Differences in anatomical connections across distinct areas in the rodent prefrontal cortex. (16th February 2017)

• Record Type: Journal Article
• Authors: Bedwell, Stacey A.; Billett, E. Ellen; Crofts, Jonathan J.; Tinsley, Chris J.
• Editors: Bolam, Paul
• Is Part Of: European journal of neuroscience. Volume 45:Number 6(2017)
• Page Start: 859
• Page End: 873
• Publication Date: 2017-02-16
• Subjects: cortical circuitry -- organization -- sensory‐motor cortex -- temporal cortex -- tracing; Nervous system -- Periodicals; 612.8
• DOI: 10.1111/ejn.13521
• Languages: English
• ISSNs: 0953-816X

Abstract

Abstract: Prefrontal cortex (PFC) network structure is implicated in a number of complex higher‐order functions and with a range of neurological disorders. It is therefore vital to our understanding of PFC function to gain an understanding of its underlying anatomical connectivity. Here, we injected Fluoro‐Gold and Fluoro‐Ruby into the same sites throughout rat PFC. Tracer injections were applied to two coronal levels within the PFC (anterior +4.7 mm to bregma and posterior +3.7 mm to bregma). Within each coronal level, tracers were deposited at sites separated by approximately 1 mm and located parallel to the medial and orbital surface of the cortex. We found that both Fluoro‐Gold and Fluoro‐Ruby injections produced prominent labelling in temporal and sensory‐motor cortex. Fluoro‐Gold produced retrograde labelling and Fluoro‐Ruby largely produced anterograde labelling. Analysis of the location of these connections within temporal and sensory‐motor cortex revealed a consistent topology (as the sequence of injections was followed mediolaterally along the orbital surface of each coronal level). At the anterior coronal level, injections produced a similar topology to that seen in central PFC in earlier studies from our laboratory (i.e. comparing equivalently located injections employing the same tracer), this was particularly prominent within temporal cortex. However, at the posterior coronal level this pattern of connections differed significantly, revealing higher levels of reciprocity, in both temporal cortex and sensory‐motor cortex. Our findings indicate changes in the relative organization of connections arising from posterior in comparison to anterior regions of PFC, which may provide a basis to determine how complex processes are organized. Abstract : Anterograde (Fluoro‐Ruby) and retrograde (Fluoro‐Gold) tracer injections were made into anterior and posterior regions of prefrontal cortex. The resultant labelling in temporal and sensory‐motor cortices revealed clear differences in the organization of connections between anterior and posterior PFC. The key finding is that of increased similarity between retrograde and anterograde projection locations within temporal and sensorimotor cortex following injections into posterior PFC.