The striatum in the hedgehog tenrec: histochemical organization and cortical afferents

Brain Res. 2005 Feb 9;1034(1-2):90-113. doi: 10.1016/j.brainres.2004.11.047.

Abstract

In order to get insight into the striopallidal organization in mammals with little differentiated brain the striatum of the lesser hedgehog tenrec (Afrotheria) was characterized histochemically and analysed with regard to its cortical afferents using axonal tracer substances. The majority of neocortical cells projecting to the striatum were found bilaterally in the layers 2 and 3 of the frontal hemisphere; caudalwards the relative number of cells increased somewhat in the upper layer 5. There was a topographical organization as far as the allocortical projections appeared confined to the ventral striatum, and the efferents from hippocampal, posterior paleocortical, somatosensory and audiovisual areas were distributed in largely different striatal territories. Projections from the anterior frontal cortex, on the other hand, terminated extensively upon the caudate-putamen and also involved the nucleus accumbens and the olfactory tubercle. In the latter region the molecular layer was especially involved. The entorhinal cortex also projected heavily to the olfactory tubercle but unlike other species it scarcely involved the nucleus accumbens. The cortical fibers were distributed in a relatively homogenous fashion within their striatal territory and there was little evidence for patches of high density terminations. Islands of low density labeling, however, were noted occasionally in the caudate-putamen. These islands were partly similar in size as the patches of neuropil staining obtained with anti-calretinin and anti-substance P. There were also hints for the presence of a shell-like region in the nucleus accumbens stained with anti-dopamine transporter and NADPh-diaphorase. The classical striosome-matrix markers such as calbindin, acetylcholinesterase and enkephalin, however, failed to reveal any compartmental organization.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholinesterase / biosynthesis
  • Animals
  • Biomarkers / analysis
  • Biotin / analogs & derivatives*
  • Brain Mapping
  • Cerebral Cortex / anatomy & histology*
  • Cerebral Cortex / cytology
  • Cerebral Cortex / metabolism
  • Corpus Striatum / anatomy & histology*
  • Corpus Striatum / cytology
  • Corpus Striatum / metabolism
  • Dextrans
  • Dopamine Plasma Membrane Transport Proteins
  • Histocytochemistry
  • Insectivora / anatomy & histology*
  • Membrane Glycoproteins / biosynthesis
  • Membrane Transport Proteins / biosynthesis
  • NADPH Dehydrogenase / biosynthesis
  • Neostriatum / cytology
  • Neostriatum / metabolism
  • Nerve Tissue Proteins / biosynthesis
  • Neural Pathways / anatomy & histology*
  • Neural Pathways / cytology
  • Neural Pathways / metabolism
  • Nucleus Accumbens / cytology
  • Nucleus Accumbens / metabolism
  • Olfactory Pathways / cytology
  • Olfactory Pathways / metabolism
  • Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate

Substances

  • Biomarkers
  • Dextrans
  • Dopamine Plasma Membrane Transport Proteins
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
  • biotinylated dextran amine
  • Biotin
  • NADPH Dehydrogenase
  • Acetylcholinesterase