Biomedical subjects

Tomoka Naganuma

Publications and source records attributed to Tomoka Naganuma.

4 recordsLinked to original sources

PubMed2005

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 animal's 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.

Action Potentials↗

PubMed2005

Information processing of geometrical features of a surface based on binocular disparity cues: an fMRI study.

Cortical areas related to the information processing of binocular disparity-defined geometrical features of a surface, such as depth, orientation and shape are examined by functional magnetic resonance imaging while subjects discriminated these three types of geometrical feature in random dot stereograms. Results indicate that disparity-defined information of depth and that of orientation are processed in the parietal area. Furthermore, the visual system for 3D vision in the parietal area may be organized in a hierarchical manner and the posterior part of the right intraparietal sulcus may be involved in cognitive process of 3D vision. On the other hand, disparity-defined shape information seems to be processed in the occipital visual areas and the crucial involvement of human LOS for this process is suggested.

Adult↗

PubMed2002

Neural correlates for perception of 3D surface orientation from texture gradient.

A goal in visual neuroscience is to reveal how the visual system reconstructs the three-dimensional (3D) representation of the world from two-dimensional retinal images. Although the importance of texture gradient cues in the process of 3D vision has been pointed out, most studies concentrate on the neural process based on binocular disparity. We report the neural correlates of depth perception from texture gradient in the cortex. In the caudal part of the lateral bank of intraparietal sulcus, many neurons were selective to 3D surface orientation defined by texture gradient, and their response was invariant over different types of texture pattern. Most of these neurons were also sensitive to a disparity gradient, suggesting that they integrate texture and disparity gradient signals to construct a generalized representation of 3D surface orientation.

Animals↗

PubMed2002

Current perception threshold and sympathetic skin response in diabetic and alcoholic polyneuropathies.

OBJECTIVE: Correlation between current perception threshold and sympathetic skin response was investigated in patients with diabetic or alcoholic polyneuropathy. METHODS: Current perception threshold was measured using Neurometer CPT/C, and the sympathetic skin response was measured using Neuropack sigma. PATIENTS: Fourteen patients with diabetic polyneuropathy and 10 patients with alcoholic polyneuropathy were studied. RESULTS: There was a significant negative correlation between the current perception threshold to 5 Hz stimulation and the amplitude of sympathetic skin response. CONCLUSION: Since both current perception threshold to 5 Hz stimulation and sympathetic skin response are related to C fibers, these two are considered to be impaired concurrently in diabetic and alcoholic polyneuropathies.

Adrenergic Fibers↗