Neuregulin-1/ErbB4 Signaling Regulates Visual Cortical Plasticity.

Experience alters cortical networks through neural plasticity mechanisms. During a developmental critical period, the most dramatic consequence of occluding vision through one eye (monocular deprivation) is a rapid loss of excitatory synaptic inputs to parvalbumin-expressing (PV) inhibitory neurons in visual cortex. Subsequent cortical disinhibition by reduced PV cell activity allows for excitatory ocular dominance plasticity.

Inhibitory Neuron Transplantation into Adult Visual Cortex Creates a New Critical Period that Rescues Impaired Vision.

The maturation of inhibitory circuits in juvenile visual cortex triggers a critical period in the development of the visual system. Although several manipulations of inhibition can alter the timing of the critical period, none have demonstrated the creation of a new critical period in adulthood. We developed a transplantation method to reactivate critical period plasticity in the adult visual cortex.

Sensory Stimulation-Based Complete Protection from Ischemic Stroke Remains Stable at 4 Months Post-Occlusion of MCA.

Previous research from our lab has shown that when using a rodent model of ischemic stroke (permanent middle cerebral artery occlusion), mild sensory stimulation, when delivered within two hours of ischemic onset, completely protects the cortex from impending ischemic stroke damage when assessed 24 hours post-occlusion. However, the long-term stability of this protection remains unclear. Using intrinsic signal optical imaging for assessment of cortical function, laser speckle imaging for assessment of blood flow, a battery of behavioral tests and cresyl violet for histological assessment, the present study examined whether this protection was long-lasting.

Permanent cerebral vessel occlusion via double ligature and transection.

Stroke is a leading cause of death, disability, and socioeconomic loss worldwide. The majority of all strokes result from an interruption in blood flow (ischemia). Middle cerebral artery (MCA) delivers a great majority of blood to the lateral surface of the cortex, is the most common site of human stroke, and ischemia within its territory can result in extensive dysfunction or death.

Mild sensory stimulation protects the aged rodent from cortical ischemic stroke after permanent middle cerebral artery occlusion.

Background: Accumulated research has shown that the older adult brain is significantly more vulnerable to stroke than the young adult brain. Although recent evidence in young adult rats demonstrates that single-whisker stimulation can result in complete protection from ischemic damage after permanent middle cerebral artery occlusion (pMCAO), it remains unclear whether the same treatment would be effective in older animals.

Methods And Results: Aged rats (21 to 24 months of age) underwent pMCAO and subsequently were divided into "treated" and "untreated" groups.

A rat's whiskers point the way toward a novel stimulus-dependent, protective stroke therapy.

Stroke is the fourth leading cause of death in the United States and the leading cause of long-term disability. Ischemic stroke, due to an interruption in blood supply, is particularly prevalent; 87% of all strokes are ischemic. Unfortunately, current options for acute treatment are extremely limited and there is a great need for new treatment strategies.

Mild sensory stimulation reestablishes cortical function during the acute phase of ischemia.

When delivered within 1 and in most cases 2 h of permanent middle cerebral artery occlusion (pMCAO), mild sensory stimulation (intermittent single whisker stimulation) was shown to be completely neuroprotective 24 h after pMCAO in a rodent model of ischemic stroke, according to assessment with multiple techniques (Lay et al., 2010). The acute effect of stimulation treatment on the ischemic cortex, however, has yet to be reported.

Amount but not pattern of protective sensory stimulation alters recovery after permanent middle cerebral artery occlusion.

Background And Purpose: Using a rodent model of ischemia (permanent middle cerebral artery occlusion), our laboratory previously demonstrated that 4.27 minutes of patterned single-whisker stimulation delivered over 120 minutes can fully protect from impending damage when initiated within 2 hours of permanent middle cerebral artery occlusion ("early"). When initiated 3 hours postpermanent middle cerebral artery occlusion ("late"), stimulation resulted in irreversible damage.

Mild sensory stimulation completely protects the adult rodent cortex from ischemic stroke.

Despite progress in reducing ischemic stroke damage, complete protection remains elusive. Here we demonstrate that, after permanent occlusion of a major cortical artery (middle cerebral artery; MCA), single whisker stimulation can induce complete protection of the adult rat cortex, but only if administered within a critical time window. Animals that receive early treatment are histologically and behaviorally equivalent to healthy controls and have normal neuronal function.