Quantitative validation of immunofluorescence and lectin staining using reduced CLARITY acrylamide formulations.

The CLARITY technique enables three-dimensional visualization of fluorescent-labeled biomolecules in clarified intact brain samples, affording a unique view of molecular neuroanatomy and neurocircuitry. It is therefore, essential to find the ideal combination for clearing tissue and detecting the fluorescent-labeled signal. This method requires the formation of a formaldehyde-acrylamide fixative-generated hydrogel mesh through which cellular lipid is removed with sodium dodecyl sulfate. Several laboratories have used differential acrylamide and detergent concentrations to achieve better tissue clearing and antibody penetration, but the potential effects upon fluorescent signal retention is largely unknown. In an effort to optimize CLARITY processing procedures we performed quantitative parvalbumin immunofluorescence and lectin-based vasculature staining using either 4 or 8% sodium dodecyl sulfate detergent in combination with different acrylamide formulas in mouse brain slices. Using both confocal and CLARITY-optimized lightsheet microscope-acquired images, we demonstrate that 2% acrylamide monomer combined with 0.0125% bis-acrylamide and cleared with 4% sodium dodecyl sulfate generally provides the most optimal signal visualization amongst various hydrogel monomer concentrations, lipid removal times, and detergent concentrations.

Greenhouse gases emission from soils under major crops in Northwest India.

Quantification of greenhouse gases (GHGs) emissions from agriculture is necessary to prepare the national inventories and to develop the mitigation strategies. Field experiments were conducted during 2008-2010 at the experimental farm of the Indian Agricultural Research Institute, New Delhi, India to quantify nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions from soils under cereals, pulses, millets, and oilseed crops. Total cumulative N2O emissions were significantly different (P>0.05) among the crop types. Emission of N2O as percentage of applied N was the highest in pulses (0.67%) followed by oilseeds (0.55%), millets (0.43%) and cereals (0.40%). The emission increased with increasing rate of N application (r(2)=0.74, P<0.05). The cumulative flux of CH4 from the rice crop was 28.64±4.40 kg ha(-1), while the mean seasonal integrated flux of CO2 from soils ranged from 3058±236 to 3616±157 kg CO2 ha(-1) under different crops. The global warming potential (GWP) of crops varied between 3053 kg CO2 eq. ha(-1) (pigeon pea) and 3968 kg CO2 eq. ha(-1) (wheat). The carbon equivalent emission (CEE) was least in pigeon pea (833 kg C ha(-1)) and largest in wheat (1042 kg C ha(-1)). The GWP per unit of economic yield was the highest in pulses and the lowest in cereal crops. The uncertainties in emission values varied from 4.6 to 22.0%. These emission values will be useful in updating the GHGs emission inventory of Indian agriculture.

The neuroanatomical basis of understanding sarcasm and its relationship to social cognition.

The authors explored the neurobiology of sarcasm and the cognitive processes underlying it by examining the performance of participants with focal lesions on tasks that required understanding of sarcasm and social cognition. Participants with prefrontal damage (n=25) showed impaired performance on the sarcasm task, whereas participants with posterior damage (n=16) and healthy controls (n=17) performed the same task without difficulty. Within the prefrontal group, right ventromedial lesions were associated with the most profound deficit in comprehending sarcasm. In addition, although the prefrontal damage was associated with deficits in theory of mind and right hemisphere damage was associated with deficits in identifying emotions, these 2 abilities were related to the ability to understand sarcasm. This suggests that the right frontal lobe mediates understanding of sarcasm by integrating affective processing with perspective taking.

Neuroleptics reverse attention asymmetries in schizophrenic patients.

Discussions of hemispheric asymmetry in psychopathology are often confounded by the effects of medication. We examined the effect of neuroleptic drugs on attention asymmetries in acutely psychotic patients admitted for the first time to a psychiatric hospital before the initiation of drug treatment and again after a period of treatment with neuroleptics. Overall performance did not change significantly; however, attention asymmetry was clearly related to the medication status of the patient: unmedicated patients showed inattention to the right hemispace, which changed to more prominent left-sided inattention when medicated. A longer time on medication or a higher daily dose were associated with a shift of inattention from the right to left hemispace. This suggests that neuroleptics may normalize left hemisphere performance, at the expense of deteriorated right hemisphere performance.

Smooth pursuit pattern in schizophrenic patients during cognitive task.

Asymmetries in saccadic pursuit were studied, using EOG, ion 20 schizophrenic patients, as well as in two groups of normal subjects, screened for their patterns of lateral eye movements (LEM). Tracking performance was also examined while subjects were concurrently engaged in performing a cognitive task. Saccadic pursuit among schizophrenic patients was replicated in the present study. No asymmetry was observed in the quality of leftward as compared to rightward tracking. However, solving syllogisms while tracking resulted in further deterioration in tracking performance of the patients, with significantly more saccades and arrests in tracking occurring when following the target to the left as compared to rightward following. Similar asymmetry was observed in one group of controls who are believed to rely more on their left hemisphere on the LEM test, whereas no asymmetry was observed in the performance of the second control group. These results are interpreted as supporting the hypothesis of left hemispheric hyperactivity in schizophrenia. Saccadic pursuit in one subgroup of the normal sample is considered as suggesting that these individuals belong to the high-risk group.

Neuroleptic-induced lateral asymmetry of visual evoked potentials in schizophrenia.

Electrophysiological studies have shown asymmetric brain reactivity in schizophrenia, supporting the hypothesis of left hemisphere hyperarousal in this disease. It may be assumed, therefore, that neuroleptic treatment restores hemispheric balance in schizophrenic patients by selectively suppressing the hyperactive left hemisphere. This hypothesis was tested in the present study which compared bilaterally recorded visual evoked potentials (VEP) in 9 non-medicated patients and 29 schizophrenics treated with various neuroleptic drugs, as well as in 34 normal controls. In medicated patients later VEP components showed enhancement over the right hemisphere as a function of the overall dose (chlorpromazine equivalent) of neuroleptics. Reversed asymmetry was seen in drug-free patients. In view of this result, some amendments of the concept of left hemisphere hyperactivity in schizophrenia are proposed.

Left hemisphere hyperactivity in schizophrenia: abnormality inherent to psychosis or neuroleptic side-effects?

Studies measuring reflective lateral eye movements (LEM) in schizophrenic patients revealed predominance of rightward LEMS, which was interpreted as suggesting left hemisphere overactivation in schizophrenia. In the present study LEM behaviour of medicated schizophrenics was compared to that of non-medicated patients. Rightward LEMs were predominant in a group of patients treated with phenothiazines with piperazine side chains, whereas among schizophrenics treated with non-piperazine drugs leftward LEMs were more predominant. This finding suggests that previous reports on LEM directionality in schizophrenia may have been confounded by neuroleptic medication. The possible effect of piperazine derivatives on hemispheric balance is discussed.

Transient contralateral rotation following unilateral substantia nigra lesion reflects susceptibility of the nigrostriatal system to exhaustion by amphetamine.

Following unilateral 6-OHDA induced SN lesion, a transient period of contralateral rotation has been reported to precede the predominant ipsilateral circling. In order to clarify the nature of this initial contralateral rotation we examined the effect of the duration of recovery period after the lesion, on amphetamine-induced rotational behavior. Three days post lesion, most rats circled predominantly contralaterally to the lesion. Such contralateral rotation may result from either degeneration-induced breakdown of the DA pool, or lesion-induced increase of DA turnover in the spared neurons. A substantial degree of contralateral preference was still evident when amphetamine was administered for the first time 24 days after lesioning, indicating involvement of spared cells in the contralateral rotation. However, regardless of the duration of recovery (and irrespective of either lesion volume, amphetamine dose, or post-lesion motor exercise), amphetamine-induced rotation tended to become gradually more ipsilateral as the observation session progressed, and all rats circled ipsilaterally to the lesion in response to further amphetamine injections. These findings suggest that amphetamine has an irreversible effect on the post-lesion DA pool contributing to contralateral rotation.

Reactive gaze laterality in schizophrenic patients.

Reflective lateral eye movements (LEMs) in response to questions of different categories are indicative of differential hemispheric reactivity. These LEMs were studied in schizophrenic patients and normal subjects, in response to 24 questions (12 visual-emotional and 12 verbal-neutral). Two categories of saccades were observed: short-latency LEMs (S-LEMs) and long-latency LEMs (L-LEMs). S-LEMs are believed to be associated with orienting response mechanism. L-LEMs are considered to be related to decision-making or formulating hemispheric-activity-dependent response strategy. In the present study, a general trend of leftward LEMs was found among normals regardless of the question's category, whereas schizophrenics tended to show predominantly rightward LEMs. This suggests that individual cognitive style, rather than task variables, affects LEM direction. The two types of LEM's and their different involvement in hemispheric activity are discussed.

Neuroleptic effects on interhemispheric and intrahemispheric performance of tactile discrimination tasks by schizophrenic patients.

The contribution of neuroleptic medication to impaired interhemispheric integration of information, and the relationship between the apparent interhemispheric failure and a unilateral dysfunction, were examined in 12 acutely psychotic patients. The patients performed tactile discrimination tasks, under conditions of intrahemispheric and interhemispheric presentation, before the introduction of any antipsychotic medication, and again after a period of treatment with neuroleptics. In unmedicated patients, both unilateral left hemispheric and interhemispheric deficits were found. However, whereas treatment with neuroleptics normalized the unilateral left hemispheric deficit, it did not have any effect on the performance of the interhemispheric tasks. These findings suggest that the impairment in interhemispheric integration is independent of the unilateral dysfunction and is not modulated by treatment with neuroleptics.

Lateralized neuroleptic-induced side effects are associated with asymmetric visual evoked potentials.

Recent studies suggest that neuroleptic drugs may have an asymmetric effect on the two cerebral hemispheres. This effect is reflected by emergence of drug-induced lateralized extrapyramidal side effects and by dose-related alterations in electrophysiological asymmetries. The present study examined the hypothesis that asymmetry of visual evoked potentials (VEPs) is associated with lateralized appearance of neuroleptic-induced parkinsonism or tardive dyskinesia (TD). The asymmetry of the amplitudes of later VEP components was significantly higher in patients with lateralized side effects (n = 8) than in patients with symmetrical side effects (n = 6) or free of extrapyramidal side effects (n = 11). The possibility that VEP asymmetry reflects the differential degree to which the two hemispheres are affected by medication is discussed.

A comparison of levodopa treatment and task demands on visual evoked potentials in hemi-parkinsonism.

In patients with hemi-Parkinsonism the amplitude of visual evoked potential (EP) components was relatively reduced over the hemisphere contralateral to Parkinsonian symptomatology. Chronic levodopa treatment tended to reverse this lateral asymmetry. Before levodopa treatment, participation in a simple attentional task brought about similar EP changes. After levodopa treatment, only patients with left symptomatology responded to the attention task with an enlargement of EP components, largely in the noninvolved hemisphere. These findings suggest that task demands cause changes in the sensory system which are similar to those contributing to "paradoxical kinesia."

Does unilateral dopamine deficit contribute to depression?

A system of emotional control of behavior is believed to be lateralized to the right hemisphere. Given that dopaminergic pathways are involved in affective behavior, depression, which is recognized as an integral part of Parkinson's disease, may be associated with a dopamine imbalance. The present study examined this hypothesis in patients with unilateral symptomatology indicating either left hemisphere parkinsonism (LHP) or right hemisphere parkinsonism (RHP). Sixteen patients were tested on a battery of neuropsychological tests and several scales for evaluating mood. The two groups did not differ significantly on either cognitive or emotional measures. However, RHP patients rated themselves higher on the Present Scale of Cantril, and showed some neglect of the left visual field, as compared to LHP patients.

Exposure to amphetamine after substantia nigra lesion interferes with the process of behavioral recovery.

Recovery from unilateral substantia nigra lesion may be indicated by re-emergence of circling in the pre-lesion preferred direction. Following 6-OHDA-induced lesion of the dominant SN, we examined: (a) The effect of the delay from lesioning on amphetamine-induced rotation asymmetry, and (b) The effect of early post-lesion exposure to amphetamine on later rotation asymmetry. d-Amphetamine was initially injected either 7, 14, 21, or 30 days after lesioning. Transient circling in pre-lesion preferred direction (contralateral to lesioned side) was more frequently encountered on days 7 and 30 after lesioning, as compared to days 14 and 21. The contralateral rotation observed on day 7 is attributed to degeneration-induced DA release, whereas contralateral rotation noted on day 30 is believed to reflect the operation of post-lesion compensatory processes within the spared DA neurons. In response to subsequent amphetamine administration 30 days after lesioning, rats with previous exposure to the drug circled ipsilaterally, whereas most rats given amphetamine for the first time in that session rotated contralaterally to the lesion. These findings suggest that post-lesion administration of amphetamine interferes with the process of recovery.

Cognitive impairments in Parkinson's disease.

The clinical neuropsychologic profiles of patients with Parkinson's disease and patients with SDAT show both overlap and dissociation. Speech, language, and certain memory skills are examples of dissociable differences, especially in the early stages of the disease. Furthermore the presence of depression, evidence of cognitive slowing, and absence of aphasia in patients with Parkinson's disease suggest prominent subcortical involvement. It is probably premature to categorize all of the cognitive changes in patients with Parkinson's disease as subcortical, however. Some skills, such as visuospatial and executive functions, are impaired in both disorders, and although the etiologic bases for task failure may differ for each, this issue remains open-ended. Another problem is that often the evidence for or against the cortical/subcortical distinction is insufficient and in some cases based on a single measure thought to be representative of a given cognitive domain. Most importantly there are few comparative studies that provide unequivocal support for making a cortical/subcortical distinction. Failure to equate for level of cognitive impairment or functional disability between dementias and strict adherence to cross-sectional study designs further compromise efforts to characterize each syndrome precisely. Whitehouse suggested that a prospective study of several different dementias studied in parallel, examining a wide range of cognitive skills, is required before the cortical/subcortical classification scheme can be validated. A critical component is an autopsy program to confirm diagnoses and provide clinicopathologic correlation. It is possible that the diverse nature of the cognitive impairment in patients with Parkinson's disease is not a methodologic artifact but reflects multiple disease subtypes. Ross, Mahler, and Cummings proposed three dementia syndromes in patients with Parkinson's disease: one that is relatively mild and meets the criteria for subcortical dementia, a second that is more severe and shows a wider range of cognitive impairment but is still neuropathologically distinct from SDAT, and a third severe dementia with both subcortical and cortical involvement that may reflect basal ganglia and Alzheimer-type pathology.

Neurophysiological and neuropsychological study of two cases of multiple personality syndrome and comparison with chronic hysteria.

Two cases of multiple personality were studied neurophysiologically and neuropsychologically. Bilateral frontal (Right greater than Left) and left temporal dysfunction was present in both cases, on neuropsychological indicators. Both cases on EEG analysis, were in a state of relative left hemisphere activation, across all cerebral regions and task conditions. The one case who was cured with hypnotherapy, after recovery showed normal left hemisphere functions neuropsychologically but remained in a state of relative left hemisphere activation electrophysiologically. This is in contrast to women with chronic hysteria who exhibit relative right hemisphere activation in all regions and across all conditions. Both patients were unmedicated throughout. A neurophysiological model to account for these findings is presented.

Hemisphere laterality and smooth pursuit in normal individuals.

34 right-handed women of college age who consistently responded with leftward ("left-movers") or rightward ("right-movers") reflective lateral eye movements were tested on spatial and non-spatial syllogisms while engaged in an eye-tracking task. Contrary to expectation, no interaction between tracking direction and syllogism type was observed. Left-movers performed better on all tasks. The results are discussed in relation to hemispheric asymmetry.

Differential effects of aging on two verbal fluency tasks.

The effect of age on verbal fluency was studied in 84 healthy volunteers, ages 45 to 91 years, who performed letter-fluency and semantic-fluency tasks. Older subjects (75 to 91 yr.) performed as well as younger (50 to 64 yr.) on letter fluency but did significantly worse on semantic category fluency. This pattern is similar to that observed in Alzheimer-type dementia.

The effect of a single aerobic training session on cognitive flexibility in late middle-aged adults.

Research has shown that aerobic exercise enhances cognitive function, specifically executive functions. This study examines the effect of acute aerobic exercise on cognitive flexibility - an executive function - in late middle-aged individuals. Fourteen men and 45 women aged 50 - 64, were randomly assigned to moderate exercise (60 % of heart rate reserve), moderately-intense (70 % of heart rate reserve) exercise, and movie-watching control groups after a maximal exercise test. Prior to and following the exercise or control sessions participants performed two cognitive tasks: the Alternate Uses assessing cognitive flexibility and the Digit Span Forward subtest from the Wechsler Adult Intelligence Scale - Revised assessing attention span. Results indicated significant improvement in Alternate Uses in the exercise groups but not in the control group. No group differences were indicated on the Digit Span. These results provide partial support for the benefit of acute aerobic exercise on cognitive flexibility.

Impaired "affective theory of mind" is associated with right ventromedial prefrontal damage.

OBJECTIVE: To examine the hypothesis that patients with ventromedial (VM) frontal lesions are impaired in the affective rather than cognitive facets of theory of mind (ToM). BACKGROUND: Prefrontal brain damage may result in impaired social behavior, especially when the damage involves the orbitofrontal/VM prefrontal cortex (PFC). It has been previously suggested that deficits in ToM may account for such aberrant behavior. However, inconsistent results have been reported, and different regions within the frontal cortex have been associated with ToM impairment. METHOD: The performance of 26 patients with localized lesions in the PFC was compared with responses of 13 patients with posterior lesions and 13 normal control subjects. Three ToM tasks differing in the level of emotional processing involved were used: second-order false belief task, understanding ironic utterances, and identifying social faux pas. RESULTS AND CONCLUSIONS: The results indicated that patients with VM (but not dorsolateral) prefrontal lesions were significantly impaired in irony and faux pas but not in second-order false belief as compared with patients with posterior lesions and normal control subjects. Lesions in the right VM area were associated with the most severe ToM deficit. These results are discussed in terms of the cognitive and affective facets of "mind-reading" processes mediated by the VM cortex.