Paired Sessions Research Articles

Simultaneous and cumulative effects of tDCS on cerebral metabolic rate of oxygen in multiple sclerosis.

Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique with simultaneous (during stimulation) and cumulative effects (after repeated sessions) on blood flow and neuronal metabolism. These effects remain mostly unclear especially in multiple sclerosis (MS). This work aims to elucidate brain metabolic and hemodynamic underpinnings of tDCS and its potential therapeutic impact in MS patients using quantitative tDCS-MRI. MS participants (n = 20; age = 45.4 ± 12.3 years, 7 males) underwent 3 T MRI scans before and after 20 daily sessions of dorsolateral prefrontal cortex (DLFPC) tDCS (2.0 mA, left anodal) paired with adaptive cognitive training (aCT). During both visits, imaging measurements of cerebral blood flow (CBF), cerebral venous blood oxygenation (Yv) and calculated cerebral metabolic rate of oxygen (CMRO2) were obtained at pre-tDCS, during-tDCS and post-tDCS. At baseline, significant increase from pre- to during-tDCS was observed in CMRO2 (7.6%; p = 0.002), CBF (11.0%; p < 0.0001) and Yv (1.9%; p = 0.006). At follow up, we observed an increase in pre-tDCS CMRO2 (140.59 ± 13.83 μmol/100 g/min) compared to baseline pre-tDCS levels (128.30 ± 14.00 μmol/100 g/min; p = 0.006). Sustained elevations in CMRO2 and CBF into post-tDCS were also observed (tDCS lingering effects). Cumulative tDCS effects were observed in the form of sustained elevations in CMRO2 and CBF in pre-tDCS follow up, reaching the magnitudes measured at baseline during-tDCS. TDCS induces an acute surge in metabolic activity persisting immediately after the stimulation is removed. Moreover, treatment composed of repeated tDCS-aCT paired sessions contributes to establishing long-lasting increases in neuronal activity.

Observational Study of Glycemic Impact of Anticipatory and Early-Race Athletic Competition Stress in Type 1 Diabetes.

Athletic competitions and the associated psychological stress are a challenge for people with type 1 diabetes (T1D). This study aims to understand the influence of anticipatory and early race competition stress on blood glucose concentrations and to identify personality, demographic, or behavioral traits indicative in the scope of the impact. Ten recreational athletes with T1D competed in an athletic competition and an exercise-intensity matched non-competition "training" session for comparison. The two hours prior to exercise and the first 30 minutes of exercise were compared between the paired exercise sessions to assess the influence of anticipatory and early race stress. The effectiveness index, average CGM glucose, and the ingested carbohydrate to injected insulin ratio were compared between the paired sessions through regression. In 9 of 12 races studied, an elevated CGM for the race over the individual training session was observed. The rate of change of the CGM during the first 30 minutes of exercise notably differed between the race and training (p = 0.02) with a less rapid decline in CGM occurring during the race for 11 of 12 paired sessions and an increasing CGM trend during the race for 7 of the 12 sessions with the rate of change (mean ± standard deviation) as 1.36 ± 6.07 and -2.59 ± 2.68 mg/dL per 5 minutes for the race and training, respectively. Individuals with longer durations of diabetes often decreased their carbohydrate-to-insulin ratio on race day, taking more insulin, than on the training day while the reverse was noted for those newly diagnosed (r = -0.52, p = 0.05). The presence of athletic competition stress can impact glycemia. With an increasing duration of diabetes, the athletes may be expecting elevated competition glucose concentrations and take preventive measures.

Optimized Clinical Strategies for Treatment-Resistant Depression: Integrating Ketamine Protocols with Trauma- and Attachment-Informed Psychotherapy

Strategically timed trauma- and attachment-informed psychotherapy to address underlying emotional wounds, paired with ketamine administered in precision-calibrated doses to ensure high-entropy brain states, may be key to improving the quality and duration of ketamine’s therapeutic efficacy for treatment-resistant depression. This approach optimizes the opportunities for change created by ketamine’s known effects as a rapid antidepressant that stimulates synaptogenesis, normalizes neural connectivity and coherence, enhances neuroplasticity, reduces inflammation, and induces high-entropy brain states with associated subjective psychedelic experiences. Ketamine, a non-selective N-methyl-D-aspartate (NMDA) receptor antagonist is a safe, effective, fast-acting dissociative anesthetic that, as a standalone treatment, also exhibits rapid sustained antidepressant effects, even in many patients with treatment-resistant depression. A prior history of developmental trauma and attachment injuries are known primary factors in the etiology of treatment resistance in depression and other mental disorders. Thus, the adjunct of targeted psychotherapy attuned to trauma and attachment injuries may enhance and prolong ketamine efficacy and provide an opportunity for lasting therapeutic change. Psychotherapy engagement during repeated ketamine sessions for patient safety and integration of altered states, paired with separate individualized psychotherapy-only sessions timed 24–48 h post ketamine induction, takes advantage of peak ketamine-induced dendritic spine growth in the prefrontal cortex and limbic system, and normalized network connectivity across brain structures. This strategically timed paired-session approach also exploits the therapeutic potential created by precision-calibrated ketamine-linked high-entropy brain states and associated psychedelic experiences that are posited to disrupt overly rigid maladaptive thoughts, behaviors, and disturbing memories associated with treatment-resistant depression; paired sessions also support integration of the felt sense of happiness and connectivity associated with psychedelic experiences.

Comparison of Performance Score for Female and Male Residents in General Surgery Doing Supervised Real-Life Laparoscopic Appendectomy: Is There a Norse Shield-Maiden Effect?

BackgroundGender bias may represent a threat to resident assessment during surgical training, and there have been concerns that women might be disadvantaged. There is a lack of studies investigating gender differences in ‘entry-level’ real-life procedures, such as laparoscopic appendectomy. We aimed to explore potential gender disparities in self-evaluation and faculty evaluation of a basic surgical procedure performed by junior surgical residents in general surgery.MethodsA structured training program in laparoscopic appendectomy was implemented before undertaking evaluation of real-life consecutive laparoscopic appendectomies by junior residents in general surgery. Resident and faculty gender-pairs were assessed. Intraclass correlation coefficient (ICC) was calculated using a single-rater, consistency, 2-way mixed-effects model.ResultsA total of 165 paired sessions were completed to evaluate resident–faculty scores for the procedure. Overall, 19 residents participated (43% women) and 26 faculty (42% women) were involved. The overall correlation between faculty and residents was good (ICC > 0.8). The female–female pairs scored higher for most steps, achieving excellent (ICC ≥ 0.9) for several steps and for overall performance. Female residents were more likely to give a higher self-evaluated score on own performance particularly if evaluated by a female faculty. Also, female trainees had highest correlation-score with male faculty.ConclusionsThis study found higher performance scores in female surgical residents evaluated during real-time laparoscopic appendectomy. No negative gender bias toward women was demonstrated. Better insight into the dynamics of gender-based interaction and dynamics in both training, feedback and influence on evaluation during training is needed when evaluating surgical training programs.

Effect of nipple shield use on milk removal: a mechanistic study

BackgroundConcerns about reduced milk transfer with nipple shield (NS) use are based on evidence from studies with methodological flaws. Milk removal during breastfeeding can be impacted by infant and maternal factors other than NS use. The aim of this study was to control electric breast pump vacuum strength, pattern and duration across multiple study sessions to determine if NS use reduces milk removal from the breast.MethodsA within-subject study with two groups of breastfeeding mothers (infants < 6 months) were recruited; Control Group (CG): no breastfeeding difficulties; Pain Group (PG) used NS for persistent nipple pain. Mothers completed three randomised 15 min pumping sessions using the Symphony vacuum curve (Medela AG); no NS, fitted NS, and a small NS. Sessions were considered valid where the applied vacuum was within 20 mmHg of the set vacuum. Milk removal was considered as pumped milk volume, and also percentage of available milk removed (PAMR), which is calculated as the pumped volume divided by the estimated milk volume stored in the breast immediately prior to pumping.ResultsOf 62 sessions (all: n = 31 paired sessions) a total of 11 paired sessions from both PG (n = 03) and CG (n = 08) were valid (subset) with and without a fitted NS. Only 2 small shield sessions were valid and so all small shield measurements were excluded. Both pumped volumes and PAMR were significantly lower with NS use for all data but not for subset data. (All: Volume and PAMR median: no NS: 76.5 mL, 69%, Fitted NS: 32.1 mL, 41% respectively (volume p = 0.002, PAMR p = 0.002); Subset: Volume and PAMR median: no NS: 83.8 mL, 72%; Fitted NS: 35.2 mL, 40% (volume p = 0.111 and PAMR p = 0.045). The difference in PAMR, but not volume, was statistically significant when analysed by linear mixed modelling. A decrease of 10 mmHg was associated with a 4.4% increase in PAMR (p = 0.017).ConclusionsThis experimental data suggests that nipple shield use may reduce milk removal. Close clinical monitoring of breastfeeding mothers using nipple shields is warranted.

Non-invasive Brain Stimulation Paired with Standard Physical Therapy in Parkinson's Disease: A Pilot Feasibility Trial

Introduction: In Parkinson’s disease (PD), postural imbalance and gait disorders (PIGD) are predictors of decreased quality of life and survival. PIGD often become unresponsive to pharmacological treatments and are commonly associated with cognitive dysfunction. Physical therapy (PT) training and falls prevention education are considered effective treatments; however, improvements are generally short-lived and only partially maintained. In this population, cognitive dysfunction hampering the consolidation of new motor skills (motor learning) is one principal reason. Transcranial magnetic stimulation (TMS) is an emerging tool for neuro-rehabilitation and growing evidence supports its potential to improve motor learning. Prompted by a shared location between our TMS lab and the PT rehabilitation center, we aimed to test whether adjuvant repetitive TMS combined with PT for PIGD is a feasible neuro-rehabilitation paradigm in patients with PD. Methods: Double blind, randomized, sham-controlled, pilot trial to evaluate the feasibility of recruitment, randomization, retention, assessment procedures and implementation of adjuvant TMS paired back-toback with PT in PD patients with PIGD. Result: 41 paired sessions were completed with 100% adherence. All sessions were tolerated. There were no severe adverse events. One subject withdrew consent. Blinding of study was deemed adequate. The average time between PT and TMS administration was 13.9 (SD 7.3) minutes. After completion of the 5th enrolled subject, the study was early terminated due to relocation of the PD center away from the PT facility. Clinical outcome mean values improved at follow up; however, the small sample size prevented further analysis of efficacy. Conclusions: When the TMS device is located in the proximity of a rehabilitation setting, adjuvant TMS appears to be feasible, safe, and well tolerated in PD. The efficacy of this modality of neuro-rehabilitation and its generalizability remain to be determined.

Towards crossing the borders in foreign language teacher training: A report on a pilot phase of the Tandem Learning for Teacher Training project

The aim of the paper is to present the results of a pilot project for foreign language (FL) teacher education, in which trainee teachers’ knowledge and awareness of intercultural and cross-educational similarities and differences between two cooperating institutions from socio-culturally and linguistically distant countries – Israel and Poland – are elicited. The data collected serves as a springboard for designing an international project for FL trainee teachers to be implemented as a part of a teacher training course. In the project the trainee teachers coming from geographically, culturally and linguistically detached backgrounds, Israeli and Polish, are to participate in tandem learning understood as paired sessions of knowledge and experience exchange between FL trainee teachers via online communicators. The pilot phase, therefore, is an initial but indispensable stage evaluating the extent to which trainee teachers are ready to confront and share their educational background, cultural and linguistic knowledge with their peers from a geographically and socio-culturally distant country. A group of fourteen trainee teachers of Opole University participated in the pilot project measuring the participants’ readiness to engage in crossing the aforementioned borders with the help of a closed and open-item questionnaire focusing on the degrees of awareness of a number of aspects, for instance, culture and L1-based differences in approaching FL teaching. The application of the instrument generated quantitative and qualitative data, whose analysis supported the design of the final Tandem Learning Teacher Training (TLTT) program.

Developmental Changes in Hippocampal CA1 Single Neuron Firing and Theta Activity during Associative Learning.

Hippocampal development is thought to play a crucial role in the emergence of many forms of learning and memory, but ontogenetic changes in hippocampal activity during learning have not been examined thoroughly. We examined the ontogeny of hippocampal function by recording theta and single neuron activity from the dorsal hippocampal CA1 area while rat pups were trained in associative learning. Three different age groups [postnatal days (P)17-19, P21-23, and P24-26] were trained over six sessions using a tone conditioned stimulus (CS) and a periorbital stimulation unconditioned stimulus (US). Learning increased as a function of age, with the P21-23 and P24-26 groups learning faster than the P17-19 group. Age- and learning-related changes in both theta and single neuron activity were observed. CA1 pyramidal cells in the older age groups showed greater task-related activity than the P17-19 group during CS-US paired sessions. The proportion of trials with a significant theta (4–10 Hz) power change, the theta/delta ratio, and theta peak frequency also increased in an age-dependent manner. Finally, spike/theta phase-locking during the CS showed an age-related increase. The findings indicate substantial developmental changes in dorsal hippocampal function that may play a role in the ontogeny of learning and memory.

Self-Corrected Comprehension of Near-Synonymous Verbs Via Comparative Visualizations

Building from previous studies, this paper explores the nature of English conceptual structure of state differentiation for the holding/carrying near-synonyms in random and paired sessions. To test for such conceptual differences, Imai & Saji’s (2013) instrument was adopted where 56 monolingual English speakers were asked to name the holding/carrying near-synonyms in random and paired sessions. In each session, the order of stimuli presentation was manipulated. In random session, the stimuli was randomized in a way that a holding action may or may not be successively followed by a carrying action; whereas, in the paired session, the stimuli was paired in a way that a holding action must be successively followed by a carrying action. The qualitative data were coded to indicate multiple cognitive categories as to how state and manner distinctions were perceived for further quantitative analysis. Overall, the results demonstrated that native English speakers have a differentiated conceptual structure for the state of holding and carrying near-synonyms and that structure is sensitive to the order of stimuli presentation. Implications for such results were discussed in terms of near-synonymous difficulty and pedagogical recommendations for L2 English learners.

Prevention of blindness due to retinopathy of prematurity: a national movement.

Retinopathy of Prematurity (ROP) has been a blinding disorder and a preventable cause of childhood blindness. With growing interest in pediatric ophthalmology and vitreo-retinal subspecialty, ROP has become increasingly recognized in India. Recently, with rise in number of children admitted to NICU's across India, there has been an increase in number of preterm babies with ROP due to variable neonatal practices. An effort to prevent the disease was taken up by WHO and Ministry of Health & Family Welfare by conducting workshops across India piloted by R.P. Centre, AIIMS. These workshops have gone a long way in spreading awareness amongst both neonatologists and ophthalmologists in paired sessions. Both neonatologists and ophthalmologists complemented each other, discussed ROP prevention and issued ROP screening and good neonatal care guidelines which were different from the American guidelines. Treatment strategies have also undergone a huge change from cryotherapy and laser to anti-vascular endothelial growth factor (Anti-VEGF) drugs which have shown promising results, although caution is to be taken due to lack of data on long-term safety. Overall impact of these workshops led to inclusion of ROP in priority list of blindness control programme of Government of India. Still, ROP prevention needs integration of both governmental and non-governmental agencies, each sharing the load in a complementing way aiding in downward trends of ROP cases.

Nitric oxide in central amygdala potentiates expression of conditioned withdrawal induced by morphine

Objective:The aim of this study was to evaluate if nitric oxide (NO) in the central amygdala (CeA) is involved in the expression of withdrawal aspects induced by morphine.Materials and Methods:Male Wistar rats (weighing 200-250 g) were bilaterally cannulated in the CeA and conditioned to morphine using an unbiased paradigm. Morphine (2.5-10 mg/kg) was subcutaneously injected once a day throughout the conditioning phase of the procedure. This phase also included 3-saline paired sessions. Naloxone (0.1-0.4 mg/kg, intraperitoneally [i.p.]), an antagonist of opioid receptors, was administered i.p. 10 min prior to testing of morphine-induced withdrawal features. The NO precursor, L-arginine (0.3-3 μg/rat) was intra-CeA injected prior to testing of naloxone response. To evaluate the involvement of NO system an inhibitor of NO synthase (NOS), NG-nitro-L-arginine methyl ester (L-NAME) (0.3-3 μg/rat), was injected ahead of L-arginine. Control group received saline solely instead of drug. As a complementary study, the activation of NOS was studied by nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d).Results:Morphine induced a significant increase in wet dog shaking and grooming behaviors compared with controls. Injection of naloxone pre-testing of morphine response significantly reversed the response to morphine. However, pre-microinjection of L-arginine intra-CeA recovered the response to morphine. Injection of L-NAME intra-CeA ahead of L-arginine though had no effect behaviorally, but, inhibited the NOS which has been evidenced by NADPH-d.Conclusion:The present study shows that NO in the CeA potentiates the expression of conditioned withdrawal induced by morphine paired with naloxone.

Pediatrics Residents' Preparedness for Neonatal Resuscitation Assessed Using High-Fidelity Simulation

Pediatrics residents are expected to demonstrate preparedness for neonatal resuscitation, yet research has shown gaps in residents' readiness to perform this skill. To evaluate procedural skills and team performance of pediatrics residents during neonatal resuscitation (NR) using a high-fidelity mannequin, and to assess residents' confidence in their NR skills before and after training. Two teams of residents (all had completed NR program training) participated in 2 separate, 90-minute sessions (2 to 3weeks apart) in an off-site delivery room during their neonatal intensive care rotation. Residents' confidence in assisting and leading NR was surveyed before each session. Teams participated in a scenario (adapted from the NR program), which required 5 skills (positive pressure ventilation, chest compressions, endotracheal intubation, umbilical vein catheterization, and epinephrine administration). Video recording was used for debriefing and scoring. Skills were scored for technique and timeliness, and team behaviors were scored for communication, management, and leadership. Twenty-six residents (11 teams) completed 2 paired sessions. Self-confidence scores increased between the 2 sessions but were not correlated with performance. Gaps in procedural skill performance were observed, and timeliness for most skills did not meet expectations. Significant improvement in team communication was noted. Important gaps in procedural skill performance, particularly timeliness, were detected by NR simulation training; residents' improvements in self-confidence did not reflect gains in actual performance. Their relative unpreparedness for NR (despite prior certification) highlights the need for deliberate practice and specific team training before and during neonatal intensive care delivery room rotations.

Abuse liability and reinforcing efficacy of oral tramadol in humans

BackgroundTramadol, a monoaminergic reuptake inhibitor, is hepatically metabolized to an opioid agonist (M1). This atypical analgesic is generally considered to have limited abuse liability. Recent reports of its abuse have increased in the U.S., leading to more stringent regulation in some states, but not nationally. The purpose of this study was to examine the relative abuse liability and reinforcing efficacy of tramadol in comparison to a high (oxycodone) and low efficacy (codeine) opioid agonist. MethodsNine healthy, non-dependent prescription opioid abusers (6 male and 3 female) participated in this within-subject, randomized, double blind, placebo-controlled study. Participants completed 14 paired sessions (7 sample and 7 self-administration). During each sample session, an oral dose of tramadol (200 and 400mg), oxycodone (20 and 40mg), codeine (100 and 200mg) or placebo was administered, and a full array of abuse liability measures was collected. During self-administration sessions, volunteers were given the opportunity to work (via progressive ratio) for the sample dose or money. ResultsAll active doses were self-administered; placebo engendered no responding. The high doses of tramadol and oxycodone were readily self-administered (70%, 59% of available drug, respectively); lower doses and both codeine doses maintained intermediate levels of drug taking. All three drugs dose-dependently increased measures indicative of abuse liability, relative to placebo; however, the magnitude and time course of these and other pharmacodynamic effects varied qualitatively across drugs. ConclusionsThis study demonstrates that, like other mu opioids, higher doses of tramadol function as reinforcers in opioid abusers, providing new empirical data for regulatory evaluation.

Stimulation of the lateral geniculate, superior colliculus, or visual cortex is sufficient for eyeblink conditioning in rats.

The role of the cerebellum in eyeblink conditioning is well established. Less work has been done to identify the necessary conditioned stimulus (CS) pathways that project sensory information to the cerebellum. A possible visual CS pathway has been hypothesized that consists of parallel inputs to the pontine nuclei from the lateral geniculate nucleus (LGN), superior colliculus (SC), pretectal nuclei, and visual cortex (VCTX) as reported by Koutalidis and colleagues in an earlier paper. The following experiments examined whether electrical stimulation of neural structures in the putative visual CS pathway can serve as a sufficient CS for eyeblink conditioning in rats. Unilateral stimulation of the ventral LGN (Experiment 1), SC (Experiment 2), or VCTX (Experiment 3) was used as a CS paired with a periorbital shock unconditioned stimulus. Stimulation was delivered to the hemisphere contralateral to the conditioned eye. Rats in all experiments were given five 100-trial sessions of paired or unpaired eyeblink conditioning with the stimulation CS followed by three paired sessions with a light CS. Stimulation of each visual area when paired with the unconditioned stimulus supported acquisition of eyeblink conditioned responses (CRs) and substantial savings when switched to a light CS. The results provide evidence for a unilateral parallel visual CS pathway for eyeblink conditioning that includes the LGN, SC, and VCTX inputs to the pontine nuclei.

A Case Report of Double‐Filtration Plasmapheresis for the Treatment of Age‐related Macular Degeneration

An 85-year-old man with dry type age-related macular degeneration (AMD) in his right eye and a disciform scar in his left eye received double-filtration plasmapheresis (DFPP) for the treatment of his right eye. The protocol for plasmapheresis followed the Multicenter Investigation of Rheopheresis for AMD (MIRA) trial and consisted of four pulses of paired sessions of plasmapheresis with a two-day interval within 10 weeks. The pre-DFPP best corrected visual acuity (BCVA) for the right eye was 6/15 (0.4). Six months after DFPP treatment, the BCVA of the right eye was 6/10 (0.6) and remained unchanged at the 12th month; however, comparison of the right eye fundus picture, fluorescein angiogram, and optical coherence tomography of the macular area before and 6 and 12 months after plasmapheresis revealed no discernable changes. The per-session and per-course clearance rates were highest for IgM (63.8% and 90.8%) and lowest for albumin (11% and 15.4%). No plasmapheresis-related complications, such as hypotension, hemolysis or infection, occurred. Thus, DFPP treatment can provide effective treatment for dry type AMD with minimal side-effects.

Effect of Experimental Influenza A Infection on the Nasal Response to Histamine Challenge in Allergic and Non-Allergic Subjects

To determine if a viral upper respiratory tract infection can alter the responsiveness of the nasal mucosa, paired intranasal histamine challenge sessions were performed before and after (8 days) intranasal inoculation with influenza A virus in 16 nonallergic and 16 allergic subjects. The nasal response to a 1-mg histamine challenge was measured as symptom scores for rhinorrhea and congestion, counts for sneezing, weight for expelled secretions, and inspiratory conductance for nasal patency. After inoculation, a total of 25 subjects (11 allergic, 14 nonallergic) became infected with influenza A virus. In infected subjects the measured responses to histamine for secretion weight and rhinorrhea symptom score were significantly greater at 8 days postinfection when compared to those responses recorded prior to inoculation. No significant between session differences were observed for the other responses, or for any of the responses in the uninfected subjects. Significant differences between infected allergic and nonallergic subjects were not observed for any response. These results document an increased secretory response of the nose to histamine during the postsymptomatic period of influenza A viral infection in both allergic and nonallergic subjects.

Changes in motor responses induced by cerebellar stimulation during classical forelimb flexion conditioning in cat.

1. The ability of somaesthetic sensory inputs to produce structural changes in the connectivities of the central nervous structures involved in motor activity was tested with an alpha type of classical conditioning in chronically prepared adult cats. Repetitive sensory stimulation was applied at constant intervals after the activation of the motor circuits originating in the neurons or efferent axons of the cerebellar nuclei. A conditional stimulation (CS) applied to interpositus neurons was consistently paired with an unconditional stimulation (UCS) applied to the dorsal skin of the forelimb extremity to induce associative sensorimotor conditioning. The sites at which the conditional and unconditional stimuli were applied set up a simplified sensorimotor circuit including pathways transmitting both these stimuli and others mediating the expression of the conditioned responses. 2. To test the changes resulting from the conditioning, electrodes were implanted into the various relay structures on the cerebellar efferent pathways (ventrolateral nucleus motor cortex). The forelimb motor responses elicited by stimulating these relay structures were recorded with a potentiometer placed at the elbow joint. The angular displacement (amplitude) and latency of the responses and the percentage response rates were systematically quantified throughout the conditioning procedure and at test sessions carried out after the daily conditioning routines. 3. It was observed that daily repetition of paired CS-UCS led to an increase in the response rates and amplitudes of the forelimb flexions, which already began to occur very slightly on the first 4 or 5 days in response to the alpha conditioning, whereas the CS when applied alone failed to produce any changes in this initial response. Likewise, after the acquisition phase, repeated presentation of either the CS alone or the CS preceded by the UCS led to the extinction of the conditioned response, thus indicating that the observed changes were of an associative nature and that they depended on interactions between the motor and sensory inputs occurring somewhere in the CNS. In fact, the effects of conditioning were not generalized, but involved only a circumscribed circuit originating in the cerebellar neurons stimulated by the CS, which were activated concomitantly with the sensory pathways. 4. The conditioned response amplitudes were enhanced by 2.5-3 times their initial value. This enhancement persisted at the end of acquisition or after several days of consolidation, even when the paired CS-UCS sessions were interrupted for a period of 15 days to 2 mo.(ABSTRACT TRUNCATED AT 400 WORDS)

Conditioned orienting (alpha) and delayed behavioral and evoked neural responses during classical conditioning

A differentiation of short-latency (alpha) and long-latency (delayed) classically conditioned behavioral and evoked neural (hippocampal) responses was attempted. Further, facilitation and retardation of these responses were studied in an experimental design in which 10 paired conditioning sessions either preceded (CC-CO group) or followed (CO-CC group) 10 randomly unpaired presentations of conditioned stimuli (CS) and unconditioned stimuli (UCS). A 2024-ms tone (1000 Hz) was delivered directly through a miniature earphone to the left ear, eliciting an orienting head movement ('alpha' response) to the left. The unconditioned stimulus (UCS) was a direct 1024-ms stimulation of the lateral hypothalamic area overlapping the CS (delayed paradigm) so that both stimuli terminated simultaneously. The UCS elicited approach behavior and a specific head movement in each animal. The latency and the direction of the head movement were used as criteria for a differentiation of the short-latency and long-latency conditioned responses (CR). All cats showed conditioned short-latency responses. Pairing specific long-latency head movements were observed in 10 of 13 cats and 6 of them showed a long-latency CR which was a head movement to the right, while the short-latency CR on the same trials was a head movement to the left. Hippocampal (subiculum, dentate fascia and CA1) evoked responses also showed pairing specific CRs appearing as increased negativity (short-latency CR), or increased positivity (long-latency CR). Additional reversed stimulus order (backward) sessions supported an assumption of the different nature of the short-latency and long-latency CRs: the long-latency CRs showed extinction while the short-latency CRs remained. The unpaired pre-exposure to the CSs and UCSs in the CO-CC group resulted in the retarded acquisition of the behavioral responses during the subsequent paired sessions.

Effects of Pairing of Chicks During the Imprinting Period on Filial Responses to an Imprinting Stimulus

There are several studies which have evaluated the effects of social contact with siblings on imprinting to a maternal surrogate. However, we have no consistent effect of the social experience. Some studies have reported that social experience with siblings interferes with the establishment of imprinting, whereas other studies have reported that social experience with siblings enhances the imprinting experience.The present study examined the effects of social contact with one sibling during the imprinting sessions on imprinting to the maternal object for chicks (White Leghorn). This experimental situation is similar to the natural setting because under natural conditions imprinting occurs in a social situation which includes a parent and siblings. Next, this study investigated the interrelation between each chick's responses to its partner and those to the imprinting object.During the imprinting sessions, each chick was individually exposed to only the imprinting object under the isolated condition or exposed to both the stimulus and one sibling under the paired condition over three days after hatching. Each chick showed the better performance under the isolated condition than under the paired condition. Thus the presence of one sibling during the imprinting period weakens the strength of the imprinting.The more interesting result was that chicks who had showed a poor performance under the first paired sessions followed the stimulus well under the later isolated condition. It seems that these subjects have already fully imprinted to the stimulus in spite of poor experience of following the stimulus. This result renders dubious the significance of following as an index of the strength of imprinting.Next, it was often observed under paired conditions that as soon as a well-imprinted chick followed the stimulus, the other chick ran behind him quickly. It was also observed that this well-imprinted chick followed its partner and pecked at him frequently. We can consider there is some interrelation between social responses to a sibling and those to a surrogate mother.

Differential sensitivity to airpuffs on human hairy and glabrous skin.

To compare the relative sensitivities of glabrous and hairy skin, we measured reaction times (RTs) and detectability (d') of airpuffs delivered to the hairy dorsum and glabrous thenar eminence of the hand of six human subjects. In contrast to previous studies with mechanical contact stimuli, airpuffs applied to hairy skin were detected with equal or greater fidelity than airpuffs tested on glabrous skin. Mean RTs to three simultaneously applied airpuffs were significantly shorter (p less than .005) on hairy skin in five of six subjects, and in 74% of paired sessions; no significant difference in mean RTs was observed in 16% of the sessions. The superiority of hairy skin was less evident, however, when single airpuffs were tested, as significantly shorter responses were observed on only 45% of the paired sessions, and nearly identical responses on 38% of the sessions. Detectability of airpuffs (d'), which is independent of the value of RTs, was identical on hairy and glabrous skin at high airpuff intensities (1,600 dyn), and superior (n = 4) or equal (n = 2) on hairy skin with low airpuff intensities (800 dyn). Spatial summation was more pronounced on hairy than on glabrous skin. Three simultaneously presented airpuffs produced significantly shorter RTs than one airpuff in 85% of the paired sessions on hairy skin, but on only half of the sessions on glabrous skin. The spatial distribution of stimulus force was less important on hairy skin, as three low-intensity airpuffs produced the same or shorter RTs than one high-intensity airpuff. By contrast, on glabrous skin, detectability was significantly better when force was concentrated at a single point (1 X 1,600 dyn) than when diffused over a wide skin area (3 X 800 dyn). The enhanced sensitivity of hairy skin to airpuffs appears partially attributable to hair motion in the airstream. After hair removal by chemical depilation, detectability of airpuffs was reduced on hairy skin to a level equal to or below that on glabrous skin. Spatial summation on the depilated skin corresponded to that observed on the intact hairy skin, indicating that depilation did not abolish intensity discrimination, but rather lowered the overall sensitivity of hairy skin. These results show that hair follicle units form a very sensitive detection mechanism on hairy skin of the human hand, similar to that provided by Meissner's and Pacinian afferents in glabrous skin. These findings with airpuffs provide the first example of a tactile stimulus that is less effective for mechanoreceptors in glabrous skin than in hairy skin.(ABSTRACT TRUNCATED AT 400 WORDS)