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PubMed1997

Hitchcock's "Vertigo": the collapse of a rescue fantasy.

The author presents an interpretation of Hitchcock's 'Vertigo', focusing on the way in which its protagonist's drama resonates with the analyst's struggle with deep unconscious identifications, with the impossibility of maintaining detached objectivity or guaranteeing one's role as a reparative good object and with the dangers of grandiosity, omniscience and illusory control. The protagonist's 'countertransference love' crystallises around a rescue fantasy in which he is Orpheus striving to bring Eurydice back from Hades, or a Knight determined to behead an obscure Dragon endangering Beauty. Initially these key roles are sharply differentiated, through splitting and disavowal, which deprive the participants of their conflictual three-dimensionality. Eventually, however, the valiant Knight turns out to be as helpless and lonely as his Beauty, and in the final scene as ruthless and lethal as the Dragon. This interpretation is compared to numerous other views of the film offered in the literature. The survey and comparison of the various views leads to fundamental issues in the psychoanalytic study of art. Interpretations can be seen as unavoidably coloured by the (counter)transference of viewers. It is suggested that a film has no hidden true meaning, and a new individual significance emerges in the transitional space opened up by each viewer's encounter with the emotional universe of the film. A defensive emphasis on the pathology of artists and their work may alienate us from art, and blind us to ways in which we could learn from it personally and professionally.

Drama↗

PubMed2025

Uncovering the genetic architecture of ME/CFS: a precision approach reveals impact of rare monogenic variation.

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disabling and heterogeneous disorder lacking validated biomarkers or targeted therapies. Clinical variability and elusive pathophysiology hinder progress toward effective diagnostics and treatment. Core symptoms include persistent fatigue, post-exertional malaise, unrefreshing sleep, cognitive dysfunction, and pain. We tested whether an individualized, “n-of-1” genomic and transcriptomic framework combined with comprehensive, participant-informed phenotyping could reveal molecular signatures unique to each patient. METHODS: Clinical-grade whole-genome sequencing was conducted in 31 affected individuals from 25 families, with RNA-seq performed on a subset (16 affected, 7 unaffected) using blood samples. Machine-learning assisted variant triage, transcript-aware damage prediction, and expert review identified pathogenic or likely pathogenic variants in 8 of 25 probands (32%) and 12 of 31 affected individuals (39%). RESULTS: Findings revealed marked genetic heterogeneity, including large-effect rare and more common variants. Implicated pathways included ATP generation, oxidative phosphorylation, fatty acid oxidation; regulation of glycolysis, amino acid and lipid turnover; ion and solute homeostasis; synaptic signaling, excitability, oxygen transport, and muscle integrity, resilience, and post-exertional recovery; previously implicated processes. Plausible modifiers influencing disease onset, severity, and relapsing–remitting patterns and possibly explaining intrafamilial variability and inconsistent findings across studies, were also identified. Despite gene-level diversity, downstream effects converged on impaired energy production, reduced stress resilience, and vulnerability to post-exertional metabolic failure; disruptions consistent with core ME/CFS symptoms of exertional intolerance, cognitive fog, and fatigue. CONCLUSIONS: Our findings support the hypothesis that at least a subset of ME/CFS cases represent distinct molecular disorders that converge on shared physiological pathways. Validation in larger, more diverse cohorts will be essential to test this hypothesis and establish generalizability, but increase size alone is unlikely to resolve causation in a disorder defined by rarity, heterogeneity, and molecular complexity. We suggest that progress will require experimental designs that integrate individual-level genomic data with deep, participant-informed deep phenotyping, capturing the combined effects of rare and common variants and environmental modifiers on disease expression and progression. We believe that an individualized precision medicine framework will uncover molecular drivers and modifiers of ME/CFS previously obscured by heterogeneity, enabling biologically informed stratification, improved trial design, biomarker discovery, and targeted interventions in this historically neglected condition.

Humans↗

PubMed1990

Deep dysphasia: analysis of a rare form of repetition disorder.

"Deep dysphasia" is the parallel in repetition to the reading impairment deep dyslexia. Our patient, S.M., showed part of speech, word/nonword, and concreteness effects in repetition, and he made semantic errors, but his oral reading was relatively spared. Further testing indicated that S.M. did not have difficulty perceiving spoken stimuli or deciding their lexical status, but he was deficient at semantically processing spoken words. Moreover, his phonemic memory was severely impaired. We argue that the routes for repetition (lexical and nonlexical) that function without semantic mediation were defective and that deficits in phonemic memory further diminished their effectiveness, since initial phonological encoding of spoken words was not available to guide the output stages of phonological processing. In addition, the semantically mediated route for repetition was unreliable because semantic processing was faulty and S.M. could not accurately label concepts.

Aged↗

PubMed2004

Topographic distribution of direct and hippocampus- mediated entorhinal cortex activity evoked by olfactory tract stimulation.

Olfactory information is central for memory-related functions, such as recognition and spatial orientation. To understand the role of olfaction in learning and memory, the distribution and propagation of olfactory tract-driven activity in the parahippocampal region needs to be characterized. We recently demonstrated that repetitive stimulation of the olfactory tract in the isolated guinea pig brain preparation induces an early direct activation of the rostrolateral entorhinal region followed by a delayed response in the medial entorhinal cortex (EC), preceded by the interposed activation of the hippocampus. In the present study we performed a detailed topographic analysis of both the early and the delayed entorhinal responses induced by patterned stimulation of the lateral olfactory tract in the isolated guinea pig brain. Bi-dimensional maps of EC activity recorded at 128 recording sites with 4 x 4 matrix electrodes (410 microm interlead separation) sequentially placed in eight different positions, showed (i) an early (onset at 16.09 +/- 1.2 ms) low amplitude potential mediated by the monosynaptic LOT input, followed by (ii) an associative potential in the rostral EC which originates from the piriform cortex (onset at 33.2 +/- 2.3 ms), and (iii) a delayed potential dependent on the previous activation of the hippocampus. The sharp component of the delayed response had an onset latency between 52 and 63 ms and was followed by a slow wave. Laminar profile analysis demonstrated that in the caudomedial EC the delayed response was associated with two distinct current sinks located in deep and in superficial layers, whereas in the rostrolateral EC a small-amplitude sink could be detected in the superficial layers exclusively. The present report demonstrates that the output generated by the hippocampal activation is unevenly distributed across different EC subregions and indicates that exclusively the medial and caudal divisions receive a deep-layer input from the hippocampus. In the rostrolateral EC, specific network interactions may be generated by the convergence of the direct olfactory input and the olfaction-driven hippocampal output.

Animals↗

PubMed2006

Recurrence after totally extraperitoneal laparoscopic repair: implications for operative technique and surgical training.

BACKGROUND: The totally extraperitoneal (TEP) approach is increasingly favoured for inguinal hernia repair. The learning curve is slow with high, early recurrence rates but the exact cause of recurrence is unknown. OBJECTIVE: To determine the reasons for recurrence, identify the critical operative steps and examine the influence of surgical experience and training on results. PATIENTS AND METHODS: All patients undergoing TEP between 1993 and 2004 were included. Patients requiring re-operation for recurrence were identified and examined in detail. RESULTS: Eight surgical teams performed 1682 TEP repairs. Fifty five hernias recurred (3.27%) with a median follow-up of seven years (range 1-11 years). In six recurrences, the first repair was itself for recurrence and in 24, the initial repair was bilateral. The initial hernia was direct in 26 and indirect in 29 patients. These distributions were similar to a control sample. At re-operation, indirect recurrence was more common with 18 direct, and 37 indirect cases (P=0.020). At re-operation, when the original mesh could be identified (18 repairs), it appeared to have moved superiorly in 13 cases. Typically, recurrence occurred in 10% of a surgeon's first 20 cases, 4% of the next 60 cases and falling to below 2% thereafter. CONCLUSION: TEP repairs have a tendency for indirect recurrence even after direct repair. Meshes tend to migrate superiorly. Results suggest that recurrence occurs most often because of failure to fully expose the deep inguinal ring and/or to adequately spread the mesh inferiorly and laterally. We recommend particular attention be paid to these technical aspects. Acceptable results are obtainable after an experience of 20 cases but further improvement in results occurs as experience reaches 80 operations. With a large number of consultants having little or no experience in TEP surgery, there is an urgent need for 'hands-on' training courses so that all patients have access to TEP, particularly those with bilateral or recurrent inguinal herniae.

Adult↗

PubMedDate not supplied

Firing characteristics of deep layer neurons in prefrontal cortex in rats performing spatial working memory tasks.

Single cells were recorded with 'tetrodes' in regions of the rat medial prefrontal cortex, including those which are targets of hippocampal afferents, while rats were performing three different behavioral tasks: (i) an eight-arm radial maze, spatial working memory task, (ii) a figure-eight track, delayed spatial alternation task, and (iii) a random food search task in a square chamber. Among 187 recorded units, very few exhibited any evidence of place-specific firing on any of the behavioral tasks, except to the extent that different spatial locations were related to distinct phases of the task. Furthermore, no prefrontal unit showed unambiguous spatially dependent delay activity that might mediate working memory for spatial locations. Rather, the cells exhibited diverse correlates that were generally associated with the behavioral requirements of performing the task. This included firing related to intertrial intervals, onset or end of trials, selection of specific arms on the eight-arm radial maze, delay periods, approach to or departure from goals, and selection of paths on the figure-eight track. Although a small number of cells showed similar behavioral correlates across tasks, the majority of cells showed no consistent correlate when recorded across multiple tasks. Furthermore, some units did not exhibit altered firing patterns in any of the three tasks, while others showed changes in firing that were not consistently related to specific behaviors or task components. These results are in agreement with previous lesion and behavioral studies in rats that suggest a prefrontal cortical role in encoding 'rules' (i.e. structural features) or behavioral sequences within a task but not in encoding allocentric spatial information. Given that the hippocampal projection to this cortical region is capable of undergoing LTP, our data lead to the hypothesis that the role of this projection is not to impose spatial representations upon prefrontal activity, but to provide a mechanism for learning the spatial context in which particular behaviors are appropriate.

Action Potentials↗

PubMed1997

Collective memory: collaborative and individual processes in remembering.

Two experiments compared collaborative and individual recall. In Experiment 1, participants encoded pictures and words with a deep or shallow processing task, then recalled them twice either individually or collaboratively. Collaborative groups recalled more than individuals, but less than nominal groups (pooled individuals), thus exhibiting collaborative inhibition. However, group recall appeared to be more stable over time than individual recall. Groups and individuals both showed a picture-superiority effect, a level-of-processing effect, and hypermnesia. In Experiment 2, participants recalled the story "War of the Ghosts" (from F. C. Bartlett, 1932), and again collaborative groups recalled more than individuals, but less than nominal groups. Both the individual and collaborative recalls were highly organized. There was evidence that the collaborative groups tended to rely on the best individual to a greater extent in story than in list recall. Possible social and cognitive mechanisms are considered.

Adolescent↗

PubMed2000

The effect of encoding manipulations on neural correlates of episodic retrieval.

The present experiments investigated whether the neural correlates of explicit (conscious) retrieval from episodic memory vary qualitatively according to conditions at encoding, as is predicted by current views of the neural basis of memory retrieval. Event-related potential (ERP) correlates of word stem (e.g. MOT_) cued recall were compared for items studied under different encoding conditions. In Experiment 1, encoding was either 'shallow' or 'deep' whereas in Experiment 2 the presentation modality of the study items was either visual or auditory. In both experiments robust ERP memory effects were observed for stems completed with explicitly retrieved items from each encoding condition. The effects varied in their magnitude, such that they were largest when elicited by the more memorable class of item in each experiment. The scalp distributions of the effects did not differ according to encoding condition, a finding which offers no support for the view that retrieval involves the literal reinstatement of neural activity engaged at the time of encoding. The findings instead point to the existence of a set of retrieval operations that are engaged regardless of the conditions under which retrieved information is encoded.

Adolescent↗

PubMed2000

Differential effects of deep cerebellar nuclei inactivation on reaching and adaptive control.

This study examined the effects of selective inactivation of the cerebellar nuclei in the cat on the control of multijoint trajectories and trajectory adaptation to avoid obstacles. Animals were restrained in a hammock and trained to perform a prehension task in which they reached to grasp a small cube of meat from a narrow food well. To examine trajectory adaptation, reaching was obstructed by placing a horizontal bar in the limb's path. Inactivation was produced by microinjection of the GABA agonist muscimol (0.25-1.0 microg in 1 microL saline). Fastigial nucleus inactivation produced a severe impairment in balance and in head and trunk control but no effect on reaching and grasping. Dentate inactivation slowed movements significantly and produced a significant increase in tip path curvature but did not impair reaching and grasping. Selective inactivation of the anterior and posterior interpositus nuclei did not impair grasping but severely decreased the accuracy of reaching movements and produced different biases in wrist and paw paths. Anterior interpositus inactivation produced movement slowing (wrist speed) and under-reaching to the food well. Wrist and tip paths showed anterior biases and became more curved. Also animals could no longer make anticipatory adjustments in limb kinematics to avoid obstructions but sensory-evoked corrective responses were preserved. Posterior interpositus inactivation produced a significant increase in wrist speed and overreaching. Wrist and tip paths showed a posterior bias and became more curved, although in a different way than during anterior interpositus inactivation. Posterior interpositus inactivation did not impair trajectory adaptation to reach over the obstacle. During inactivation of either interpositus nucleus, all measures of kinematic temporal and spatial variability increased with somewhat greater effects being produced by anterior interpositus inactivation. We discuss our results in relation to the hypothesis that anterior and posterior interpositus have different roles in trajectory control, related possibly to feed-forward use of cutaneous and proprioceptive inputs, respectively. The loss of adaptive reprogramming during anterior interpositus inactivation further suggests a role in motor learning. Comparison with results from our earlier motor cortical study shows that the distinctive impairments produced by inactivation of these two nuclei are similar to those produced by selective inactivation of different zones in the forelimb area of rostral motor cortex. Our findings are consistent with the hypothesis that there are separate functional output channels from the anterior and posterior interpositus nuclei to rostral motor cortex for distinct aspects of trajectory control and, from anterior interpositus alone, for trajectory adaptation.

Adaptation, Physiological↗

PubMed2004

Prospective randomized controlled trial: conventional versus powered phlebectomy.

OBJECTIVES: Transilluminated powered phlebectomy (TriVex) is a new surgical technique that uses tumescent dissection, transillumination, and powered phlebectomy. The purpose of this study was to compare TriVex with conventional varicose vein surgery in terms of pain, cosmesis, recurrence, complications, and operating time. METHODS: One hundred eighty-eight limbs in 141 patients (33 men, 108 women; mean age, 42.5 years) with varicose veins were randomised to conventional (n = 100) or TriVex (n = 88). Exclusion criteria were venous ulceration or deep venous disease. Varicosities were graded with CEAP and clinical assessment (grades 1-3), and were similar in both groups. Randomization was single blinded. Long or short saphenous vein ligation or stripping was performed as indicated with duplex scanning. Operative time was from skin incision to leg bandaging. Phlebectomy was performed with conventional stab avulsions or TriVex. Patients completed assessment forms preoperatively and postoperatively (2, 6, 26, 52 weeks), and this was supplemented with physician clinical evaluation. Pain was assessed with visual analog score. RESULTS: There was a significant difference in the number of incisions for phlebectomy in the two groups (conventional, n = 29; TriVex, n = 5; P <.0001). TriVex was faster in the grade 3 (extensive) group, but this did not reach statistical significance. There was no difference in mean postoperative pain score over 8 days in the two groups (P =.4624). At 2 weeks there was no significant difference between the groups with regard to bruising (P =.77), cellulitis (P =.33), and numbness (P =.33). At 6 weeks there was no significant difference between the groups with regard to nerve injury (P =.97), residual veins (P =.79), cosmetic score (P =.837), and overall satisfaction (P =.878). At 6 and 12 months, there was no significant difference in cosmesis (P =.955, P =.088, respectively) or recurrence (P =.27, P =.11, respectively). CONCLUSIONS: TriVex is a safe and effective method for excision of varicosities and compares well, after a learning curve, with conventional surgery in regard to complications and recurrence. It has the advantage of a trend toward reduced operating time in extensive varicosities, and significantly fewer incisions, although there was no perceived difference in cosmesis during follow-up.

Adult↗

PubMed2000

When does a deep dyslexic make a semantic error? The roles of age-of-acquisition, concreteness, and frequency.

Semantic reading errors are the central and defining feature of deep dyslexia. This study compared the words the deep dyslexic patient LW read correctly with those she omitted and those to which she produced semantic errors in terms of their concreteness, age-of-acquisition, frequency, and length. Semantic errors were made to less concrete, later-acquired, and shorter words than were read correctly; there was no reliable effect of word frequency. More importantly, the actual semantic errors produced were later-acquired than the stimulus words, but they were not more concrete or reliably more frequent. These results implicate age-of-acquisition in the process that produces semantic errors. It is proposed that concreteness determines the specificity of the semantic system to activate a set of candidate responses and that age-of-acquisition biases the ease with which certain words can be selected from this set to be produced as reading responses.

Age Factors↗

PubMed1994

Rates and patterns of chloroplast DNA evolution.

The chloroplast genome (cpDNA) of plants has been a focus of research in plant molecular evolution and systematics. Several features of this genome have facilitated molecular evolutionary analyses. First, the genome is small and constitutes an abundant component of cellular DNA. Second, the chloroplast genome has been extensively characterized at the molecular level providing the basic information to support comparative evolutionary research. And third, rates of nucleotide substitution are relatively slow and therefore provide the appropriate window of resolution to study plant phylogeny at deep levels of evolution. Despite a conservative rate of evolution and a relatively stable gene content, comparative molecular analyses reveal complex patterns of mutational changes. Non-coding regions of cpDNA diverge through insertion/deletion changes that are sometimes site dependent. Coding genes exhibit different patterns of codon bias that appear to violate the equilibrium assumptions of some evolutionary models. Rates of molecular change often vary among plant families and orders in a manner that violates the assumption of a simple molecular clock. Finally, protein-coding genes exhibit patterns of amino acid change that appear to depend on protein structure, and these patterns may reveal subtle aspects of structure/function relationships. Only comparative studies of molecular sequences have the resolution to reveal this underlying complexity. A complete description of the complexity of molecular change is essential to a full understanding of the mechanisms of evolutionary change and in the formulation of realistic models of mutational processes.

Biological Evolution↗

PubMed1987

Physical fitness for the mature woman.

The ability to perform physical activity, whether at work or as recreation, is an important aspect of human experience for men and women of all ages. The extension of the range of physical power output that characterizes improvement in "physical fitness" is a desirable goal for all. It helps to make physical activity more enjoyable and less fatiguing, it can facilitate the learning of new skills and may actually improve cognitive functions, and it decreases the likelihood of physical injury and helps to speed recovery from injury. A sound mind in a sound body has been a medical ideal since Greek and Roman times. For a continuing state of good health, all systems--physical, mental, and spiritual--should be exercised in harmony. At the beginning of the twentieth century, the average life span for women was barely 5 years beyond the menopause. Menopause heralded the twilight years of life and enhanced susceptibility to disease and deterioration of health. Today, women look forward to 25 additional years, a full one third of a lifetime; menopause now heralds potential promise, adventure, and exploration, an exciting new phase of the life cycle. Exercise represents a vital part of a prescription to maximize quality of life throughout this period. Physical conditioning cannot be expected to complete reverse the unrelenting effects of passing time, but it appears that it can substantially modify this process. Functional losses that in the past have been attributed only to age may, in fact, represent a combined effect of biologic aging and physical inactivity. Exercise helps to maintain the physiologic adaptations that support an enhanced biologic reserve in body systems that tend to lose reserve capacity with advancing age. "If you don't use it, you lose it!," and its positive corollary, "If you use it, you enthuse it!," may be maxims that imply a natural law of deep consequence. An optimal diet and suitably vigorous activity are advisable for all women as they enter the postmenopausal phase of life. Every mature woman ought to carefully consider choosing to pursue an appropriate goal: active participation in a specific exercise program under medical supervision. The health care system should be fully responsive to the special needs of the mature woman, and the importance of providing programs of physical activity designed to address these needs should be recognized. For the postmenopausal woman, the advantages of achieving a state of physical fitness are many.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗

PubMed2005

Cerebellar inhibition of inferior olivary transmission in the decerebrate ferret.

Stimulation around the superior cerebellar peduncle or within the deep cerebellar nuclei is known to inhibit the inferior olive with a very long latency. It has been suggested that this inhibition is mediated by the GABA-ergic nucleo-olivary pathway, but alternative explanations such as activation of an indirect excitatory pathway or a pathway via the red nucleus are possible. A long-latency inhibition via the nucleo-olivary pathway would have profound implications for cerebellar function and the present study was performed to test alternative explanations and to characterize the nucleo-olivary inhibition. Climbing fibre responses (CFRs), evoked by periorbital stimulation and recorded from the cerebellar cortex, could be inhibited by stimulation of two distinct mesencephalic areas. One was located within the superior cerebellar peduncle and the other about 1 mm further ventrally. Inhibition evoked from either area occurred in the inferior olive and was independent of a red nucleus relay. Single Purkinje cell recordings revealed that inhibition from the ventral area was not secondary to olivary activation. It is concluded that stimulation of the ventral area activated nucleo-olivary fibres. The inhibition elicited by stimulation within the peduncle probably resulted from indirect activation on the nucleo-olivary fibres via antidromic activation of the interpositus nucleus. The time courses of the inhibition from the two areas were indistinguishable. The duration of the strongest inhibition was short and had a sharp peak at about 30 ms. It is suggested that the time course of the inhibition is important for temporal regulation of learned responses.

Animals↗

PubMed1988

Neuropharmacological correlates of the motor syndrome of the genetically dystonic (dt) rat.

The research program described here has focused primarily on identifying sites of dysfunction in the central nervous system of rat mutants described as dystonic. The evidence strongly favors the position that there is a defect in the cerebellum of the dt rat. At present it seems reasonable to propose as a working hypothesis that there is a defect in the Purkinje cells that renders these neurons less sensitive to the excitatory neurotransmitters released by the climbing and parallel fibers. The finding that an abnormality in GAD activity in the deep cerebellar nuclei is relatively localized when first detected but spreads over time as the motor syndrome intensifies may indicate that there is a progressive decline in the function of the Purkinje cells. The fact that electrophysiological techniques detect a mixture of relatively normal and abnormal Purkinje cell activity in animals with advanced symptoms is consistent with such a proposal. Finding significant abnormalities in the cerebellum of the dt rat does not necessarily mean that this is the site of the primary defect responsible for the motor syndrome seen in these animals. We have failed to detect any signs of dysfunction in the basal ganglia, the presumed locus of a defect in human torsion dystonia. However, our investigations have been limited almost exclusively to the striatum. Thus, the possibility of defects at other sites, such as the globus pallidus or thalamus must be considered. Although we have not yet demonstrated that the abnormalities detected in the cerebellum are causally related to the behavior of the dt rat, the behavioral syndrome is consistent with a cerebellar defect. It has been suggested that the cerebellum is important for the continuing calibration of coordinated motor behavior. Important observations on the effects of cerebellar lesions have come from the study of the oculomotor system. Lesions in the cerebellum have been shown to eliminate the ability to recalibrate the saccadic eye movement system and to destroy the adaptive plasticity of the vestibulo-ocular reflex A cerebellar defect could result in a failure in motor learning or in the calibration of motor systems that must take place as the rat pup masters adult patterns of locomotion. We note that lesions of the climbing fiber system with 3-AP lead to some of the same biochemical effects seen in dt rats but do not produce an identical behavioral syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

Acetylcholine↗

PubMed2006

The effects of a subpsychotic dose of ketamine on recognition and source memory for agency: implications for pharmacological modelling of core symptoms of schizophrenia.

Ketamine is increasingly used to model the cognitive deficits and symptoms of schizophrenia. We investigated the extent to which ketamine administration in healthy volunteers reproduces the deficits in episodic recognition memory and agency source monitoring reported in schizophrenia. Intravenous infusions of placebo or 100 ng/ml ketamine were administered to 12 healthy volunteers in a double-blind, placebo-controlled, randomized, within-subjects study. In response to presented words, the subject or experimenter performed a deep or shallow encoding task, providing a 2(drug) x 2(depth of processing) x 2(agency) factorial design. At test, subjects discriminated old/new words, and recalled the sources (task and agent). Data were analyzed using multinomial modelling to identify item recognition, source memory for agency and task, and guessing biases. Under ketamine, item recognition and cued recall of deeply encoded items were impaired, replicating previous findings. In contrast to schizophrenia, there was a reduced tendency to externalize agency source guessing biases under ketamine. While the recognition memory deficit observed with ketamine is consistent with previous work and with schizophrenia, the changes in source memory differ from those reported in schizophrenic patients. This difference may account for the pattern of psychopathology induced by ketamine.

Adolescent↗

PubMed1995

Bioelectric and microcirculation cutaneous sensors for the study of vigilance and emotional response during tasks and tests.

Bioelectronic phenomena related to the activity of the Autonomic Nervous System (ANS) activity mainly take place in the deep part of the brain where they are difficult to record. The hand skin, being richly innervated by sympathetic efferent fibres, offers an interface from which relevant ANS-related signals can be recorded. Two non-invasive bioelectronic measurements (skin resistance and potential) reflecting the activity of the ANS were performed at the skin surface. These measurements were complemented by thermovascular (skin microcirculation and skin temperature) and cardiorespiratory (instantaneous heart rate and instantaneous respiratory frequency) measurements. The bioelectric measurements were performed using noninvasive Ag/AgCl electrodes. Non-metallic NASICON (Na Super Ionic Conductor) electrodes were tested and compared with traditional electrodes for the optimization of bioelectric measurements. Signal analysis and data processing was accomplished by means of original indices on a specially designed PC-based software. The methodology was used to evaluate vigilance level, mental workload, and emotional response during tasks (sporting activity, mental calculation, olfactive stimuli) and in critical situations (car crash avoidance).

Accidents, Traffic↗

PubMed2026

A systematic review of macaque brain stimulation: Trends and future directions.

Neurostimulation techniques can powerfully modulate neural circuit activity and provide causal insights into the relationship between brain function and behavior. Macaque monkeys have long been a key animal model for brain stimulation studies. While stimulating the macaque brain with one or a few electrodes has already taught us much about brain function and dysfunction, recent technological advances promise a future with more precise stimulation using many more electrodes. However, such possibilities also increase the number of choices an experimenter has when designing their study. We can learn from a rich past, but a comprehensive overview of which brain regions have been studied and with what stimulation parameters is lacking. Here, we present a PRISMA-compliant systematic review of 734 macaque brain stimulation studies using electrical and/or optogenetic stimulation. We find a striking bias in which brain areas have traditionally been stimulated: a mere 10 brain regions account for half of all studies, with the remainder of studies investigating approximately 150 other areas. Across studies, stimulation frequency robustly predicted direct behavioral effects independent of brain region, while amplitude did not. Future studies could more systematically explore less studied regions through lower stimulation frequencies (e.g., 20-50 Hz) alongside established ranges (∼200 Hz). Tools such as fMRI or optical imaging can capture neural circuit engagement evoked by these frequencies, even when behavioral effects are absent or remain subtle. Our synthesis offers a guide towards the next steps in high-channel-count, high-precision stimulation approaches.

Animals↗