Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Variations in neural circuitry, inherited or acquired, may underlie important individual differences in thought, feeling, and action patterns. Here, we used task-free connectivity analyses to isolate and characterize two distinct networks typically coactivated during functional MRI tasks. We identified a "salience network," anchored by dorsal anterior cingulate (dACC) and orbital frontoinsular cortices with robust connectivity to subcortical and limbic structures, and an "executive-control network" that links dorsolateral frontal and parietal neocortices. These intrinsic connectivity networks showed dissociable correlations with functions measured outside the scanner. Prescan anxiety ratings correlated with intrinsic functional connectivity of the dACC node of the salience network, but with no region in the executive-control network, whereas executive task performance correlated with lateral parietal nodes of the executive-control network, but with no region in the salience network. Our findings suggest that task-free analysis of intrinsic connectivity networks may help elucidate the neural architectures that support fundamental aspects of human behavior.

https://www.jneurosci.org/content/jneuro/27/9/2349.full.pdf

Dissociable Intrinsic Connectivity Networks for Salience Processing and Executive Control

In response to a peripheral infection, innate immune cells produce pro-inflammatory cytokines that act on the brain to cause sickness behaviour. When activation of the peripheral immune system continues unabated, such as during systemic infections, cancer or autoimmune diseases, the ensuing immune signalling to the brain can lead to an exacerbation of sickness and the development of symptoms of depression in vulnerable individuals. These phenomena might account for the increased prevalence of clinical depression in physically ill people. Inflammation is therefore an important biological event that might increase the risk of major depressive episodes, much like the more traditional psychosocial factors.

/pdf/from-inflammation-to-sickness-and-depression-when-the-immune-maw2hn72o8.pdf

From inflammation to sickness and depression: when the immune system subjugates the brain

The anterior insular cortex (AIC) is implicated in a wide range of conditions and behaviours, from bowel distension and orgasm, to cigarette craving and maternal love, to decision making and sudden insight. Its function in the re-representation of interoception offers one possible basis for its involvement in all subjective feelings. New findings suggest a fundamental role for the AIC (and the von Economo neurons it contains) in awareness, and thus it needs to be considered as a potential neural correlate of consciousness.

How do you feel--now? The anterior insula and human awareness.

As humans, we perceive feelings from our bodies that relate our state of well-being, our energy and stress levels, our mood and disposition. How do we have these feelings? What neural processes do they represent? Recent functional anatomical work has detailed an afferent neural system in primates and in humans that represents all aspects of the physiological condition of the physical body. This system constitutes a representation of 'the material me', and might provide a foundation for subjective feelings, emotion and self-awareness.

How do you feel? Interoception: the sense of the physiological condition of the body.

GABA-like immunoreactivity in the thalamic nucleus submedius of the cat

Functional brain imaging places C-tactile (CT) fibres within an interoceptive network that is important for the sensation of pleasurable touch and emotional well-being, but the circuits that relay this information from periphery to forebrain are not well understood. In vivo single unit recordings from projection neurons in lamina I of the rat spinal cord showed that the activity of CT fibres is integrated with that of nociceptors before being relayed to the brainstem parabrachial nucleus. There is at least one interneuron in the pathway that relays CT activity from mechanoreceptor to lamina I output neuron, with preliminary data suggesting that such interneurons express the γ isoform of protein kinase C and receive inputs from vesicular glutamate transporter three-labelled primary afferents. A role for CT fibres in mechanical allodynia is also suggested, as pilot data shows that these fibres can provide low-threshold inputs to sensitized nociceptive-specific lamina I projection neurons. Thus, the homeostatic signal provided via CT fibres can be directly modulated by pain, placing the CT system firmly within an interoceptive network that regulates the body’s internal environment.

Processing of C-Tactile Information in the Spinal Cord

Modular architectonic parcellation of the insula in the macaque monkey

A neurobiological view of pain as a homeostatic emotion

Mental energy – an fMRI investigation of the anterior insular and the anterior cingulate network

A.D. (Bud) Craig

Papers

GABA-like immunoreactivity in the thalamic nucleus submedius of the cat

Processing of C-Tactile Information in the Spinal Cord

Modular architectonic parcellation of the insula in the macaque monkey

A neurobiological view of pain as a homeostatic emotion

Mental energy – an fMRI investigation of the anterior insular and the anterior cingulate network