Prefrontal Projections to the Thalamic Reticular Nucleus form a Unique Circuit for Attentional Mechanisms

Zikopoulos, Basilis; Barbas, Helen

doi:10.1523/jneurosci.5511-05.2006

Cited by 297 publications

(299 citation statements)

References 96 publications

(115 reference statements)

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“…We associate this nonspecific inhibition with spatial attention directed toward the receptive field containing both the target and the distractor; we assume that it affects nearby, but not distant, receptive fields. Such nonspecific inhibition could be activated via the thalamus (27), via inhibitory systems associated with direct prefrontal pathways (28), or by localized modulation arising from basal forebrain cholinergic projections (29). Our assumptions are consistent with data suggesting that the spatial extent of focal attention in V4 can be as small as a receptive field (30); data from MT suggest that attention can even select subregions of the receptive field (31).…”

Section: Resultssupporting

confidence: 82%

Gamma oscillations mediate stimulus competition and attentional selection in a cortical network model

Börgers

Epstein

Kopell

2008

Proc. Natl. Acad. Sci. U.S.A.

153

158

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Simultaneous presentation of multiple stimuli can reduce the firing rates of neurons in extrastriate visual cortex below the rate elicited by a single preferred stimulus. We describe computational results suggesting how this remarkable effect may arise from strong excitatory drive to a substantial local population of fast-spiking inhibitory interneurons, which can lead to a loss of coherence in that population and thereby raise the effectiveness of inhibition. We propose that in attentional states fast-spiking interneurons may be subject to a bath of inhibition resulting from cholinergic activation of a second class of inhibitory interneurons, restoring conditions needed for gamma rhythmicity. Oscillations and coherence are emergent features, not assumptions, in our model. The gamma oscillations in turn support stimulus competition. The mechanism is a form of ''oscillatory selection,'' in which neural interactions change phase relationships that regulate firing rates, and attention shapes those neural interactions.cholinergic modulation ͉ selective attention ͉ gamma rhythm C ortical gamma frequency (30-90 Hz) oscillations are known to be associated with many aspects of cognition, including sensory processing, attention, memory, and awareness (1). However, the biophysical underpinnings of gamma oscillations and the means by which they contribute to cognitive processing are still not fully understood. Here we continue a series of computational studies investigating how the biophysics of the gamma rhythm, and in particular its neuromodulation, affect network processing associated with attention (2-4).We focus on the much-cited experiments of Desimone and colleagues (5-7). These showed that orientation-selective principal neurons in macaque V2 and V4 respond to simultaneous presentation of preferred (''good'') and nonpreferred (''poor'') stimuli in their receptive fields at spike rates well below those elicited by the preferred stimulus alone. Furthermore, when attention is directed to either of the two stimuli, the neuron responds almost as if the unattended stimulus were absent.The essence of the mechanism we propose here is a relationship between the effectiveness of the excitatory inputs to the target network and the coherence of the network's inhibitory cells: The same drive that produces a robust response when the inhibition is coherent produces a much less robust response when the inhibition is incoherent. We describe how this mechanism can, qualitatively at least, explain the results in (5-7).Selective attention is associated with an increase in coherence of spiking and in spectral power of oscillations in the gamma frequency band (8-10). The model we offer here does not assume a priori that bottom-up or top-down input is made more coherent or more oscillatory as a result of attention (11,12). Rather, the increased gamma power and coherence of the network output are consequences of the biophysical effects of cholinergic modulation. A critical feature of the model is that the target entity of competing stream...

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Section: Resultssupporting

confidence: 82%

Gamma oscillations mediate stimulus competition and attentional selection in a cortical network model

Börgers

Epstein

Kopell

2008

Proc. Natl. Acad. Sci. U.S.A.

153

158

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“…Attentional modulation of visceromotor prediction errors, which influences the balance of precision weights between priors and prediction errors, is thought to be implemented by gain mechanisms in the anterior insula and anterior cingulate cortex (Corbetta and Shulman, 2002) and in corticothalamic connections influencing the thalamic reticular nucleus (Zikopoulos and Barbas, 2006;Barrett and Simmons, 2015). This gain mechanism is attracted to causal regularity in the world, giving a probabilistic advantage to generative models that maximize the signal-to-noise ratio (Hohwy, 2012).…”

Section: Varieties Of Attentionmentioning

confidence: 99%

Symptoms and the body: Taking the inferential leap

Bergh

Witthöft

Petersen

et al. 2017

Neuroscience & Biobehavioral Reviews

357

354

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a b s t r a c tThe relationship between the conscious experience of physical symptoms and indicators of objective physiological dysfunction is highly variable and depends on characteristics of the person, the context and their interaction. This relationship often breaks down entirely in the case of "medically unexplained" or functional somatic symptoms, violating the basic assumption in medicine that physical symptoms have physiological causes. In this paper, we describe the prevailing theoretical approach to this problem and review the evidence pertaining to it. We then use the framework of predictive coding to propose a new and more comprehensive model of the body-symptom relationship that integrates existing concepts within a unifying framework that addresses many of the shortcomings of current theory. We describe the conditions under which a close correspondence between the experience of symptoms and objective physiology might be expected, and when they are likely to diverge. We conclude by exploring some theoretical and clinical implications of this new account.

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“…In experiments with BDA injections, one series of sections was processed to visualize boutons and labeled neurons as described previously (Barbas et al, 2005b;Zikopoulos and Barbas, 2006). BDA labeled neurons and terminals were also labeled for immunofluorescence using avidin conjugated probes for visualizing the transported dextran (AlexaFluoro-AvidinD; Molecular Probes).…”

Section: Perfusion and Tissue Processingmentioning

confidence: 99%

Sequence of information processing for emotions based on the anatomic dialogue between prefrontal cortex and amygdala

2007

Self Cite

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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.The amygdala and the prefrontal cortex have synergistic roles in regulating purposive behavior [(Schoenbaum et al., 2000;Izquierdo and Murray, 2005); reviewed in (Barbas, 2000;Bechara et al., 2000)]. The amygdala appears to extract the affective significance of stimuli, and the prefrontal cortex guides goal-directed behavior (Damasio, 1994;Petrides, 1996;Roberts and Wallis, 2000;Levy and Goldman-Rakic, 2000;Fuster, 2000;Barbas et al., 2002). Communication between the amygdala and the prefrontal cortex is bidirectional [e.g., (Nauta, 1961;Pandya et al., 1973;Jacobson and Trojanowski, 1975;Aggleton et al., 1980;Porrino et al., e Current address: Department of Molecular Biomedical Sciences, School of Veterinary Medicine, North Carolina State University, Raleigh, NC. * Corresponding author. Dept. Health Sciences, Boston University, 635 Commonwealth Ave. Room 431, Boston, MA 02215. E-mail address: barbas@bu.edu Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is p...

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Prefrontal Projections to the Thalamic Reticular Nucleus form a Unique Circuit for Attentional Mechanisms

Cited by 297 publications

References 96 publications

Gamma oscillations mediate stimulus competition and attentional selection in a cortical network model

Gamma oscillations mediate stimulus competition and attentional selection in a cortical network model

Symptoms and the body: Taking the inferential leap

Sequence of information processing for emotions based on the anatomic dialogue between prefrontal cortex and amygdala

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