Absolute pitch and pupillary response: effects of timbre and key color

The pitch identification performance of absolute pitch possessors has previously been shown to depend on pitch range, key color, and timbre of presented tones. In the present study, the dependence of pitch identification performance on key color and timbre of musical tones was examined by analyzing hit rates, reaction times, and pupillary responses of absolute pitch possessors (n = 9) and nonpossessors (n = 12) during a pitch identification task. Results revealed a significant dependence of pitch identification hit rate but not reaction time on timbre and key color in both groups. Among absolute pitch possessors, peak dilation of the pupil was significantly dependent on key color whereas the effect of timbre was marginally significant. Peak dilation of the pupil differed significantly between absolute pitch possessors and nonpossessors. The observed effects point to the importance of learning factors in the acquisition of absolute pitch.     

宫内缺氧对新生小鼠额叶皮质神经元内nNOS表达及对成年小鼠学习记忆能力的影响

为探讨孕鼠宫内缺氧对新生小鼠发育时期额叶皮质神经元内nNOS表达及对成年小鼠学习记忆能力的影响,本研究采用Tapanainen建立的缺氧模型致胎龄13、15、17d小鼠宫内缺氧,然后采用Nissl染色观察新生鼠发育时期P1、P7、P14、P28、P90额叶皮质内神经元的数量和形态变化;免疫组织化学染色方法观察新生鼠发育时期P1、P7、P14、P28、P90脑组织内nNOS阳性神经元的表达;Morris水迷宫实验检测P90小鼠的学习和记忆能力。结果显示:与正常组比较,宫内缺氧组小鼠额叶皮质神经元数量明显减少,额叶皮质神经元内nNOS的表达明显减弱。宫内缺氧组小鼠逃避潜伏期延长及穿环次数明显减少。以上结果提示宫内缺氧可导致新生鼠额叶皮质神经元数量明显减少及nNOS的表达也明显减弱,并引起成年小鼠学习记忆能力降低。     

Functional relation between corticonuclear input and movements evoked on microstimulation in cerebellar nucleus interpositus anterior in the cat

The functional relation between receptive fields of climbing fibres projecting to the C1, C3 and Y zones and forelimb movements controlled by nucleus interpositus anterior via the rubrospinal tract were studied in cats decerebrated at the pre-collicular level. Microelectrode tracks were made through the caudal half of nucleus interpositus anterior. This part of the nucleus receives its cerebellar cortical projection from the forelimb areas of these three sagittal zones. The C3 zone has been demonstrated to consist of smaller functional units called microzones. Natural stimulation of the forelimb skin evoked positive field potentials in the nucleus. These potentials have previously been shown to be generated by climbing fibre-activated Purkinje cells and were mapped at each nuclear site, to establish the climbing fibre receptive fields of the afferent microzones. The forelimb movement evoked by microstimulation at the same site was then studied. The movements usually involved more than one limb segment. Shoulder retraction and elbow flexion were frequently evoked, whereas elbow extension was rare and shoulder protraction never observed. In total, movements at the shoulder and/or elbow occurred for 96% of the interpositus sites. At the wrist, flexion and extension movements caused by muscles with radial, central or ulnar insertions on the paw were all relatively common. Pure supination and pronation movements were also observed. Movements of the digits consisted mainly of dorsal flexion of central or ulnar digits. A comparison of climbing fibre receptive fields and associated movements for a total of 110 nuclear sites indicated a general specificity of the input-output relationship of this cerebellar control system. Several findings suggested that the movement evoked from a particular site would act to withdraw the area of the skin corresponding to the climbing fibre receptive field of the afferent microzones. For example, sites with receptive fields on the dorsum of the paw were frequently associated with palmar flexion at the wrist, whereas sites with receptive fields on the ventral side of the paw and forearm were associated with dorsiflexion at the wrist. Correspondingly, receptive fields on the lateral side of the forearm and paw were often associated with flexion at the elbow, whereas sites with receptive fields on the radial side of the forearm were associated with elbow extension. The proximal movements that were frequently observed also for distal receptive fields may serve to produce a general shortening of the limb to enhance efficiency of the withdrawal. It has previously been suggested that the cerebellar control of forelimb movements via the rubrospinal tract has a modular organisation. Each module would consist of a cell group in the nucleus interpositus anterior and its afferent microzones in the C1, C3 and Y zones, characterised by a homogenous set of climbing fibre receptive fields. The results of the present study support this organisational principle, and suggest that the efferent action of a module is to withdraw the receptive field from an external stimulus. Possible functional interpretations of the action of this system during explorative and reaching movements are discussed.     

Hippocampal neuron and synaptophysin-positive bouton number in aging C57BL/6 mice

A loss of hippocampal neurons and synapses had been considered a hallmark of normal aging and, furthermore, to be a substrate of age-related learning and memory deficits. Recent stereological studies in humans have shown that only a relatively minor neuron loss occurs with aging and that this loss is restricted to specific brain regions, including hippocampal subregions. Here, we investigate these age-related changes in C57BL/6J mice, one of the most commonly used laboratory mouse strains. Twenty-five mice (groups at 2, 14, and 28–31 months of age) were assessed for Morris water-maze performance, and modern stereological techniques were used to estimate total neuron and synaptophysin-positive bouton number in hippocampal subregions at the light microscopic level. Results revealed that performance in the water maze was largely maintained with aging. No age-related decline was observed in number of dentate gyrus granule cells or CA1 pyramidal cells. In addition, no age-related change in number of synaptophysin-positive boutons was observed in the molecular layer of the dentate gyrus or CA1 region of hippocampus. We observed a significant correlation between dentate gyrus synaptophysin-positive bouton number and water-maze performance. These results demonstrate that C57BL/6J mice do not exhibit major age-related deficits in spatial learning or hippocampal structure, providing a baseline for further study of mouse brain aging.     

The Effects of Discrimination Training on Voluntary Control of Cephalic Vasomotor Activity

The present study was conducted to test Brener's calibration theory of visceral learning. It was hypothesized that training in discrimination of cephalic vasomotor responses would enhance acquisition of voluntary and biofeedback control of cephalic vasomotor response. Four groups were given discrimination training to detect either constriction, dilation, both constriction and dilation, or given false feedback. All groups were then given biofeedback training in constriction. All groups were assessed on discrimination accuracy, acquisition of biofeedback control of constriction, and voluntary control of dilation and constriction. The results indicated that discrimination of cephalic vasomotor responses can be learned and that this skill facilitates the acquisition of biofeedback and voluntary control of vasomotor responses. This facilitation occurs only if discrimination training is given for the specific response to be learned. The data suggest that discrimination of the relevant response is a necessary but not sufficient condition for acquisition of voluntary control in biofeedback learning.     

Nonlinearity identified by neural network models inP CO 2 control system in humans

The nonlinearity included in the P_{CO 2} control system in humans is evaluated using the degree of nonlinearity based on a difference of residuals. An autoregressive moving average (ARMA) model and neural networks (linear and nonlinear) are employed to model the system, and three types of network (Jordan, Elman and fully interconnected) are compared. As the Jordan-type linear network cannot approximate respiratory data accurately, the other two types and the ARMA model are used for the evaluation of the nonlinearity. The results of the evaluation indicate that the linear assumption for the P_{CO 2} control system is invalid for three subjects out of seven. In particular, strong nonlinearity was observed for two subjects.     

Hand and joint paths during reaching movements with and without vision

 This study examines whether the kinematics of pointing movements are altered by the sensory systems used to select spatial targets and to guide movement. Hand and joint paths of visually guided reaching movements of human subjects were compared with two non-visual conditions where only proprioception was available: (1) movements of the same subjects with blindfolds, and (2) movements by congenitally blind subjects. While hand-path curvatures were overall quite small, sighted subjects wearing a blindfold showed a statistical increase in hand-path curvature compared with their visually guided movements. Blindfolded subjects also showed greater hand-path curvature than blind subjects. These increases in hand-path curvature for blindfolded subjects did not always lead to a decrease in joint-path curvature. While there were differences between blind subjects and sighted subjects using vision for some movement directions, there was no systematic difference between these two groups. The magnitude of joint-path curvature showed much greater variation than hand-path curvature across the movement directions. We found variation in joint-path curvature to be correlated to two factors, one spatial and one geometrical. For all subject groups, joint-path curvature tended to be smaller for sagittal-plane movements than for transverse or diagonal movements. As well, we found that the magnitude of joint-path curvature was also related to the relative motion at each joint. Joint-path curvature tended to increase when movements predominantly involved changes in shoulder angle and was minimal when movements predominantly involved elbow motion. The consistently small curvatures of hand trajectory across blind and sighted subjects emphasize the powerful tendency of the motor system to generate goal-directed reaching movements with relatively straight hand trajectories, even when deprived of visual feedback from very early in life. Received: 16 July 1997 / Accepted: 20 May 1998     

Enhancement of an inhibitory input to the feeding central pattern generator in Lymnaea stagnalis during conditioned taste-aversion learning

To study the neuronal mechanism of a conditioned taste-aversion (CTA) learning in the pond snail Lymnaea stagnalis, we examined the synaptic connection between the neuron 1 medial (N1M) cell and the cerebral giant cell (CGC), the former is an interneuron in central pattern generator for the feeding response and the latter is a regulatory neuron to the central pattern generator. Inhibitory postsynaptic potential (IPSP) which was evoked in the N1M cell by activation of the CGC was larger and lasted longer in the conditioned animal than that in the control animal. The electrical properties of the cell body of CGC and the responses of the CGC to the chemosensory inputs were not changed during the CTA learning. These results, together with the previous report indicating the existence of excitatory projection from the N1M cell to the feeding motoneuron, suggest that enhanced IPSP in the N1M cell may underlie the suppression of feeding responses in the Lymnaea CTA learning.     

Psychoemotional manifestations in hippocampectomized rats

The effects of lesioning of the dorsal hippocampus on the psychoemotional state of Wistar rats were studied. Hippocampal lesions did not affect the learning process, but affected mainly the pattern of psychoemotional manifestations in all animals regardless of the typology of higher nervous activity. All animals showed reductions in the extremes of types of passive and active stress reactions. Individual effects depended on the behavioral phenotypes of the animals. Hippocampal lesions in rapidly learning rats (10%) led to sharp decreases in irritability (active/passive = 0.35/0.5 instead of 1.0/0.4), while passive-defensive manifestations were not altered. In slowly learning animals (30%), hippocampal lesions were not accompanied by qualitative changes in the patterns of psychoemotional manifestations, while non-learning rats (60%) showed decreases in passive and increases in active manifestations (active/passive = 0.45/1.4 instead of 0.3/1.9). It is suggested that the hippocampus is involved in producing psychoemotional reactions, individual patterns of which depend on the morphofunctional characteristics of the system responsible for organizing the psychoemotional state.Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 89, No. 7, pp. 868–878, July, 2003.