Knockout crickets for the study of learning and memory : Dopamine receptor Dop1 mediates aversive but not appetitive reinforcement in crickets

Elucidation of reinforcement mechanisms in associative learning is an important subject in neuroscience. In mammals, dopamine neurons are thought to play critical roles in mediating both appetitive and aversive reinforcement. Our pharmacological studies suggested that octopamine and dopamine neurons mediate reward and punishment, respectively, in crickets, but recent studies in fruit-flies concluded that dopamine neurons mediates both reward and punishment, via the type 1 dopamine receptor Dop1. To resolve the discrepancy between studies in different insect species, we produced Dop1 knockout crickets using the CRISPR/Cas9 system and found that they are defective in aversive learning with sodium chloride punishment but not appetitive learning with water or sucrose reward. The results suggest that dopamine and octopamine neurons mediate aversive and appetitive reinforcement, respectively, in crickets. We suggest unexpected diversity in neurotransmitters mediating appetitive reinforcement between crickets and fruit-flies, although the neurotransmitter mediating aversive reinforcement is conserved. This study demonstrates usefulness of the CRISPR/Cas9 system for producing knockout animals for the study of learning and memory

Immunocytochemical localization of amines and GABA in the optic lobe of the Butterfly, Papilio xuthus

Butterflies have sophisticated color vision. While the spectral organization of the compound eye has been well characterized in the Japanese yellow swallowtail butterfly, Papilio xuthus, neural mechanisms underlying its color vision are largely unexplored. Towards a better understanding of signal processing in the visual system of P. xuthus, we used immunocytochemical techniques to analyze the distribution of transmitter candidates, namely, histamine, serotonin, tyramine and γ-aminobutyric acid (GABA). Photoreceptor terminals in the lamina and medulla exhibited histamine immunoreactivity as demonstrated in other insects. The anti-histamine antiserum also labeled a few large medulla neurons. Medulla intrinsic neurons and centrifugal neurons projecting to the lamina showed serotonin immunoreactivity. Tyramine immunostaining was detected in a subset of large monopolar cells (LMCs) in the lamina, transmedullary neurons projecting to the lobula plate, and cell bodies surrounding the first optic chiasma. An anti-GABA antiserum labeled a subset of LMCs and populations of columnar and tangential neurons surrounding the medulla. Each of the four antisera also labeled a few centrifugal neurons that innervate the lobula complex from the central brain, suggesting that they have neuromodulatory roles. A distinctive feature we found in this study is the possibility that tyramine and GABA act as transmitters in LMCs of P. xuthus, which has not been reported in any other insects so far

Roles of OA1 octopamine receptor and Dop1 dopamine receptor in mediating appetitive and aversive reinforcement revealed by RNAi studies

Revealing reinforcing mechanisms in associative learning is important for elucidation of brain mechanisms of behavior. In mammals, dopamine neurons are thought to mediate both appetitive and aversive reinforcement signals. Studies using transgenic fruit-flies suggested that dopamine neurons mediate both appetitive and aversive reinforcements, through the Dop1 dopamine receptor, but our studies using octopamine and dopamine receptor antagonists and using Dop1 knockout crickets suggested that octopamine neurons mediate appetitive reinforcement and dopamine neurons mediate aversive reinforcement in associative learning in crickets. To fully resolve this issue, we examined the effects of silencing of expression of genes that code the OA1 octopamine receptor and Dop1 and Dop2 dopamine receptors by RNAi in crickets. OA1-silenced crickets exhibited impairment in appetitive learning with water but not in aversive learning with sodium chloride solution, while Dop1-silenced crickets exhibited impairment in aversive learning but not in appetitive learning. Dop2-silenced crickets showed normal scores in both appetitive learning and aversive learning. The results indicate that octopamine neurons mediate appetitive reinforcement via OA1 and that dopamine neurons mediate aversive reinforcement via Dop1 in crickets, providing decisive evidence that neurotransmitters and receptors that mediate appetitive reinforcement indeed differ among different species of insects

From University to Work III Part 2 : How Students seek for ""Good Jobs"" in Non-Selective 4-Year-Colleges

This is the second report using the same survey data for non-selective college students in business major. In this report, we analyze the process of students\u27job seeking activities. We find that the timing and kinds of job seeking activities among those students are more diverse and less standardized than those from selective colleges. This less standardized feature of activities makes the process of job search for those non-selective college students more vague and more difficult. As a result, we also find that there are students, who stop or never start job seeking

Career Choice among General High School Students in Urban Cities : A Survey of Students with No Jobs No Colleges

Recent national statistics show that about 10% of new high school graduates don\u27t have any jobs or college education after high school; they are called MUGYOSHA in Japanese. Especially in urban areas, students from lower ranked general high schools tend to be those MUGYOSHA. Many of those students don\u27t commit themselves to any activities to seek for jobs or college education after graduation. Why are they inactive in exploring their future careers? How do they perceive their own "aptitude and ability"? How is their career consciousness structured? What experiences they have in and out of school influence their career perspectives? Based on questionnaire survey of 1098 high school students in 11 general high schools in the Tokyo Metropolitan area, we pursue those questions. We obtain the following findings. 1. Students career consciousness is structured with 6 elements, and the main three elements are present-orientation, understanding own aptitude, and commitment to meritocratic values. 2. School\u27s career guidance activities have little impact on those elements of career consciousness, although students outside school life have much influence on them. 3. Students\u27family background influences formation of career consciousness, and final careers, by restricting students\u27chances to enter colleges. 4. After controlling such other variables as gender, grades, economic family background, and high school rank, those three main elements of career consciousness have independent effects on students\u27chance to be MUGYOSHA. According to those findings, we discuss that with limited resources to socialize students into jobs, lower ranked general high schools face difficulties to help students find their own future career, under strong values of self-decision and self-responsibility of new-liberal education reforms

Kanji-Limited Pure Alexia : A Case Report and the Problem of Variability in Pure Alexia

A case of Kanji-limited pure alexia has been reported. Concomitantly, we have examined another five pure alexic patients, administering the same liguistic test battery in order to compare the variability of disturbances in reading ability. It is concluded that the first case reported in detail may represent a pure example of categorization or global reading deficit. We suppose our six cases of pure alexic patients may classified into three types as follows. Type I : Alexia is mild or moderate and in which letter-by-letter or analytical reading strategy might be predominant. Type II: Alexia is similarly mild or moderate but in which global reading strategy might be predominant. Type III: Degree of alexia is so severe that we could not judge the dominant reading strategy, or in other words, neither analytical nor global reading strategy could be used well

Tyrosine hydroxylase-immunoreactive neurons in the mushroom body of the field cricket, Gryllus bimaculatus

The mushroom body of the insect brain participates in processing and integrating multimodal sensory information and in various forms of learning. In the field cricket, Gryllus bimaculatus, dopamine plays a crucial role in aversive memory formation. However, the morphologies of dopamine neurons projecting to the mushroom body and their potential target neurons, the Kenyon cells, have not been characterized. Golgi impregnations revealed two classes of Kenyon cells (types I and II) and five different types of extrinsic fibers in the mushroom body. Type I cells, which are further divided into two subtypes (types I core and I surface), extend their dendrites into the anterior calyx, whereas type II cells extend many bushy dendritic branches into the posterior calyx. Axons of the two classes bifurcate between the pedunculus and lobes to form the vertical, medial and lobes. Immunocytochemistry to tyrosine hydroxylase (TH), a rate-limiting enzyme in dopamine biosynthesis, revealed the following four distinct classes of neurons: (1) TH-SLP projecting to the distal vertical lobe; (2) TH-IP1 extending to the medial and lobes; (3) TH-IP2 projecting to the basal vertical lobe; and (4) a multiglomerular projection neuron invading the anterior calyx and the lateral horn (TH-MPN). We previously proposed a model in the field cricket in which the efficiency of synapses from Kenyon cells transmitting a relevant sensory stimulus to output neurons commanding an appropriate behavioral reaction can be modified by dopaminergic neurons mediating aversive signals and here, we provide putative neural substrates for the cricket's aversive learning. These will be instrumental in understanding the principle of aversive memory formation in this model species

Tentative de démembrement de l'apraxie bucco-faciale.

The authors have studied the bucco-facial apraxia (BFA) in 28 aphasic patients, examining 10 isolated oral gestures (IOG) and 10 combined oral gestures (COG). The heterogeneity of the BFA is indicated by the qualitative analysis of the types of errors in COG in relation to IOG. It is probable that the BFA due to posterior lesions is related to the motor programming disorders of oral gestures, and that the BFA due to anterior lesions to the motor realization disorders of oral gestures. It remains uncertain as to whether there is a continuity or some varieties between these two types of BFA

Paraphasia and Related Disorders in Primary Degenerative Dementia.

A confrontation naming task administered to 12 cases of primary degenerative dementia resulted in (1) semantic verbal paraphasia exhibiting a rather consistent tendency to occur in cases with mild word finding difficulty, whereas semantically unrelated paraphasia was produced in cases with almost every grade of severity of naming impairment. (2) The portion occupied by verbal paraphasia as a whole in the total quantity of speech output tended rather to diminish in proportion of naming difficulty in favour of increasing amount of empty pharases, circumlocutions, and commenting speech. (3) About half of the cases exhibited a remarkable naming behaviour in word finding with aid of the initial syllable of a target word given as an auditory cue, producing a definite amount of phonemic paraphasia (often neologism) and formal nominal aphasia that were only exceptionally observed in 2 representative cases of fluent aphasia of vascular origin whereas in simple naming (without cue) predominantly verbal paraphasia was elicited in both groups. It suggests a hitherto unnoticed qualitative difference, probably in the phonological aspect, of word finding difficulty between dementia patients and aphasics with focal brain damage