Cortical connections to area TE in monkey: hybrid modular and distributed organization

Cereb Cortex. 2010 Feb;20(2):257-70. doi: 10.1093/cercor/bhp096. Epub 2009 May 14.

Abstract

To investigate the fine anatomical organization of cortical inputs to visual association area TE, 2-3 small injections of retrograde tracers were made in macaque monkeys. Injections were made as a terminal procedure, after optical imaging and electrophysiological recording, and targeted to patches physiologically identified as object-selective. Retrogradely labeled neurons occurred in several unimodal visual areas, the superior temporal sulcus, intraparietal sulcus (IPS), and prefrontal cortex (PFC), consistent with previous studies. Despite the small injection size (<0.5 mm wide), the projection foci in visual areas, but not in IPS or PFC, were spatially widespread (4-6 mm in extent), and predominantly consisted of neurons labeled by only one of the injections. This can be seen as a quasi-modular organization. In addition, within each projection focus, there were scattered neurons projecting to one of the other injections, together with some double-labeled (DL) neurons, in a more distributed pattern. Finally, projection foci included smaller "hotspots," consisting of intermixed neurons, single-labeled by the different injections, and DL neurons. DL neurons are likely the result of axons having extended, spatially separated terminal arbors, as demonstrated by anterograde experiments. These results suggest a complex, hybrid connectivity architecture, with both modular and distributed components.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / physiology
  • Axons / ultrastructure
  • Brain Mapping
  • Electrophysiology
  • Fluorescent Antibody Technique
  • Macaca mulatta
  • Male
  • Microscopy, Fluorescence
  • Nerve Net / anatomy & histology
  • Nerve Net / physiology
  • Neuronal Tract-Tracers
  • Neurons / cytology
  • Neurons / physiology
  • Parietal Lobe / physiology
  • Pattern Recognition, Visual / physiology*
  • Photic Stimulation
  • Prefrontal Cortex / physiology
  • Temporal Lobe / anatomy & histology*
  • Temporal Lobe / physiology
  • Visual Cortex / anatomy & histology*
  • Visual Cortex / physiology
  • Visual Pathways / anatomy & histology*
  • Visual Pathways / physiology
  • Voltage-Sensitive Dye Imaging

Substances

  • Neuronal Tract-Tracers