Transcranial laser doppler mapping of activation flow coupling of the rat somatosensory cortex

Signal averaged laser Doppler (LD) through a thinned skull over the rat som atosensory cortex was used to map the spatial and temporal characteristics of activation-flow coupling, the change in regional cerebral blood flow (CB F) due to neuronal activation, in response to electrical forepaw stimulatio n. The location of maximal changes in amplitude of the LD response was repr oducibly recorded at 4-5 mm lateral to Bregma. This location is very simila r but slightly posterior and lateral to results obtained from electrophysio logical, magnetic resonance imaging (MRI), and optical imaging studies. The latency of the activation-flow coupling (AFC) response was inversely corre lated to response amplitude, with shorter latencies at positions of maximal amplitude. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.