Amyloid pathology and axonal injury after brain trauma.

Objective: To image β-amyloid (Aβ) plaque burden in long-term survivors of traumatic brain injury (TBI), test whether traumatic axonal injury and Aβ are correlated, and compare the spatial distribution of Aβ to Alzheimer disease (AD).

Methods: Patients 11 months to 17 years after moderate-severe TBI underwent (11)C-Pittsburgh compound B ((11)C-PiB)-PET, structural and diffusion MRI, and neuropsychological examination. Healthy aged controls and patients with AD underwent PET and structural MRI.

The role of the right inferior frontal gyrus in the pathogenesis of post-stroke psychosis.

Psychotic symptoms have previously been reported following right hemisphere brain injury. We sought to identify the specific neuroanatomical basis of delusions following stroke by studying a series of patients with post-stroke psychosis. Lesion overlap analysis was conducted on three individuals with delusions following right hemisphere stroke.

FAST INdiCATE Trial protocol. Clinical efficacy of functional strength training for upper limb motor recovery early after stroke: neural correlates and prognostic indicators.

Rationale: Functional strength training in addition to conventional physical therapy could enhance upper limb recovery early after stroke more than movement performance therapy plus conventional physical therapy.

Aims: To determine (a) the relative clinical efficacy of conventional physical therapy combined with functional strength training and conventional physical therapy combined with movement performance therapy for upper limb recovery; (b) the neural correlates of response to conventional physical therapy combined with functional strength training and conventional physical therapy combined with movement performance therapy; (c) whether any one or combination of baseline measures predict motor improvement in response to conventional physical therapy combined with functional strength training or conventional physical therapy combined with movement performance therapy.

Design: Randomized, controlled, observer-blind trial.

Salience network integrity predicts default mode network function after traumatic brain injury.

Efficient behavior involves the coordinated activity of large-scale brain networks, but the way in which these networks interact is uncertain. One theory is that the salience network (SN)--which includes the anterior cingulate cortex, presupplementary motor area, and anterior insulae--regulates dynamic changes in other networks. If this is the case, then damage to the structural connectivity of the SN should disrupt the regulation of associated networks.

Default mode network connectivity predicts sustained attention deficits after traumatic brain injury.

Traumatic brain injury (TBI) frequently produces impairments of attention in humans. These can result in a failure to maintain consistent goal-directed behavior. A predominantly right-lateralized frontoparietal network is often engaged during attentionally demanding tasks.

Inflammation after trauma: microglial activation and traumatic brain injury.

Objective: Patient outcome after traumatic brain injury (TBI) is highly variable. The underlying pathophysiology of this is poorly understood, but inflammation is potentially an important factor. Microglia orchestrate many aspects of this response.

Human θ burst stimulation enhances subsequent motor learning and increases performance variability.

Intermittent theta burst stimulation (iTBS) transiently increases motor cortex excitability in healthy humans by a process thought to involve synaptic long-term potentiation (LTP), and this is enhanced by nicotine. Acquisition of a ballistic motor task is likewise accompanied by increased excitability and presumed intracortical LTP. Here, we test how iTBS and nicotine influences subsequent motor learning.

Effectiveness of a community-based low intensity exercise programme for ambulatory stroke survivors.

Purpose: To establish the feasibility and effectiveness of a community-based exercise programme for ambulatory patients with stroke discharged from rehabilitation.

Method: Eighteen participants were recruited 3-12 months after onset of first stroke. Using a time series experimental design, the group completed a baseline period of 4 weeks (A1), a group exercise programme of low-intensity progressive resistive exercise and functional tasks for lower limb muscles (B) and repeat assessment after cessation of exercise (A2).

The facilitatory effects of intermittent theta burst stimulation on corticospinal excitability are enhanced by nicotine.

Objective: Intermittent theta burst stimulation (iTBS) is increasingly widely used as a means of facilitating corticospinal excitability in the human primary motor cortex. This form of facilitatory plasticity within the stimulated cortex may occur by induction of long term potentiation (LTP). In animal models, agonists of nicotinic acetylcholine receptors have been shown to modulate or induce LTP; we thus sought to test whether nicotine may modulate the effects of iTBS on corticospinal excitability in humans.

Recurrent stroke: where do we stand with the secondary prevention of noncardioembolic ischaemic strokes?

Strokes recur in 6-20% of the patients, most commonly within the first year; after a TIA or minor stroke; most recurrences will occur within the first 90 days. Our ability to identify patients at high risk is poor and most recurrent strokes cannot be explained by traditional risk factors. In 30-45% of the cases the second stroke will be of a different subtype.

Stages of motor output reorganization after hemispheric stroke suggested by longitudinal studies of cortical physiology.

Reorganization of motor circuits in the cerebral cortex is thought to contribute to recovery following stroke. These can be examined with transcranial magnetic stimulation (TMS) using measures of corticospinal tract integrity and intracortical excitability. However, little is known about how these changes develop during the important early period post-stroke and their influence on recovery.

The relationship between brain activity and peak grip force is modulated by corticospinal system integrity after subcortical stroke.

In healthy human subjects, the relative contribution of cortical regions to motor performance varies with the task parameters. Additionally, after stroke, recruitment of cortical areas during a simple motor task varies with corticospinal system integrity. We investigated whether the pattern of motor system recruitment in a task involving increasingly forceful hand grips is influenced by the degree of corticospinal system damage.

A method for quantifying directional strength and motor control of the trunk.

We describe a new apparatus for studying trunk motor control. Quasi-isometric trunk forces are exerted in any horizontal direction while seated, with or without the pelvis stabilised. Trunk force magnitude and direction are measured using a novel transducing system.

Motor system activation after subcortical stroke depends on corticospinal system integrity.

Movement-related brain activation patterns after subcortical stroke are characterized by relative overactivations in cortical motor areas compared with controls. In patients able to perform a motor task, overactivations are greater in those with more motor impairment. We hypothesized that recruitment of motor regions would shift from primary to secondary motor networks in response to impaired functional integrity of the corticospinal system (CSS).

Observations on the human rejection behaviour syndrome: Denny-Brown revisited.

The parietal avoiding-rejection behaviour syndrome, first described by Denny-Brown in the rhesus monkey, has been reported only rarely in humans. Here, we describe a patient with rejection behaviour in the setting of progressive cognitive decline accompanied by cortical myoclonus.