mapped retrogradely labeled cells in pos-terior cortical areas that project to various frontal areas, and all cell populations were combined in the same coordinate system. Our studies suggest that the cholinergic and noncholinergic projections to the neocortex are not diffuse, but instead, are organized into seg-regated or overlapping pools of projection neurons. The extent of overlap between BF populations projecting to the cortex depends on the degree of connectivity between the cortical targets of these pro-jection populations. We suggest that the organization of projections from the BF may enable parallel modulation of multiple groupings of interconnected yet nonadjacent cortical areas.
Specificity in Inhibitory Systems Associated with Prefrontal Pathways to Temporal Cortex in Primates
"... The prefrontal cortex selects relevant signals and suppresses irrelevant stimuli for a given task through mechanisms that are not understood. We addressed this issue using as a model system the pathways from the functionally distinct prefrontal areas 10 and 32 to auditory association cortex, and inv ..."
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The prefrontal cortex selects relevant signals and suppresses irrelevant stimuli for a given task through mechanisms that are not understood. We addressed this issue using as a model system the pathways from the functionally distinct prefrontal areas 10 and 32 to auditory association cortex, and investigated their relationship to inhibitory neurons labeled for calbindin (CB) or parvalbumin (PV), which differ in mode of inhibition. Projection neurons in area 10 originated mostly in layers 2--3 and were intermingled with CB inhibitory neurons. In contrast, projections from area 32 originated predominantly in layers 5--6 among PV inhibitory neurons. Prefrontal axonal boutons terminating in layers 2--3 of auditory association cortex were larger than those terminating in layer 1. Most pre-frontal axons synapsed on spines of excitatory neurons but a significant number targeted dendritic shafts of inhibitory neurons. Axons from area 10 targeted CB and PV inhibitory neurons, whereas axons from area 32 targeted PV inhibitory neurons. The preferential association of the 2 prefrontal pathways with distinct classes of inhibitory neurons at their origin and termination may reflect the specialization of area 10 in working memory functions and area 32 in emotional communication. These findings suggest diversity in inhibitory control by distinct prefrontal pathways.
Contrasting Patterns of Cortical Input to Architectural Subdivisions of the Area 8 Complex: A Retrograde Tracing Study in Marmoset Monkeys
"... Contemporary studies recognize 3 distinct cytoarchitectural and functional areas within the Brodmann area 8 complex, in the caudal prefrontal cortex: 8b, 8aD, and 8aV. Here, we report on the quantitative characteristics of the cortical projections to these areas, using injections of fluorescent trac ..."
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Contemporary studies recognize 3 distinct cytoarchitectural and functional areas within the Brodmann area 8 complex, in the caudal prefrontal cortex: 8b, 8aD, and 8aV. Here, we report on the quantitative characteristics of the cortical projections to these areas, using injections of fluorescent tracers in marmoset monkeys. Area 8b was distinct from both 8aD and 8aV due to its connections with medial prefrontal, anterior cingulate, superior temporal poly-sensory, and ventral midline/retrosplenial areas. In contrast, areas 8aD and 8aV received the bulk of the projections from posterior parietal cortex and dorsal midline areas. In the frontal lobe, area 8aV received projections primarily from ventrolateral areas, while both 8aD and 8b received dense inputs from areas on the dorsolat-eral surface. Whereas area 8aD received the most significant audi-tory projections, these were relatively sparse, in comparison with those previously reported in macaques. Finally, area 8aV was dis-tinct from both 8aD and 8b by virtue of its widespread input from the extrastriate visual areas. These results are compatible with a homologous organization of the prefrontal cortex in New and Old World monkeys, and suggest significant parallels between the present pathways, revealed by tract-tracing, and networks revealed by functional connectivity analysis in Old World monkeys and humans.
There’s Waldo! A Normalization Model of Visual Search Predicts Single-Trial Human Fixations in an Object Search Task
"... When searching for an object in a scene, how does the brain decide where to look next? Visual search theories suggest the existence of a global “priority map ” that integrates bottom-up visual information with top-down, target-specific signals. We propose amechanisticmodel of visual search that is c ..."
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When searching for an object in a scene, how does the brain decide where to look next? Visual search theories suggest the existence of a global “priority map ” that integrates bottom-up visual information with top-down, target-specific signals. We propose amechanisticmodel of visual search that is consistent with recent neurophysiological evidence, can localize targets in cluttered images, and predicts single-trial behavior in a search task. This model posits that a high-level retinotopic area selective for shape features receives global, target-specific modulation and implements local normalization through divisive inhibition. The normalization step is critical to prevent highly salient bottom-up features from monopolizing attention. The resulting activity pattern constitues a priority map that tracks the correlation between local input and target features. The maximum of this priority map is selected as the locus of attention. The visual input is then spatially enhanced around the selected location, allowing object-selective visual areas to determine whether the target is present at this location. This model can localize objects both in array images andwhen objects are pasted in natural scenes. Themodel can also predict single-trial human fixations, including those in error and target-absent trials, in a search task involving complex objects. Key words: computational modeling, normalization, object recognition, visual attention, visual search
Cognitive and Neural
"... The prefrontal cortex selects relevant signals and suppresses irrelevant stimuli for a given task through mechanisms that are not understood. We addressed this issue using as a model system the pathways from the functionally distinct prefrontal areas 10 and 32 to auditory association cortex, and inv ..."
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The prefrontal cortex selects relevant signals and suppresses irrelevant stimuli for a given task through mechanisms that are not understood. We addressed this issue using as a model system the pathways from the functionally distinct prefrontal areas 10 and 32 to auditory association cortex, and investigated their relationship to inhibitory neurons labeled for calbindin (CB) or parvalbumin (PV), which differ in mode of inhibition. Projection neurons in area 10 originated mostly in layers 2--3 and were intermingled with CB inhibitory neurons. In contrast, projections from area 32 originated predominantly in layers 5--6 among PV inhibitory neurons. Prefrontal axonal boutons terminating in layers 2--3 of auditory association cortex were larger than those terminating in layer 1. Most prefrontal axons synapsed on spines of excitatory neurons but a significant number targeted dendritic shafts of inhibitory neurons. Axons from area 10 targeted CB and PV inhibitory neurons, whereas axons from area 32 targeted PV inhibitory neurons. The preferential association of the 2 prefrontal pathways with distinct classes of inhibitory neurons at their origin and termination may reflect the specialization of area 10 in working memory functions and area 32 in emotional communication. These findings suggest diversity in inhibitory control by distinct prefrontal pathways.
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, 2009
"... doi: 10.3389/neuro.05.002.2009 Visual and motor connectivity and the distribution of calcium-binding proteins in macaque frontal eye field: implications for saccade target selection ..."
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doi: 10.3389/neuro.05.002.2009 Visual and motor connectivity and the distribution of calcium-binding proteins in macaque frontal eye field: implications for saccade target selection
Intracortical Augmenting Responses in Networks of Reduced Compartmental Models of Tufted Layer 5 Cells
, 2008
"... doi: 10.1152/jn.01280.2007 You might find this additional info useful... Supplementary material for this article can be found at: ..."
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doi: 10.1152/jn.01280.2007 You might find this additional info useful... Supplementary material for this article can be found at:
Edited by:
, 2009
"... doi: 10.3389/neuro.05.002.2009 Visual and motor connectivity and the distribution of calcium-binding proteins in macaque frontal eye field: implications for saccade target selection ..."
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doi: 10.3389/neuro.05.002.2009 Visual and motor connectivity and the distribution of calcium-binding proteins in macaque frontal eye field: implications for saccade target selection
Spike-field activity in parietal area LIP during coordinated reach and
, 2011
"... saccade movements ..."
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