Dorsolateral Portion Research Articles

Evidence of the Existence of Site-Specific Female Contact Pheromones Involved in the Sexual Interaction Behavior of the Pacific Whiteleg Shrimp Penaeus vannamei.

Although the presence of female contact sex pheromones in P. vannamei has been hypothesized, to date its existence has not been proven. To gather more evidence of their existence, cuticular liposoluble extracts were obtained from the following samples of adult females to be used as the experimental treatments: (1) ventral exoskeleton of immature female (VI), (2) dorsolateral exoskeleton of immature female (DI), (3) ventral exoskeleton of mature female (VM), and (4) dorsolateral exoskeleton of mature female (DM). Polyvinyl chloride tubes (artificial females; AF) were coated with each extract and the behavior displayed by sexually mature males in contact with the AF was recorded and classified as follows: 0 = no response; 1 = contact; 2 = pushing; and 3 = prolonged contact (≥10 s). To test the hypothesis that the extracts collected from the ventral portion of the abdomen exoskeleton have a higher effect on the behavior of males than the extracts collected from the dorsolateral portion of the abdomen exoskeleton, the experiment was divided into two bioassays: Bioassay I (VI vs. DI) and Bioassay II (VM vs. DM). In each bioassay, all experimental treatments were significantly different (p > 0.05) from the CTL group (AF coated with hexane). Notably, the pushing behavior was significantly higher (p < 0.05) in the VI treatment compared to the CTL and DI treatment. These results provide evidence of the existence of contact female sex pheromones with sexual recognition function located primarily in the ventral portion of the abdomen exoskeleton of P. vannamei.

The neural basis of naturalistic semantic and social cognition

Decoding social environments and engaging meaningfully with other people are critical aspects of human cognition. Multiple cognitive systems, including social and semantic cognition, work alongside each other to support these processes. This study investigated shared processing between social and semantic systems using neuroimaging data collected during movie-viewing, which captures the multimodal environment in which social knowledge is exchanged. Semantic and social content from movie events (event-level) and movie transcripts (word-level) were used in parametric modulation analyses to test (1) the degree to which semantic and social information is processed within each respective network and (2) engagement of the same cross-network regions or the same domain-general hub located within the semantic network during semantic and social processing. Semantic word and event-level content engaged the same fronto-temporo-parietal network and a portion of the semantic hub in the anterior temporal lobe (ATL). Social word and event-level content engaged the supplementary motor area and right angular gyrus within the social network, but only social words engaged the domain-general semantic hub in left ATL. There was evidence of shared processing between the social and semantic systems in the dorsolateral portion of right ATL which was engaged by word and event-level semantic and social content. Overlap between the semantic and social word and event results was highly variable within and across participants, with the most consistent loci of overlap occurring in left inferior frontal, bilateral precentral and supramarginal gyri for social and semantic words and in bilateral superior temporal gyrus extending from ATL posteriorly into supramarginal gyri for social and semantic events. These results indicate a complex pattern of shared and distinct regions for social and semantic cognition during naturalistic processing.Protocol registrationThe stage 1 protocol for this Registered Report was accepted in principle on October 11, 2022. The protocol, as accepted by the journal, can be found at: https://doi.org/10.17605/OSF.IO/ACWQY.

Antillean manatee (Trichechus manatus manatus Linnaeus, 1758) Tongue Morphology and Adaptive Herbivorous Implications.

Morphological study of the tongue is an interesting way of understanding evolutionary processes associated with feeding habits. Therefore, the aim of the present study was to describe the tongue morphology of the Antillean manatee and to understand possible morphological relationships with its way of capturing food. Macroscopic dissections and light and scanning electron microscopy analyses of seven manatee tongues were performed. The tongue in Antillean manatees is a muscular and robust organ, divided into apex, body, and root. It is firmly adhered to the floor of the oral cavity. Lingual papillae were distributed over the entire tongue surface. They were identified as filiform papillae concentrated in the apex. Fungiform papillae were present on the apex and lateral regions. Foliate papillae were located on the dorsolateral portion of the root. Lentiform papillae were located across the dorsal tongue surface. The mucosa was lined by a keratinized stratified squamous epithelium presenting compound tubuloacinar glands and taste buds in the foliate papillae. The tongue of the Antillean manatee is similar to other Sirenia species, both of which share a completely herbivorous diet.

PAllidal versus SubThalamic deep brain Stimulation for Cervical Dystonia (PASTS-CD): study protocol for a multicentre randomised controlled trial

IntroductionDeep brain stimulation (DBS) has been validated as a safe and effective treatment for refractory cervical dystonia (CD). Globus pallidus internus (GPi) and subthalamic nucleus (STN) are the two main...

Pesticide residues detected in Colossoma macropomum by the modified QuEChERS and GC-MS/MS methods

This study aimed to detect pesticides in the muscle tissue of farmed tambaqui (Colossoma macropomum), in relation to good management practices (GMP) and prophylaxis and biosecurity measures. There were 54 fish farms randomly selected from the 138 found in the Microregion of Zona da Mata, RO - Brazil, for visits and collection of epidemiological data. There were extracted 24 muscle fragments were extracted from dorsolateral portion of the tail of five specimens tambaqui per fish farming. The methods of detection and quantification of pesticide residues were modified QuEChERS and GC-MS/MS. Most fish farms are small businesses and their production areas are smaller than a rural module. These ventures are an income alternative for rural producers, this information is confirmed in percentage of 88.89% (48/54) of the rural properties visited have livestock and agriculture as their main productive activity. Water monitoring was carried out in 70.37% of fish farms. However, with frequency of two water analyzes per year. Preventive and prophylactic measures taken were performed in 30% (17/54). In addition, 7% (4/54) of fish farmers reported using sodium chloride and/or using formalin as a secondary preventive measure. It is also important to mention that there was a report of administration of potassium permanganate in a fish farm, 2% (1/54). There were 12.49% (3/54) positive for at least one pesticide. The chemical compounds found Azosxystrobin (&lt;LOQ), Epoxiconazole (&lt;LOQ) and Chlorpyrifos (&lt;LOQ). The presence of Azosxystrobin, Epoxiconazol and Chlorpyrifos in tambaqui muscle tissue samples was detected above acceptable limits by the PNCRC.

Role of nitric oxide on defensive behavior and long-term aversive learning induced by chemical stimulation of the dorsolateral periaqueductal gray matter

The midbrain periaqueductal gray matter, especially the dorsolateral portion (dlPAG), coordinates immediate defensive responses (DR) to threats, but also ascends forebrain information for aversive learning. The synaptic dynamics in the dlPAG regulate the intensity and type of behavioral expression, as well as long-term processes such as memory acquisition, consolidation, and retrieval. Among several neurotransmitters and neural modulators, nitric oxide seems to play an important regulatory role in the immediate expression of DR, but it remains unclear if this gaseous on-demand neuromodulator contributes to aversive learning. Therefore, the role of nitric oxide in the dlPAG was investigated, during conditioning in an olfactory aversive task. The behavioral analysis consisted of freezing and crouch-sniffing in the conditioning day after glutamatergic NMDA agonist injection into the dlPAG. Two days later, rats were re-exposed to the odor cue and avoidance was measured. 7NI, a selective neuronal nitric oxide synthase inhibitor (40 and 100 nmol), injected before NMDA (50 pmol) impaired immediate DR and consequent aversive learning. The scavenging of extrasynaptic nitric oxide by C-PTIO (1 and 2 nmol) induced similar results. Moreover, spermine NONOate, a nitric oxide donor (5, 10, 20, 40, and 80 nmol), produced DR by itself, but only the low dose also promoted learning. The following experiments utilized a fluorescent probe, DAF-FM diacetate (5 µM), directly into the dlPAG, to quantify nitric oxide in the three previous experimental situations. Nitric oxide levels were increased after NMDA stimulation, decreased after 7NI, and increased after spermine NONOate, in line with alterations in defensive expression. Altogether, the results indicate that nitric oxide plays a modulatory and decisive role in the dlPAG regarding immediate DR and aversive learning.

Image-Guided Stereotactic Radiosurgery for the Treatment of Spasticity and Pain: A Preliminary Experience.

BackgroundSpasticity is a major health problem worldwide. Response to current medical and rehabilitation treatments is often poor. Surgical treatment is available only for a very limited number of patients.AimWe recently reported the application of stereotactic radiosurgery as a treatment option for spasticity and related pain. This paper describes a larger experience using image-guided stereotactic radiosurgery targeting the cervical or lumbar spinal roots to relieve spasticity and pain in four patients.MethodsAll the patients had refractory spasticity and related pain, one patient had additional paroxystic neuralgic pain. The cause of spasticity and pain was a traumatic brain and/or spinal cord injury, brain and/or spinal cord surgery, and stroke. Symptoms affected the right superior limb in one patient, and the inferior limbs in three patients (unilaterally in two, bilaterally in one). According to the symptoms, one patient was treated at the cervical level (C7 right sensory root) and three patients at lumbar level (right L4, left S1, and L2 roots bilaterally). The target was selected on constructive interference in steady-state (CISS) MR, focusing the irradiation on the postganglionic sensory segment of the cervical root or the intra-foraminal dorsolateral sensory portion of the lumbar roots. Appropriate spasticity and pain scales were used to assess the patient’s status after the treatment.ResultsThe treatments were tolerated well. Marked symptomatic relief was found in all the treated patients. Improvements in spasticity and pain scales were observed up to the latest follow-up. After 2 years, the mean reduction of the visual analog scale (VAS) and Modified Ashworth Scale (MAS) was 64.3% and 43.7%, respectively, while the median reduction of MAS score was 50%.ConclusionsExcept for a previous case report, this is the first study describing a novel noninvasive technique based on image-guided radiosurgery to treat severe spasticity and pain due to brain and spinal cord injury. This novel technique appears to be safe and effective and deserves to be studied further.

Subregion-Specific Regulation of Dopamine D1 Receptor Signaling in the Striatum: Implication for L-DOPA-Induced Dyskinesia.

The striatum is the main structure of the basal ganglia. The striatum receives inputs from various cortical areas, and its subregions play distinct roles in motor and emotional functions. Recently, striatal maps based on corticostriatal connectivity and striosome-matrix compartmentalization were developed, and we were able to subdivide the striatum into seven subregions. Dopaminergic modulation of the excitability of medium spiny neurons (MSNs) is critical for striatal function. In this study, we investigated the functional properties of dopamine signaling in seven subregions of the striatum from male mice. By monitoring the phosphorylation of PKA substrates including DARPP-32 in mouse striatal slices, we identified two subregions with low D1 receptor signaling: the dorsolateral portion of the intermediate/rostral part (DL-IR) and the intermediate/caudal part (IC). Low D1 receptor signaling in the two subregions was maintained by phosphodiesterase (PDE)10A and muscarinic M4 receptors. In an animal model of 6-hydroxydopamine (6-OHDA)-induced hemi-parkinsonism, D1 receptor signaling was upregulated in almost all subregions including the DL-IR, but not in the IC. When L-DOPA-induced dyskinesia (LID) was developed, D1 receptor signaling in the IC was upregulated and correlated with the severity of LID. Our results suggest that the function of the striatum is maintained through the subregion-specific regulation of dopamine D1 receptor signaling and that the aberrant activation of D1 receptor signaling in the IC is involved in LID. Future studies focusing on D1 receptor signaling in the IC of the striatum will facilitate the development of novel therapeutics for LID.SIGNIFICANCE STATEMENT Recent progress in striatal mapping based on corticostriatal connectivity and striosome-matrix compartmentalization allowed us to subdivide the striatum into seven subregions. Analyses of D1 receptor signaling in the seven subregions identified two unique subregions with low D1 receptor signaling: the dorsolateral portion of the intermediate/rostral part (DL-IR) and the intermediate/caudal part (IC). Aberrant activation of D1 receptor signaling in the IC is involved in L-DOPA-induced dyskinesia (LID). Previous studies of LID have mainly focused on the DL-IR, but not on the IC of the striatum. Future studies to clarify aberrant D1 receptor signaling in the IC are required to develop novel therapeutics for LID.

Regulation of Energy Expenditure by Brainstem GABA Neurons

Homeostatic control of core body temperature is essential for survival. Temperature is sensed by specific neurons, in turn eliciting both behavioral (i.e., locomotion) and physiologic (i.e., thermogenesis, vasodilatation) responses. Here, we report that a population of GABAergic (Vgat-expressing) neurons in the dorsolateral portion of the dorsal raphe nucleus (DRN), hereafter DRNVgat neurons, are activated by ambient heat and bidirectionally regulate energy expenditure through changes in both thermogenesis and locomotion. We find that DRNVgat neurons innervate brown fat via a descending projection to the raphe pallidus (RPa). These neurons also densely innervate ascending targets implicated in the central regulation of energy expenditure, including the hypothalamus and extended amygdala. Optogenetic stimulation of different projection targets reveals that DRNVgat neurons are capable of regulating thermogenesis through both a "direct" descending pathway through the RPa and multiple "indirect" ascending pathways. This work establishes a key regulatory role for DRNVgat neurons in controlling energy expenditure.

Prepuberal stress and obesity: effects onserum corticosterone, prolactin, testosterone andprecancerous prostate lesions in adult rats.

In the present study, we assessed the long-term effects of an acute pubertal stressor (immune-challenge) or obesity on the development of precancerous lesions in rats. Pubertal male rats received a single injection of lipopolysaccharide (LPS) or saline during puberty (5weeks of age). In adulthood (8weeks old), subgroups of males were fed with hypercaloric liquid diet to induce obesity. This resulted in a total of six subgroups: (1)intact-non obese, (2) intact-obese, (3) saline-non obese, (4) saline-obese, (5) LPS-non obese, and (6) LPS-obese. At 16weeks of age the rats were sacrified for prostate histology (hematoxylin and eosin stain) and hormone analysis (testosterone, corticosterone and prolactin). As compared to intact-non obese rats, males treated with LPS and those with obesity expressed histological alterations in both the dorsolateral and ventral portions of the prostate. Only prolactin was altered in LPS-treated males, whereas corticosterone was altered in LPS-obese rats. These results indicate that puberal exposure to an immune challenge or obesity facilitate the development of prostatic lesions in adult male rats. We discuss the role of hormones in the development of precancerous lesions.

Emotion and the Cardiovascular System: Postulated Role of Inputs From the Medial Prefrontal Cortex to the Dorsolateral Periaqueductal Gray.

The midbrain periaqueductal gray (PAG) plays a major role in generating different types of behavioral responses to emotional stressors. This review focuses on the role of the dorsolateral (dl) portion of the PAG, which on the basis of anatomical and functional studies, appears to have a unique and distinctive role in generating behavioral, cardiovascular and respiratory responses to real and perceived emotional stressors. In particular, the dlPAG, but not other parts of the PAG, receives direct inputs from the primary auditory cortex and from the secondary visual cortex. In addition, there are strong direct inputs to the dlPAG, but not other parts of the PAG, from regions within the medial prefrontal cortex that in primates correspond to cortical areas 10 m, 25 and 32. I first summarise the evidence that the inputs to the dlPAG arising from visual, auditory and olfactory signals trigger defensive behavioral responses supported by appropriate cardiovascular and respiratory effects, when such signals indicate the presence of a real external threat, such as the presence of a predator. I then consider the functional roles of the direct inputs from the medial prefrontal cortex, and propose the hypothesis that these inputs are activated by perceived threats, that are generated as a consequence of complex cognitive processes. I further propose that the inputs from areas 10 m, 25 and 32 are activated under different circumstances. The input from cortical area 10 m is of special interest, because this cortical area exists only in primates and is much larger in the brain of humans than in all other primates.

A Review of the Pedunculopontine Nucleus in Parkinson's Disease.

The pedunculopontine nucleus (PPN) is situated in the upper pons in the dorsolateral portion of the ponto-mesencephalic tegmentum. Its main mass is positioned at the trochlear nucleus level, and is part of the mesenphalic locomotor region (MLR) in the upper brainstem. The human PPN is divided into two subnuclei, the pars compacta (PPNc) and pars dissipatus (PPNd), and constitutes both cholinergic and non-cholinergic neurons with afferent and efferent projections to the cerebral cortex, thalamus, basal ganglia (BG), cerebellum, and spinal cord. The BG controls locomotion and posture via GABAergic output of the substantia nigra pars reticulate (SNr). In PD patients, GABAergic BG output levels are abnormally increased, and gait disturbances are produced via abnormal increases in SNr-induced inhibition of the MLR. Since the PPN is vastly connected with the BG and the brainstem, dysfunction within these systems lead to advanced symptomatic progression in Parkinson's disease (PD), including sleep and cognitive issues. To date, the best treatment is to perform deep brain stimulation (DBS) on PD patients as outcomes have shown positive effects in ameliorating the debilitating symptoms of this disease by treating pathological circuitries within the parkinsonian brain. It is therefore important to address the challenges and develop this procedure to improve the quality of life of PD patients.

Periaqueductal gray glutamatergic, cannabinoid and vanilloid receptor interplay in defensive behavior and aversive memory formation

Stimulation of the midbrain periaqueductal gray matter (PAG) in humans elicits sensations of fear and impending terror, and mediates predator defensive responses in rodents. In rats, pharmacological stimulation of the dorsolateral portion of the PAG (dlPAG) with N-Methyl-d-Aspartate (NMDA) induces aversive conditioning that acts as an unconditioned stimulus (US). In the present work, we investigated the interplay between the vanilloid TRPV1 and cannabinoid CB1 receptors in the NMDA-dlPAG defensive response and in subsequent aversive learning. Rats were subjected to dlPAG NMDA infusion in an olfactory conditioned stimulus (CS) task allowing the evaluation of immediate and long-term defensive behavioral responses during CS presentation. The results indicated that an intermediate dose of NMDA (50 pmol) induced both immediate and long-term effects. A sub-effective dose of NMDA (25 pmol) was potentiated by the TRPV1 receptor agonist capsaicin (CAP, 1 nmol) and the CB1 receptor antagonist, AM251 (200 pmol). CAP (10 nmol) or the combination of CAP (1 nmol) and AM251 (200 pmol) induced long-term effects without increasing immediate defensive responses. The glutamate release inhibitor riluzole (2 or 4 nmol) and the AMPA/kainate receptor antagonist DNQX (2 or 4 nmol) potentiated the immediate effects but blocked the long-term effects. The results showed that immediate defensive responses rely on NMDA receptors, and aversive learning on the fine-tuning of TRPV1, CB1, metabotropic glutamate and AMPA receptors located in pre- and postsynaptic membranes. In conclusion, the activity of the dlPAG determines core affective aspects of aversive memory formation controlled by local TRPV1/CB1 balance.

Bidirectional Control of Reversal in a Dual Action Task by Direct and Indirect Pathway Activation in the Dorsolateral Striatum in Mice.

The striatum is a key brain structure involved in the processing of cognitive flexibility, which results from the balance between the flexibility demanded for novel learning of motor actions and the inflexibility required to preserve previously learned actions. In particular, the dorsolateral portion of the striatum (DLS) is engaged in the learning of action sequence. This process is temporally driven by fine adjustments in the function of the two main neuronal populations of the striatum, known as the direct pathway medium spiny neurons (dMSNs) and indirect pathway medium spiny neurons (iMSNs). Here, using optogenetics, behavioral, and electrophysiological tools, we addressed the relative role of both neuronal populations in the acquisition of a reversal dual action sequence in the DLS. While the channelrhodopsin-induced activation of dMSNs and iMSNs of the DLS did not induce changes in the learning rate of the sequence, the specific activation of the dMSNs of the DLS facilitated the acquisition of a reversal dual action sequence; the activation of iMSNs induced a significant deficit in the acquisition of the same task. Taken together our results indicate an antagonistic relationship between dMSNs and iMSNs on the acquisition of a reversal dual action sequence.

Landmarks for the Location of the Subthalamic Nucleus Using Magnetic Resonance Imaging

AbstractDeep brain stimulation has become an option for advanced Parkinson's disease treatment since the 1990s, but the first reports are from Benabid's team, a French neurosurgeon, in the 1980s. The subthalamic nucleus (STN), more specifically its dorsolateral portion, is the most commonly stimulated brain area. One of the major aspects for a good surgical result is the accurate location of this target. Therefore, the present article aimed to identify landmarks that facilitate and refine the location of the STN using nuclear magnetic resonance imaging (NMRI) of the skull. In order to achieve this goal, a search for articles was performed using the PubMed and Science Direct online databases, and articles regarding the use of NMRI to target STN were included. The precise location of the dorsolateral portion of the STN is fundamental to achieve the best possible effect on motor symptoms and to minimize side effects. One of the most used location methods is the NMRI, associated or not with tomography or ventriculography. The location strategies can be classified as direct and indirect. Landmarks are among the indirect strategies, and the most important ones (red nucleus, Sukeroku sign, dent internal capsule sign, supramammillary commissure, mammillothalamic tract, and interpeduncular cistern) are described in the present article. The various landmarks can be combined to locate with more accuracy the dorsolateral portion of the STN and the ideal position of the electrodes to achieve the best possible clinical result.

Neuroimaging Findings Related to Behavioral Disturbances in Alzheimer&#39;s Disease: A Systematic Review.

Behavioral and psychological symptoms of dementia (BPSD) associated with Alzheimer's Disease (AD) have been linked to structural and functional alterations in fronto-temporal circuits and cortical abnormalities. However, little is known on how specific volumetric and functional brain changes may be associated with the frequency, severity and pattern of BPSD. A systematic review of the literature regarding neuroimaging and BPSD changes in AD was performed through Pubmed/Medline, ISI, and EMBASE electronic databases from January 2000 to May 2015. Eligible references (n=40) included clinical studies in which structural or functional neuroimaging assessment was performed in AD subjects presenting BPSD features. BPSD symptoms, particularly apathy and psychosis have been associated in most of studies with either volume reductions or decreased metabolism in the prefrontal cortex (orbital and dorsolateral portions), anterior cingulate, insula and temporal lobes (middle portion). WM lacunes associated with AD progression have been associated with depressive symptoms. The sum of evidence highlights the importance of BPSD-related imaging findings for the understanding of the non-cognitive symptom spectrum in AD. Results suggest that structural and functional changes in fronto-limbic areas may lead to emotional deregulation and symptom unawareness. As these findings may be present early on the AD clinical course, they may have a relevance for the development of imaging markers that could be used in diagnosis, disease monitoring and prediction of therapeutic response.

EFFECT OF COPULATION ON POTENTIALLY PRECANCEROUS PROSTATE LESIONS, SERUM TESTOSTERONE AND PROLACTIN LEVELS IN RATS

The prostate is an exocrine reproductive gland that participates in ejaculation and it is prone to diseases, including cancer. In thepre-sent study, we assessed the long-term effects of copulation on the development of precancerous lesions in rats, and compared them with testosterone-induced prostatic lesions. One group of Wistar males was given 10 copulatory sessions to one ejaculation with ovariectomized, hormone-primed females. Sessions occurred twice per week for a total of ten trials. Asecond group was exposed to females during the same trials, but physical contact was prevented. In addition, each group received a subcutaneous implant in the back either filled with testosterone propionate (T, 100 mg/kg) or empty. This resulted in four subgroups: 1)Control + No sex, 2) Control + Sex, 3) T + No sex and 4) T + Sex. Two days after the 10(th) trial all the males were sacrificed for prostate histo-logy (H&E) and hormone analysis (testosterone and prolactin). Males from the group Control + No sex expressed normal histo-logy. However, those in the groups Control + Sex and T + No sex expressed metaplasia and dysplasia in both the dorsolateral and ventral portions of the prostate, respectively. Interestingly, males from the group T + Sex expressed dysplasia in the dorsolateral prostate only, but not in the ventral prostate. These results indicate that constant copulation may facilitate the development of prostatic lesions in males with normal levels of testosterone. However, copulation induces less lesions in the ventral prostate of males treated with testosterone.

Nuclear organization of the substantia nigra, ventral tegmental area and retrorubral field of the common marmoset (Callithrix jacchus): A cytoarchitectonic and TH-immunohistochemistry study

It is widely known that the catecholamine group is formed by dopamine, noradrenaline and adrenaline. Its synthesis is regulated by the enzyme called tyrosine hydroxylase. 3-hydroxytyramine/dopamine (DA) is a precursor of noradrenaline and adrenaline synthesis and acts as a neurotransmitter in the central nervous system. The three main nuclei, being the retrorubral field (A8 group), the substantia nigra pars compacta (A9 group) and the ventral tegmental area (A10 group), are arranged in the die-mesencephalic portion and are involved in three complex circuitries – the mesostriatal, mesolimbic and mesocortical pathways. These pathways are involved in behavioral manifestations, motricity, learning, reward and also in pathological conditions such as Parkinson’s disease and schizophrenia. The aim of this study was to perform a morphological analysis of the A8, A9 and A10 groups in the common marmoset (Callithrix jacchus – a neotropical primate), whose morphological and functional characteristics support its suitability for use in biomedical research. Coronal sections of the marmoset brain were submitted to Nissl staining and TH-immunohistochemistry. The morphology of the neurons made it possible to subdivide the A10 group into seven distinct regions: interfascicular nucleus, raphe rostral linear nucleus and raphe caudal linear nucleus in the middle line; paranigral and parainterfascicular nucleus in the middle zone; the rostral portion of the ventral tegmental area nucleus and parabrachial pigmented nucleus located in the dorsolateral portion of the mesencephalic tegmentum. The A9 group was divided into four regions: substantia nigra compacta dorsal and ventral tiers; substantia nigra compacta lateral and medial clusters. No subdivisions were made for the A8 group. These results reveal that A8, A9 and A10 are phylogenetically stable across species. As such, further studies concerning such divisions are necessary in order to evaluate the occurrence of subdivisions that express DA in other primate species, with the aim of characterizing its functional relevance.

Origins of multisynaptic projections from the basal ganglia to the forelimb region of the ventral premotor cortex in macaque monkeys.

The ventral premotor cortex (PMv), occupying the ventral aspect of area 6 in the frontal lobe, has been implicated in action planning and execution based on visual signals. Although the PMv has been characterized by cortico-cortical connections with specific subregions of the parietal and prefrontal cortical areas, a topographical input/output organization between the PMv and the basal ganglia (BG) still remains elusive. In the present study, retrograde transneuronal labelling with the rabies virus was employed to identify the origins of multisynaptic projections from the BG to the PMv. The virus was injected into the forelimb region of the PMv, identified in the ventral aspect of the genu of the arcuate sulcus, in macaque monkeys. The survival time after the virus injection was set to allow either the second- or third-order neuron labelling across two or three synapses. The second-order neurons were observed in the ventral portion (primary motor territory) and the caudodorsal portion (higher-order motor territory) of the internal segment of the globus pallidus. Subsequently, the third-order neurons were distributed in the putamen caudal to the anterior commissure, including both the primary and the higher-order motor territories, and in the ventral striatum (limbic territory). In addition, they were found in the dorsolateral portion (motor territory) and ventromedial portion (limbic territory) of the subthalamic nucleus, and in the external segment of the globus pallidus including both the limbic and motor territories. These findings indicate that the PMv receives diverse signals from the primary motor, higher-order motor and limbic territories of the BG.

Cholinergic, but not NMDA, receptors in the lateral entorhinal cortex mediate acquisition in trace eyeblink conditioning.

Anatomical and electrophysiological studies collectively suggest that the entorhinal cortex consists of several subregions, each of which is involved in the processing of different types of information. Consistent with this idea, we previously reported that the dorsolateral portion of the entorhinal cortex (DLE), but not the caudomedial portion, is necessary for the expression of a memory association between temporally discontiguous stimuli in trace eyeblink conditioning (Morrissey et al. (2012) J Neurosci 32:5356-5361). The present study examined whether memory acquisition depends on the DLE and what types of local neurotransmitter mechanisms are involved in memory acquisition and expression. Male Long-Evans rats experienced trace eyeblink conditioning, in which an auditory conditioned stimulus (CS) was paired with a mildly aversive electric shock to the eyelid (US) with a stimulus-free interval of 500 ms. Immediately before the conditioning, the rats received a microinfusion of neuroreactive substances into the DLE. We found that reversible inactivation of the DLE with GABAA receptor agonist, muscimol impaired memory acquisition. Furthermore, blockade of local muscarinic acetylcholine receptors (mACh) with scopolamine retarded memory acquisition while blockade of local NMDA receptors with APV had no effect. Memory expression was not impaired by either type of receptor blocker. These results suggest that the DLE is necessary for memory acquisition, and that acquisition depends on the integrity of local mACh receptor-dependent firing modulation, but not NMDA receptor-dependent synaptic plasticity.