Yoshihito Furusawa

Design of a head fixation device for experiments in behaving monkeys.

We have designed a new device for head fixation of behaving monkeys. The fixation device consists of a duralumin head ring mounted with four screw holders. It is firmly fixed to the animals skull with four stainless steel screw pins. The head ring is then attached to a primate chair in any desirable position and angle using a set of adjustable plates. The device has been used for behavioral training that requires accurate gaze monitoring and for recording single-unit activity over a several-month period. The advantage of our device is that it is simple to use; it can be attached readily without major surgical procedures and it can be quickly removed when experiments are not running. This head fixation system is suitable for behavioral experiments and single-unit recording studies. It may also be applicable for studies on functional imaging of the macaque brain, by constructing it of non-magnetic materials.

The contribution of quasi-joint stiffness of the ankle joint to gait in patients with hemiparesis

BACKGROUND The role of ankle joint stiffness during gait in patients with hemiparesis has not been clarified. The purpose of this study was to determine the contribution of quasi-joint stiffness of the ankle joint to spatiotemporal and kinetic parameters regarding gait in patients with hemiparesis due to brain tumor or stroke and healthy individuals. METHODS Spatiotemporal and kinetic parameters regarding gait in twelve patients with hemiparesis due to brain tumor or stroke and nine healthy individuals were measured with a 3-dimensional motion analysis system. Quasi-joint stiffness was calculated from the slope of the linear regression of the moment-angle curve of the ankle joint during the second rocker. FINDINGS There was no significant difference in quasi-joint stiffness among both sides of patients and the right side of controls. Quasi-joint stiffness on the paretic side of patients with hemiparesis positively correlated with maximal ankle power (r=0.73, P<0.01) and gait speed (r=0.66, P<0.05). In contrast, quasi-joint stiffness in controls negatively correlated with maximal ankle power (r=-0.73, P<0.05) and gait speed (r=-0.76, P<0.05). INTERPRETATION Our findings suggested that ankle power during gait might be generated by increasing quasi-joint stiffness in patients with hemiparesis. In contrast, healthy individuals might decrease quasi-joint stiffness to avoid deceleration of forward tilt of the tibia. Our findings might be useful for selecting treatment for increased ankle stiffness due to contracture and spasticity in patients with hemiparesis.

Orderly activations of human cortical areas during path-planning task.

The functional anatomy of planning was investigated using a path-planning task, which required subjects to find a path to a goal that avoided obstacles and then move a cursor along the path to the goal by manipulating four switches. We analyzed event-related activation in response to four consecutive events during the path-planning task using fMRI. We classified activated cortical regions into four groups based on when each cortical region showed the most significant activation in response to behavioral events during the path-planning task. Our data suggested that each prefrontal and motor cortical area was involved in a different phase of path planning.

Supramarginal activity in interoceptive attention tasks

Interoceptive (feelings from inside organs) attention/awareness (IAA) is a body-related aspect of cognition that pursues homeostasis by detecting afferent signals, and there are practices aimed at focusing ones attention and awareness towards such feelings inside ones own body. There is a claim that these practices improve health which is one reason that neural correlates of such practices and IAA in general have been investigated in previous imaging studies. In several of these studies which used subjects with no or limited experience in IAA practices there was a report of supramarginal (SM) activity during IAA tasks, but the role of SM in IAA remain unclear. We first investigated if we could find similar results in novices, and if this activity is sensitive to the designated body part in the IAA task. We further investigated if these regions would be similarly recruited in subjects with extensive experience of IAA tasks while comparing results with a group of age and gender matched novices. Results in the novices replicated that of previous studies, and we showed this is the same for IAA tasks regarding two different parts of the body. Group comparison results showed opposite profiles of SM activation for the two groups; novices showed activation and the experts showed deactivation of the SM. The results suggest that novices recruit SM during IAA possibly due to lack of experience in those tasks but this could be alleviated for performing IAA as illustrated by activation profile in experts.

Spinal fMRI of Interoceptive Attention/Awareness in Experts and Novices

Many disciplines/traditions that promote interoceptive (inner sensation of body parts) attention/awareness (IAA) train practitioners to both attend to and be aware of interoceptive sensory experiences in body parts. The effect of such practices has been investigated in previous imaging studies but limited to cerebral neural activity. Here, for the first time, we studied the impact of these practices on the spinal neural activity of experts and novices. We also attempted to clarify the effect of constant and deep breathing, a paradigm utilized in concentration practices to avoid mind wandering, on IAA-related spinal neural activity. Subjects performed IAA tasks with and without a deep and constant breathing pattern in two sessions. Results showed that neural activity in the spinal segment innervating the attended-to body area increased in experts (P = 0.04) when they performed IAA and that this increase was significantly larger for experts versus novices in each of the sessions (P = 0.024). The significant effects of IAA and expertise on spinal neural activity are consistent with and elaborate on previous reports showing similar effects on cerebral neural activity. As the spinal cord directly innervates body parts, the results might indicate that IAA has an instantaneous (possibly beneficial) effect on the physical body after extended training.

Cannula-aided penetration: A simple method to insert structurally weak electrodes into brain through the dura mater

We developed a simple and inexpensive method to insert structurally weak electrodes into the brain through the thickened dura mater in chronic animal experiments. It uses a commonly available intravenous (IV) needle and a cannula to secure a small puncture in the dura mater, through which an electrode is advanced into the underlying cerebral cortex. In addition to its simplicity and cost-effectiveness, this method provides greater degree of freedom regarding the shape and the placement of electrodes compared to the conventional guide tube systems.

Development of involuntary movements after ventriculoperitoneal shunting for normal pressure hydrocephalus in a patient with chronic-phase thalamic haemorrhage

Background: Delayed-onset involuntary movements have been described after thalamic stroke. Methods: We treated a patient with involuntary movements that increased after ventriculoperitoneal shunting (VPS) for normal pressure hydrocephalus (NPH) following thalamic haemorrage. One and one-half years after right thalamic and intraventricular haemorrhage, NPH suggested clinical evaluation and neuroimaging studies in a 56-year-old man. Results: Hemidystonia and pseudochoreoathetosis were evident in the left arm, leg and trunk. Proprioceptive impairment and mild cerebellar dysfunction affected the left upper and lower extremity. Yet the patient could walk unassisted and carry out activities of daily living (ADL) rated as 90 points according to the Barthel Index (BI). Lumbar puncture lessened both gait disturbance and cognitive impairment. After VPS, cognition and urinary continence improved, but involuntary movements worsened, precluding unaided ambulation and decreasing the BI score to 65 points. Computed tomography after VPS showed resolution of NPH, while single-photon emission computed tomography showed increased cerebral blood flow after VPS. Conclusion: Increased cerebral blood flow after VPS is suspected to have promoted development of abnormal neuronal circuitry.

P31.16 The utility of diffusion tensor brain fiber tracking to evaluate diffuse axonal injury: Imaging potentially correlates with cognitive disorder

P31.16 The utility of diffusion tensor brain fiber tracking to evaluate diffuse axonal injury: Imaging potentially correlates with cognitive disorder K. Sugiyama , T. Kondo , M. Endo , H. Watanabe , K. Shindo , K. Nishijima , Y. Furusawa , T. Mori , S.I. Izumi 1 1 Tohoku University Graduate School of Medicine, Physical Medicine and Rehabilitation, Japan 2 Tohoku Kouseinenkin General Hospital, Neurology, Japan 3 Tohoku Kouseinenkin General Hospital, Physical Medicine and Rehabilitation, Japan