raphe nuclei

Examples of raphe nuclei in the following topics:

• Reticular Formation

  • The raphe nuclei form a ridge in the middle of the reticular formation, and directly to its periphery, there is a division called the medial reticular formation.
  • The lateral reticular formation is close to the motor nuclei of the cranial nerves and mostly mediates their function.
  • The raphe nuclei is the place of synthesis of the neurotransmitter serotonin, which plays an important role in mood regulation.
  • The nuclei can be differentiated by function, cell type, and projections of efferent or afferent nerves.
  • Reticular formation nuclei that modulate activity of the cerebral cortex are part of the reticular activating system.

• Stress and Disease

  • Serotonin transmission from both the caudal raphe nuclei and rostral raphe nuclei is reduced in patients with depression compared with non-depressed controls.

• Penis

  • The perineal raphe is the noticeable line along the underside of the penis.
  • The raphe is the noticeable ridge between the halves of the penis.

• Pons

  • The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that regulate sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.
  • The alar plate produces sensory neuroblasts, which will give rise to the solitary nucleus and its special visceral afferent column, the cochlear and vestibular nuclei (which form the special somatic afferent fibers of the vestibulocochlear nerve), the spinal and principal trigeminal nerve nuclei (which form the general somatic afferent column of the trigeminal nerve), and the pontine nuclei, which is involved in motor activity.
  • Basal plate neuroblasts give rise to the abducens nucleus (forms the general somatic efferent fibers), the facial and motor trigeminal nuclei (form the special visceral efferent column), and the superior salivatory nucleus, which forms the general visceral efferent fibers of the facial nerve.
  • A number of cranial nerve nuclei are present in the pons:

• Epithalamus and Pineal Gland

  • The habenular commissure is a band of nerve fibers situated in front of the pineal gland that connects the habenular nuclei on both sides of the diencephalon.
  • The stria medullaris, also known as stria medullaris thalami, is a fiber bundle containing afferent fibers from the septal nuclei, lateral preoptic hypothalamic region, and anterior thalamic nuclei to the habenula.

• Basal Ganglia

  • The basal ganglia (or basal nuclei, ) are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit.
  • The basal nuclei are often referred to as the basal ganglia.
  • The main components of the basal nuclei are labeled in purple.

• Parts of the Cerebellum

  • This complex neural network gives rise to a massive signal-processing capability, but almost all of its output is directed to a set of small deep cerebellar nuclei lying in the interior of the cerebellum.
  • Its primary connections are with the vestibular nuclei, although it also receives visual and other sensory input.
  • It sends fibers to deep cerebellar nuclei that in turn project to both the cerebral cortex and the brain stem, thus providing modulation of descending motor systems.
  • It receives input exclusively from the cerebral cortex (especially the parietal lobe) via the pontine nuclei (forming corticopontocerebellar pathways), and sends output mainly to the ventrolateral thalamus (in turn connected to motor areas of the premotor cortex and primary motor area of the cerebral cortex) and to the red nucleus.

• Midbrain

  • Anatomically, it comprises the tectum (or corpora quadrigemina), tegmentum, ventricular mesocoelia (or "iter"), and the cerebral peduncles, as well as several nuclei and fasciculi.
  • The tegmentum is involved in many unconscious homeostatic and reflexive pathways, and is the motor center that relays inhibitory signals to the thalamus and basal nuclei to prevent unwanted body movement.
  • The nuclei of cranial nerves III and IV are located in the tegmentum portion of the midbrain.
  • The cerebral peduncles are located on either side of the midbrain and are its most anterior part, acting as the connectors between the rest of the midbrain and the thalamic nuclei.

• Limbic System

  • It includes the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex, and fornix, and supports a variety of functions including emotion, behavior, motivation, long-term memory, and olfaction.
  • Fornix: A white matter structure that carries signals from the hippocampus to the mammillary bodies and septal nuclei.
  • The septal nuclei receive reciprocal connections from the olfactory bulb, hippocampus, amygdala, hypothalamus, midbrain, habenula, cingulate gyrus, and thalamus.

• Thalamus

  • Thalamic nuclei have strong reciprocal connections with the cerebral cortex, forming thalamo-cortico-thalamic circuits that are believed to be involved with consciousness.