Table 1.
CNS nuclei with direct connections with vagal brainstem nuclei involved in the regulation of GI functions1
| Location | Neuroanatomical connections with brainstem vagal nuclei | GI functions | |
|---|---|---|---|
| Hindbrain | |||
| Spinal cord | GI afferents terminate within the thoracic (T1-T3) spinal cord | Spinal afferent inputs terminate within the NTS (spinosolitary tract) | Relay nociceptive information; spinal afferents also respond to low-pressure distention and innocuous chemostimulation |
| Area postrema | Dorsal to the NTS, adjacent to the 4th ventricle | AP neurons innervate the NTS;NTS and DMV neuronal dendrites reach the AP | Chemoreceptor trigger zone;Contain receptors for, and respond to, a variety of circulating factors including immune and inflammatory mediators |
| Midbrain | |||
| Paraventricular nucleus of the hypothalamus (PVN) | Hypothalamus; adjacent to 3rd ventricle within periventricular zone | Reciprocal connections with DVC; release neurotransmitters into neurohypophysis and hormones into hypophysial portal system; | Stress-induced GI responses, including arousal, anxiety and depression |
| Arcuate nucleus (Arc) | Hypothalamus; adjacent to the 3rd ventricle, in close apposition to median eminence | Reciprocal connections with DVC | Integration of endocrine and behavioral aspects of GI functions Modulation of food intake and satiety |
| Barrington’s nucleus | Dorsolateral pons | Receives inputs from NTS | Regulation of bladder and colon function;assimilation of emotional and cognitive behaviors with GI functions |
| Periaqueductal gray (PAG) | Surrounds cerebral aqueduct from dorsal tegmental nucleus to posterior commissure | Dense innervation from NTS | Integration of fear and anxiety; pain modulation |
| Locus coeruleus (LC) | A6 noradrenergic region;located at rostral pons at lateral floor of 4th ventricle | Reciprocal connections with DVC | Maintenance of arousal and attention;integration of emotional responses and cognitive inputs with GI functions; stress |
| Forebrain | |||
| Central nucleus of the amygdala (CeA) | Heterogeneous complex within anteromedial temporal lobe | Reciprocal connections with DVC | Learning and memory; integrative of emotional and aversive inputs with learning, memory and autonomic GI functions; prominent role in anxiety and stress-related GI disorders |
| Bed Nucleus of the Stria Terminalis (BNST) | Part of the extended amygdala | Reciprocal connections with DVC | Processing and consolidation of behavior and emotions; regulation of HPA axis and autonomic (GI) responses to stress |
| Cortex | Direct descending connections (infralimbic and prelimbic cortex) to DVC; indirect descending connections via hypothalamus and amygdala | Integration of affect, emotion and memory with autonomic (GI) functions |