Biomaterial Database

Anatomical identification of a telencephalic somatosensory area in a reptile, Caiman crocodilus. 1994

M B Pritz, and M E Stritzel

Division of Neurological Surgery, California College of Medicine, University of California, Irvine Medical Center, Orange.

Telencephalic projections of a thalamic somatosensory area were investigated in a reptilian species, Caiman crocodilus, by means of horseradish peroxidase (HRP) neurohistochemistry. Injections of HRP into the medialis complex labeled axons that leave the ventral aspect of this nucleus to enter the dorsal peduncle of the lateral forebrain bundle where they ascend. These fibers course rostrally to enter the central portion of the lateral forebrain bundle. Here, axons turn dorsally, pass through, and probably synapse on, interposed neurons of the ventrolateral area, to end in a central portion of the dorsal ventricular ridge (DVR). These findings were confirmed by HRP injections into this somatosensory area of the DVR that retrogradely labeled neurons in the medialis complex. This telencephalic somatosensory area identified in transverse sections was then reconstructed onto a surface view of the DVR. The locus of this forebrain somesthetic region was then compared with the location of the DVR projection areas of auditory (nucleus reuniens) and visual (nucleus rotundus) thalamic nuclei. This analysis suggested two features. First, telencephalic terminal zones of dorsal thalamic nuclei were largely separate and non-overlapping. Second, the locus of termination in the DVR of each thalamic nucleus reflected each nucleus's topography in the dorsal thalamus. Additional parallels in the neural circuitry of auditory, visual, and somatosensory systems that synapse in the midbrain and project to the DVR are documented.

UI	MeSH Term	Description	Entries
D009415	Nerve Net	A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.	Neural Networks (Anatomic),Nerve Nets,Net, Nerve,Nets, Nerve,Network, Neural (Anatomic),Networks, Neural (Anatomic),Neural Network (Anatomic)
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D002552	Cerebral Ventricles	Four CSF-filled (see CEREBROSPINAL FLUID) cavities within the cerebral hemispheres (LATERAL VENTRICLES), in the midline (THIRD VENTRICLE) and within the PONS and MEDULLA OBLONGATA (FOURTH VENTRICLE).	Foramen of Monro,Cerebral Ventricular System,Cerebral Ventricle,Cerebral Ventricular Systems,Monro Foramen,System, Cerebral Ventricular,Systems, Cerebral Ventricular,Ventricle, Cerebral,Ventricles, Cerebral,Ventricular System, Cerebral,Ventricular Systems, Cerebral
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
D000489	Alligators and Crocodiles	Large, long-tailed reptiles, including caimans, of the order Loricata.	Caimans,Crocodiles,Alligators,Caymans,Alligator,Caiman,Cayman,Crocodile,Crocodiles and Alligators
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001369	Axons	Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.	Axon
D012677	Sensation	The process in which specialized SENSORY RECEPTOR CELLS transduce peripheral stimuli (physical or chemical) into NERVE IMPULSES which are then transmitted to the various sensory centers in the CENTRAL NERVOUS SYSTEM.	Sensory Function,Organoleptic,Function, Sensory,Functions, Sensory,Sensations,Sensory Functions