The cholinergic basal forebrain in the ferret and its inputs to the auditory cortex.
Bottom Line: Epipial tracer deposits and injections of the immunotoxin ME20.4-SAP (monoclonal antibody specific for the p75 neurotrophin receptor conjugated to saporin) in the auditory cortex showed that cholinergic inputs originate almost exclusively in the ipsilateral nucleus basalis.Moreover, tracer injections in the nucleus basalis revealed a pattern of labelled fibres and terminal fields that resembled acetylcholinesterase fibre staining in the auditory cortex, with the heaviest labelling in layers II/III and in the infragranular layers.The widespread distribution of cholinergic inputs from the nucleus basalis to both primary and higher level areas of the auditory cortex suggests that acetylcholine is likely to be involved in modulating many aspects of auditory processing.
Affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK.Show MeSH
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Mentions: Figure1 summarizes the different experimental approaches used in this study and the number of animals included for each experimental procedure. Five animals were used to determine the distribution of cholinergic and inhibitory neurons in the BF and of acetylcholinesterase (AChE) fibres in the auditory cortex (Fig.1A). The connections between these brain regions were identified by making epipial neural tracer deposits on the surface of the auditory cortex (Fig.1B, n = 3), by evaluation of cell loss in the NB after multiple injections of the cholinergic immunotoxin ME20.4-SAP were made in the auditory cortex (Fig.1C, n = 1), and by injecting neural tracers into the NB (Fig.1D, n = 5).
Affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK.