HINTS IN THE ER- case report

Vertigo is a false sense of motion of either the environment or self and is diagnosed in approximately half of the patients with dizziness. Acute spontaneous onset of vertigo is called acute vestibular neuritis (AVN). It is caused by peripheral lesion and requires symptomatic treatment. The symptoms of AVN can mimic a central pathology like cerebellar or brainstem infarction with no concomitant red-flag manifestation. Magnetic Resonance Neuroimaging with Diffusion-weighted imaging (MRI-DWI) as well as Computed Tomography (CT) scan delivers false negatives results what significantly delays stroke treatment. HINTS is an acronym for the battery of three bedside tests of ocular motor physiology. The method is more sensitive in diagnosing posterior circulation infarct than MRI-DWI with specificity -96 %. We present a case of a patient with vertigo who underwent two cranial CT scans and neurological examination. HINTS was worrisome. The brainstem infarct diagnosis was confirmed by MRI-DWI.

Promoting plasticity in the somatosensory cortex to alter motor physiology

Somatosensory pathways and cortices contribute to the control of human movement. In humans, non-invasive transcranial magnetic stimulation techniques to promote plasticity within somatosensory pathways and cortices have revealed potent effects on the neurophysiology within motor cortices. In this mini-review, we present evidence to indicate that somatosensory cortex is positioned to influence motor cortical circuits and as such, is an ideal target for plasticity approaches that aim to alter motor physiology and behavior in clinical populations.

THE DISAPPEARING LESION: SIGMUND FREUD, SENSORY-MOTOR PHYSIOLOGY, AND THE BEGINNINGS OF PSYCHOANALYSIS

Freud's criticism of the localization project as carried out by Theodor Meynert and Carl Wernicke has usually been seen as marking his break with contemporaneous brain science. In this article, however, I show that Freud criticized localization not by turning his back on brain science, but rather by radicalizing some of its principles. In particular, he argued that the physiological pretensions of the localization project remained at odds with its uncritical importation of psychological categories. Further, by avoiding a confusion of categories and adopting a parallelist reading, Freud was able to develop a fully “physiologized” account of nervous processes. This opened up the possibility for forms of mental pathology that were not reliant on the anatomical lesion. Instead, Freud suggested that lived experience might be able to create a pathological organization within the nervous system. This critique—a passage through, rather than a turn away from, brain science—opened the possibility for Freud's theory of the unconscious and his developing psychoanalysis. On a methodological level, this article aims to show how the intellectual history of modern Europe can gain from taking seriously the impact of the brain sciences, and by applying to scientific texts the methods and reading practices traditionally reserved for philosophical or literary works.

Rapid feedback corrections during a bimanual postural task

An important observation in motor physiology is that even the fastest feedback responses can be modified in a task-dependent manner. However, whether or not such responses in one limb can be modulated based on online sensory feedback from other limbs is still unknown. We tested this using a bimanual postural control task, in which the two hands either controlled two separate cursors (double-cursor task) or a single cursor displayed at the spatial average between the hands (single-cursor task). In the first experiment, the two hands were symmetrically perturbed outwards. In the double-cursor task, the participants therefore had to return their hands to the targets, whereas in the single-cursor task no correction was necessary. Within 50 ms, the electromyographic activity showed significantly smaller responses in the single- compared with the double-cursor task. In the second experiment, the perturbation direction of the left hand (inward/outward) was randomized, such that participants could not preplan their response before perturbation onset. Results show that the behavior of the right arm in the one-cursor task depended on online feedback coming from the left arm: the muscular response was modulated within 75 ms based on directionally specific information of the left arm. These results suggest that sensory feedback from one limb can quickly modify the perturbation response of another limb in a task-dependent manner.