Inverse relation between motion perception and postural responses induced by motion of a touched object.

Self vs. external attribution of motions based on vestibular cues is suggested to underlie our coherent perception of object motion and self-motion. However, it remains unclear whether such attribution also underlies sensorimotor responses.

Ambulatory intracranial pressure in humans: ICP increases during movement between body positions.

Introduction: Positional changes in intracranial pressure (ICP) have been described in humans when measured over minutes or hours in a static posture, with ICP higher when lying supine than when sitting or standing upright. However, humans are often ambulant with frequent changes in position self-generated by active movement.

Research Question: We explored how ICP changes during movement between body positions.

ICP during head movement: significance of the venous system.

Background: It is thought that the internal jugular veins (IJV) are the primary route for cranial venous outflow in supine position and the vertebral venous plexus when upright. Previous studies have noted a greater increase in intracranial pressure (ICP) when subjects turn their head in one direction compared to the other, but no clear cause had been investigated. We hypothesised that in the supine position, head turning and consequently obstructing the IJV draining the dominant transverse sinus (TVS) would lead to a greater rise in ICP compared to turning to the non-dominant side.

Reflexive and volitional saccadic eye movements and their changes in age and progressive supranuclear palsy.

Background And Objectives: Saccades, rapid movements of the eyes towards a visual or remembered target, are useful in understanding the healthy brain and the pathology of neurological conditions such as progressive supranuclear palsy (PSP). We set out to investigate the parameters of horizontal reflexive and volitional saccades, both visually guided and memory-guided, over a 1 min epoch in healthy individuals and PSP patients.

Methods: An experimental paradigm tested reflexive, volitional visually guided, and volitional memory-guided saccades in young healthy controls (n = 14; 20-31 years), PSP patients (n = 11; 46-75 years) and older age-matched healthy controls (n = 6; 56-71 years).

Ocular myasthenia gravis saccades as a measure of extraocular muscle function.

Background: It is important to understand the pathophysiology of ocular myasthenia gravis (OMG) to improve treatment.

Aim: To use modern video-oculography to characterise saccadic eye movements in patients with OMG, including anti-AChR, anti-MuSK, anti-LRP4, and seronegative OMG.

Methods: In total, 21 patients with OMG and five age-matched healthy control subjects underwent video-oculography.

Persistent Postural-Perceptual Dizziness (PPPD) from Brain Imaging to Behaviour and Perception.

Persistent postural-perceptual dizziness (PPPD) is a common cause of chronic dizziness associated with significant morbidity, and perhaps constitutes the commonest cause of chronic dizziness across outpatient neurology settings. Patients present with altered perception of balance control, resulting in measurable changes in balance function, such as stiffening of postural muscles and increased body sway. Observed risk factors include pre-morbid anxiety and neuroticism and increased visual dependence.

Altered visual and haptic verticality perception in posterior cortical atrophy and Alzheimer's disease.

There is increasing theoretical and empirical support for the brain combining multisensory information to determine the direction of gravity and hence uprightness. A fundamental part of the process is the spatial transformation of sensory signals between reference frames: eye-centred, head-centred, body-centred, etc. The question 'Am I the right way up?' posed by a patient with posterior cortical atrophy (PCA) suggests disturbances in upright perception, subsequently investigated in PCA and typical Alzheimer's disease (tAD) based on what looks or feels upright.

Case Report: Acute Onset Fear of Falling and Treatment With "Cognitive Physical Therapy".

Fear of falling (FoF) is prevalent in older adults, especially those with previous falls, and typically starts insidiously. We present a 78-year-old woman with an abrupt onset FoF and no history of falls, balance problems, vertigo, oscillopsia, psychiatric or psychological issues to account for this. These cognitive changes led to a behavioural alteration of her gait that became slow and wide-based, with her gaze fixed on the floor.

Voluntary steps and gait initiation.

This chapter explores mechanisms that control goal-directed steps for the purpose of reorienting the body or initiating gait. A key issue concerns the control of balance. We argue that standing balance is relinquished while the stepping foot is in the air thus allowing the body to fall under gravity.

The Throw-and-Catch Model of Human Gait: Evidence from Coupling of Pre-Step Postural Activity and Step Location.

Postural activity normally precedes the lift of a foot from the ground when taking a step, but its function is unclear. The throw-and-catch hypothesis of human gait proposes that the pre-step activity is organized to generate momentum for the body to fall ballistically along a specific trajectory during the step. The trajectory is appropriate for the stepping foot to land at its intended location while at the same time being optimally placed to catch the body and regain balance.