Impaired Neurovascular Coupling by Transhemispheric Diaschisis in Rat Cerebral Cortex

Abstract

In acute brain disorders, elimination of the excitatory output from an injured brain region reduces activity in connecting brain regions remote from the lesion site (i.e., diaschisis). The authors examined the effect of functional ablation of the left cerebral cortex by cortical spreading depression (CSD) or topical application of tetrodotoxin on single cell spiking activity, baseline CBF, and neurovascular coupling in the right rat sensory cortex. CSD or tetrodotoxin in left cortex reduced the right cortical spontaneous spike rate by 36% and 45%, respectively. Baseline CBF in the right cortex was unaffected by a left-sided CSD, but decreased by 12% for left cortical application of tetrodotoxin. This suggested dissociation between spontaneous spiking activity and basal CBF. Left in-fraorbital nerve stimulation evoked local field potentials in right cerebral cortex that were reduced in amplitude by 19% for left CSD and by 23% for left tetrodotoxin application. The corresponding declines in the evoked CBF responses were 42% for CSD and 23% for tetrodotoxin. Vascular reactivity to adenosine remained unchanged in right cortex. Thus, transhemispheric diaschisis produced a pronounced decrease in the spontaneous spike rate accompanied by no reduction or a small reduction in basal CBF, and an attenuation in amplitudes of evoked synaptic responses and corresponding rises in CBF. The findings suggest that disturbed neurovascular coupling may contribute to the disturbance in brain function in acute transhemispheric diaschisis.

Melatonin improves presynaptic protein, SNAP‐25, expression and dendritic spine density and enhances functional and electrophysiological recovery following transient focal cerebral ischemia in rats

“…One interesting finding in the present study was that a possible linkage might exist between persistent transmission failure of the SSEPs and the reductions in cortical dendritic spine density identified both in the ipsilateral ischemic penumbral and the contralateral, homotopic regions after transient MCA occlusion [56–58]. Neuroanatomical and electrophysiological plasticity is well known in lesions of the hippocampus, but remains a subject of some controversy in the neocortex [56].…”

Quantitative Characterization of Functional Anatomical Contributions to Cognitive Control under Uncertainty

“…Recent evidence suggests that resting state glutamate in the ACC is predictive of BOLD changes that result from cognitive control demands (Falkenberg, Westerhausen, Specht, & Hugdahl, 2012). An increase in the BOLD signal directly and monotonically reflects an increase in neural activity (Logothetis, Pauls, Augath, Trinath, & Oeltermann, 2001) while decrease in the BOLD signal (deactivation) is associated with reduction of neuronal activity (Enager, Gold, & Lauritzen, 2004; Fox et al, 2005; Gold & Lauritzen, 2002; Lauritzen, 2005; Logothetis, 2008; Offenhauser, Thomsen, Caesar, & Lauritzen, 2005; Raichle & Mintun, 2006; Shmuel et al, 2002). Coupling between BOLD signal and neuronal firing rate, as well as local field potentials, has been demonstrated (Heeger, Huk, Geisler, & Albrecht, 2000; Logothetis et al, 2001; Mukamel et al, 2005; Rees et al, 2000).…”

Visual Motion Perception Deficits Due to Cerebellar Lesions Are Paralleled by Specific Changes in Cerebro-Cortical Activity

“…Although cerebellar damage or inactivation induces changes in cerebro-cortical metabolism, a phenomenon referred to as (crossed) cerebello-cerebral diaschisis (Broich et al, 1987;Gó mez Beldarrain et al, 1997;Tecco et al, 1998;Gasparini et al, 1999;Gold and Lauritzen, 2002;Vokaer et al, 2002;Enager et al, 2004), a thorough description of cerebral activity after loss of cerebellar input is missing to date. The goal of this study was to provide a detailed description of cerebro-cortical functioning after cerebellar lesions and to correlate cognitive performance with neurophysiological properties of cerebral cortex such as recorded by magnetoencephalography (MEG).…”