PubMed Health⌕ Search

Biomedical subjects

Teruko Uwano

Publications and source records attributed to Teruko Uwano.

11 recordsLinked to original sources
PubMed2005

Auditory thalamus integrates visual inputs into behavioral gains.

By binding multisensory signals, we get robust percepts and respond to our surroundings more correctly and quickly. How and where does the brain link cross-modal sensory information to produce such behavioral advantages? The classical role of sensory thalamus is to relay modality-specific information to the cortex. Here we find that, in the rat thalamus, visual cues influence auditory responses, which have two distinct components: an early phasic one followed by a late gradual buildup that peaks before reward. Although both bimodal presentation and reward value had similar effects on behavioral performance, the cross-modal effect on neural activity showed unique temporal dynamics: it affected the amplitude of the early component and starting level of the late component, whereas reward value affected only the slope of the late component. These results demonstrate that cross-modal cueing modulates gain in the sensory thalamus, potentially providing a priming influence on the choice of an optimal behavior.

Acoustic Stimulation↗
PubMed2005

Effects of prenatal maternal stress by repeated cold environment on behavioral and emotional development in the rat offspring.

It has been reported that many types of stresses, which caused physiological and psychological alterations in dams as prenatal maternal stress, affected behavioral and emotional traits of their offspring. However, effects of environmental temperature changes, which induce various stress responses in both animals and humans, have not been assessed as prenatal maternal stress. Repeated cold stress (RCS) is a type of chronic cold stress in which environmental temperature changes rapidly and frequently several times within a day. In the present study, to investigate effects of chronic maternal stress by the RCS on behavioral and emotional development of the rat offspring (prenatal RCS rats), the RCS stress was loaded to pregnant rats between day 9 and 19 after fertilization. The prenatal RCS rats showed similar locomotor activity in an open field to control rats that were borne by non-stressed pregnant rats. On the other hand, the prenatal RCS rats showed significantly higher startle responses than the control rats in a light enhanced startle paradigm. However, treatment of diazepam decreased the startle responses in the prenatal RCS rats to the same degree as those in the control rats. The results indicated that prenatal RCS affected emotional development of the rat offspring, but not locomotor activity. Comparison of the present results with the previous studies suggests that there might be unknown common mechanisms among different prenatal maternal stresses that induce similar behavioral developmental alteration.

Analysis of Variance↗
PubMed2005

Dopamine D1 receptors involved in locomotor activity and accumbens neural responses to prediction of reward associated with place.

Predicting reward is essential in learning approach behaviors. Dopaminergic activity has been implicated in reward, movement, and cognitive processes, all essential elements in learning. The nucleus accumbens (NAc) receives converging inputs from corticolimbic information-processing areas and from mesolimbic dopamine neurons originating in the ventral tegmental area. Previously, we reported that in mice, a dopamine D2 receptor knockout (D2R-KO) eliminated the prereward inhibitory response, increased place-field size of NAc neurons, and reduced locomotor activity without marked change in intracranial self-stimulation (ICSS) behavior. The present study investigated the specific contribution of dopamine D1 receptor (D1R) in mediating reward, locomotor activity, and spatial associative processes and in regulating NAc neural responses. In contrast to D2R-KO animals, here we find D1R-KO in mice selectively eliminated the prereward excitatory response and decreased place-field size of NAc neurons. Furthermore, D1R-KO impaired ICSS behavior, seriously reduced locomotor activity, and retarded acquisition of a place learning task. Thus, the present results suggest that D1R may be an important determinant in brain stimulation reward (ICSS) and participates in coding for a type of reward prediction of NAc neurons and in spatial learning.

Animals↗
PubMed2004

Effects of nonsaponin fraction of red ginseng on learning deficits in aged rats.

Previously we reported that oral application of red ginseng significantly ameliorated learning deficits in aged rats and young rats with hippocampal lesions. In the present study, we investigated the effects of the nonsaponin fraction of red ginseng on learning deficits in aged rats in behavioral studies and those on long-term potentiation (LTP) in the hippocampal CA3 subfield in young rats in electrophysiological studies. In the behavioral studies, three groups of rats [aged rats with and without oral administration of the nonsaponin fraction of red ginseng and young rats] were tested with the three types of spatial-learning task [distance movement task (DMT), random-reward place search task (RRPST), and place-learning task (PLT)] in a circular open field. The results in the DMT and RRPST indicated that motivational and motor activity was not significantly different among the three groups of rats. However, performance of the aged rats without nonsaponin was significantly impaired in the PLT when compared with the young rats. Treatment with nonsaponin significantly ameliorated deficits in place-navigation learning in the aged rats in the PLT. In the electrophysiological studies, effects of nonsaponin on the LTP in the CA3 subfield of the hippocampal slices were investigated in vitro. Pretreatment with nonsaponin significantly augmented the increase in population spike amplitudes in the CA3 subfield after LTP induction. These results suggest that the nonsaponin fraction of red ginseng contains important substances to improve learning and memory in aged rats and that this amelioration by nonsaponin might be attributed partly to augmentation of LTP in the CA3 subfield.

Aging↗
PubMed2004

Proof of the mysterious efficacy of ginseng: basic and clinical trials: effects of red ginseng on learning and memory deficits in an animal model of amnesia.

Ameliorating effects of red ginseng on learning and memory deficits due to hippocampal lesions and aging were reviewed; the performance of young rats with selective hippocampal lesions with or without red ginseng (p.o.), and aged rats with or without red ginseng (p.o.) in the spatial learning tasks was compared with that of sham-operated or intact young rats. Each rat was tested with 3 types of spatial learning tasks (distance movement task, DMT; random reward place search task, RRPST; and place learning task, PLT) in a circular open field using intracranial self-stimulation (ICSS) as reward. The results in the DMT and RRPST indicated that motivational and motor activity of young rats with hippocampal lesions with and without ginseng and aged rats with and without ginseng were not significantly different from that of control young rats. However, young rats with hippocampal lesions without ginseng and aged rats without ginseng displayed significant deficits in the PLT. Treatment with red ginseng significantly ameliorated place-navigation deficits in young rats with hippocampal lesions in the PLT. Similarly, red ginseng improved performance of aged rats in the PLT. The results, along with previous studies showing significant effects of red ginseng on the central nervous system, suggest that red ginseng ameliorates learning and memory deficits through effects on the central nervous system, partly through effects on the hippocampal formation. However, its mechanisms are still unclear, and further studies are required.

Aging↗
PubMed2003

Regulated transgene delivery by ganciclovir in the brain without physiological alterations by a live attenuated herpes simplex virus vector.

The distribution of a live attenuated herpes simplex virus (betaH1)-mediated gene delivery into the central nervous system (CNS) was regulated by growth inhibition with ganciclovir (GCV) and the effect of this transgene expression system on the physiologic response was characterized by the acoustic startle response and its prepulse inhibition. We inoculated betaH1 expressing beta-galactosidase (beta-gal) driven by the latency associated transcripts promoter into the right caudate putamen of rats. Histochemical analysis demonstrated that the inoculation of betaH1 in the right caudate putamen resulted in a high level of beta-gal expression in the neurons of the area projecting to the inoculation site. On 14 days after inoculation without GCV-treatment, beta-gal activity localized in the anterior olfactory nucleus, frontal, insular, orbital, parietal, perirhinal, piriform cortices and the temporal region including the amygdala. In contrast, the distribution of beta-gal activity was regulated by the interval between virus inoculation and GCV-treatment and maintained after its cessation without significant alteration. The whole process of transgene expression did not influence the emotional behavior, indicating that this vector system is a suitable model for analyzing the transgene function or applying the gene therapy for the CNS diseases.

Animals↗
PubMed2002

Altered accumbens neural response to prediction of reward associated with place in dopamine D2 receptor knockout mice.

Midbrain dopaminergic activity seems to be important in forming the prediction of future events such as rewards. The nucleus accumbens (NAc) plays an important role in the integration of reward with motor function, and it receives dense dopamine innervation and extensive limbic and cortical afferents. Here, we examined the specific role of the dopamine D2 receptor (D2R) in mediating associative learning, locomotor activity, and regulating NAc neural responses by using D2R-knockout (KO) mice and their wild-type littermates. D2R-KO mice displayed reduced locomotor activity and slower acquisition of a place-learning task. D2R-KO eliminated the prereward inhibitory response of neurons in the NAc. In contrast, an increased number of neurons in D2R-KO mice displayed place-related activity. These results provide evidence that D2R in the NAc participates in coding for a specific type of neural response to incentive contingencies and partly in spatial learning.

Animals↗
PubMed2002

Effects of a novel arginine-vasopressin derivative, NC-1900, on the spatial memory impairment of rats with transient forebrain ischemia.

NC-1900, an arginine-vasopressin derivative, has been reported to enhance memory for avoidance behavior. Specifically, NC-1900 ameliorated cycloheximide-induced learning impairments in a passive avoidance test in rats. In the present study, we investigated that effects of NC-1900 on place learning in rats with selective lesions in the CA1 subfield of the hippocampal formation produced by transient forebrain ischemia. NC-1900 was administered daily (1 microg/kg, p.o.) 1 h before the place learning task. A rat was required to alternate between 2 small circular areas located diametrically opposite each other on the circumference of an open field in order to obtain intracranial electrical stimulation reward (the spatial navigation task). Rats with hippocampal lesions showed severe place learning impairments both in task performance (indicated by number of rewards obtained per a session) and in navigation performance (forming efficient trails) over the 30-day test period. Treatment with NC-1900 ameliorated deficits in the place learning exhibited by rats with the same hippocampal lesions, such that their performance reached normal levels. There were no significant differences in the ischemic hippocampal lesions, spontaneous locomotor activity, and stimulation current intensity between the treated and untreated rats. The results demonstrated that NC-1900 reduced place learning impairments produced by hippocampal lesions.

Amnesia↗
PubMed2002

Neuronal responses of the rat amygdala during extinction and reassociation learning in elementary and configural associative tasks.

To investigate functional heterogeneity within the amygdala in appetitive conditioned instrumental behaviours, neuronal activity was recorded from the amygdala of behaving rats during learning and discrimination of conditioned sensory stimuli associated with or without reinforcement [sucrose solution, intracranial self-stimulation (ICSS)]. Sensory stimuli included auditory (tone), visual (light) and configural (simultaneous presentation of tone and light) stimuli. The rat was trained to lick a spout protruded close to its mouth just after a conditioned sensory stimulus to obtain a reward. Of the 609 neurons recorded from the amygdala and amygdalostriatal transition area, 154 responded to one or more sensory stimuli. The 62 amygdalar neurons responded strongly to certain conditioned sensory stimuli associated with rewards. Of these 62 neurons, 45 were tested with the extinction trials. Responses of 31 neurons to conditioned stimuli were finally extinguished, and those of the remaining 14 were not extinguished. Furthermore, responses of 26 of these 31 neurons resumed in the relearning trials (plastic neurons), suggesting that these sensory responses were associative rather than just responses to physical properties of the stimuli. These plastic neurons were located mainly in the basolateral nucleus of the amygdala, and responses of the plastic neurons were correlated with behavioural responses. These results suggest that the basolateral nucleus is crucial in associative learning between sensory information and affective significance for behavioural outputs in appetitive conditioned instrumental behaviours.

Acoustic Stimulation↗
PubMedDate not supplied

Comparison of brain activity between dopamine D2 receptor-knockout and wild mice in response to dopamine agonist and antagonist assessed by fMRI.

It has been reported that antipsychotic dopamine-D2-receptor (D2R) antagonists affected other neurotransmitter systems. In the present study, the effects of a D2R agonist, bromocriptine, and a D2R antagonist, spiperone, on brain activity were investigated using wild-type mice (WT) with intact D2Rs, and D2R-knockout mice (D2R-KO) lacking D2Rs by functional magnetic resonance imaging. In the WT, flow-weighted signal intensity significantly increased after administration of bromocriptine in the hippocampal formation. In contrast, signal intensity significantly decreased after administration of spiperone in the somatosensory-motor cortices, thalamus, anterior cingulate cortex, caudate-putamen, nucleus accumbens, hippocampal formation, and amygdala. In the D2R-KO, however, no significant changes were observed after administration of either bromocriptine or spiperone. The present results indicated that the D2R-KO lacked sensitivity to D2R agonist and antagonist in agreement with its genetic defects, which confirmed that the changes in brain activity in the WT after administration of either drug were mediated through D2Rs. These results suggest that antipsychotic D2R antagonists affect activity of the same brain regions of human patients through D2Rs, as observed in the present study. These changes in brain activity might be related to therapeutic efficacy as well as side effects of antipsychotic drugs on schizophrenic patients.

Animals↗