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Brain Sciences
Volume 2
Issue 4
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Brain Sci., Volume 2, Issue 4 (December 2012) – 17 articles , Pages 434-834

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45 pages, 1425 KB  
Review
Brain. Conscious and Unconscious Mechanisms of Cognition, Emotions, and Language
by Leonid Perlovsky and Roman Ilin
Brain Sci. 2012, 2(4), 790-834; https://doi.org/10.3390/brainsci2040790 - 18 Dec 2012
Cited by 18 | Viewed by 13779
Abstract
Conscious and unconscious brain mechanisms, including cognition, emotions and language are considered in this review. The fundamental mechanisms of cognition include interactions between bottom-up and top-down signals. The modeling of these interactions since the 1960s is briefly reviewed, analyzing the ubiquitous difficulty: incomputable [...] Read more.
Conscious and unconscious brain mechanisms, including cognition, emotions and language are considered in this review. The fundamental mechanisms of cognition include interactions between bottom-up and top-down signals. The modeling of these interactions since the 1960s is briefly reviewed, analyzing the ubiquitous difficulty: incomputable combinatorial complexity (CC). Fundamental reasons for CC are related to the Gödel’s difficulties of logic, a most fundamental mathematical result of the 20th century. Many scientists still “believed” in logic because, as the review discusses, logic is related to consciousness; non-logical processes in the brain are unconscious. CC difficulty is overcome in the brain by processes “from vague-unconscious to crisp-conscious” (representations, plans, models, concepts). These processes are modeled by dynamic logic, evolving from vague and unconscious representations toward crisp and conscious thoughts. We discuss experimental proofs and relate dynamic logic to simulators of the perceptual symbol system. “From vague to crisp” explains interactions between cognition and language. Language is mostly conscious, whereas cognition is only rarely so; this clarifies much about the mind that might seem mysterious. All of the above involve emotions of a special kind, aesthetic emotions related to knowledge and to cognitive dissonances. Cognition-language-emotional mechanisms operate throughout the hierarchy of the mind and create all higher mental abilities. The review discusses cognitive functions of the beautiful, sublime, music. Full article
(This article belongs to the Special Issue The Brain Knows More than It Admits: The Control of Cognition and Emotion by Non-Conscious Processes)
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21 pages, 234 KB  
Article
Defining the Parameters of Incidental Learning on a Serial Reaction Time (SRT) Task: Do Conscious Rules Apply?
by Lynne A. Barker
Brain Sci. 2012, 2(4), 769-789; https://doi.org/10.3390/brainsci2040769 - 17 Dec 2012
Cited by 8 | Viewed by 7454
Abstract
There is ongoing debate about the contribution of explicit processes to incidental learning, particularly attention, working memory and control mechanisms. Studies generally measure explicit process contributions to incidental learning by comparing dual- to single-task sequence learning on some variant of a Serial Reaction [...] Read more.
There is ongoing debate about the contribution of explicit processes to incidental learning, particularly attention, working memory and control mechanisms. Studies generally measure explicit process contributions to incidental learning by comparing dual- to single-task sequence learning on some variant of a Serial Reaction Time (SRT), usually adopting an auditory tone counting task as the secondary task/memory load. Few studies have used secondary working memory stimuli with the SRT task, those that have typically presented secondary stimuli, before, after or between primary task stimuli. Arguably, this design is problematic because participants may potentially “switch” attention between sequential stimulus sources limiting the potential of both tasks to simultaneously index shared cognitive resources. In the present study secondary Visual and Verbal, memory tasks were temporally synchronous and spatially embedded with the primary SRT task for Visual and Verbal dual-task conditions and temporally synchronous but spatially displaced for Visual-Spatial and Verbal-Spatial Above/Below conditions, to investigate modality specific contributions of visual, verbal and spatial memory to incidental and explicit sequence learning. Incidental learning scores were not different as an effect of condition but explicit scores were. Explicit scores significantly and incrementally diminished from the Single-task through Visual-Spatial Below conditions; percentage accuracy scores on secondary tasks followed a significant corresponding pattern suggesting an explicit learning/secondary memory task trade-off as memory demands of tasks increased across condition. Incidental learning boundary conditions are unlikely to substantially comprise working memory processes. Full article
(This article belongs to the Special Issue The Brain Knows More than It Admits: The Control of Cognition and Emotion by Non-Conscious Processes)
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24 pages, 956 KB  
Review
Wnt Signaling in Neurogenesis during Aging and Physical Activity
by Michael Chen and Huong Do
Brain Sci. 2012, 2(4), 745-768; https://doi.org/10.3390/brainsci2040745 - 14 Dec 2012
Cited by 13 | Viewed by 13587
Abstract
Over the past decade, much progress has been made regarding our understanding of neurogenesis in both young and old animals and where it occurs throughout the lifespan, although the growth of new neurons declines with increasing age. In addition, physical activity can reverse [...] Read more.
Over the past decade, much progress has been made regarding our understanding of neurogenesis in both young and old animals and where it occurs throughout the lifespan, although the growth of new neurons declines with increasing age. In addition, physical activity can reverse this age-dependent decline in neurogenesis. Highly correlated with this decline is the degree of inter and intracellular Wnt signaling, the molecular mechanisms of which have only recently started to be elucidated. So far, most of what we know about intracellular signaling during/following exercise centers around the CREB/CRE initiated transcriptional events. Relatively little is known, however, about how aging and physical activity affect the Wnt signaling pathway. Herein, we briefly review the salient features of neurogenesis in young and then in old adult animals. Then, we discuss Wnt signaling and review the very few in vitro and in vivo studies that have examined the Wnt signaling pathways in aging and physical activity. Full article
(This article belongs to the Special Issue Exercise and Brain Function)
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36 pages, 278 KB  
Review
On Aerobic Exercise and Behavioral and Neural Plasticity
by Rodney A. Swain, Kiersten L. Berggren, Abigail L. Kerr, Ami Patel, Caitlin Peplinski and Angela M. Sikorski
Brain Sci. 2012, 2(4), 709-744; https://doi.org/10.3390/brainsci2040709 - 29 Nov 2012
Cited by 35 | Viewed by 16861
Abstract
Aerobic exercise promotes rapid and profound alterations in the brain. Depending upon the pattern and duration of exercise, these changes in the brain may extend beyond traditional motor areas to regions and structures normally linked to learning, cognition, and emotion. Exercise-induced alterations may [...] Read more.
Aerobic exercise promotes rapid and profound alterations in the brain. Depending upon the pattern and duration of exercise, these changes in the brain may extend beyond traditional motor areas to regions and structures normally linked to learning, cognition, and emotion. Exercise-induced alterations may include changes in blood flow, hormone and growth factor release, receptor expression, angiogenesis, apoptosis, neurogenesis, and synaptogenesis. Together, we believe that these changes underlie elevations of mood and prompt the heightened behavioral plasticity commonly observed following adoption of a chronic exercise regimen. In the following paper, we will explore both the psychological and psychobiological literatures relating to exercise effects on brain in both human and non-human animals and will attempt to link plastic changes in these neural structures to modifications in learned behavior and emotional expression. In addition, we will explore the therapeutic potential of exercise given recent reports that aerobic exercise may serve as a neuroprotectant and can also slow cognitive decline during normal and pathological aging. Full article
(This article belongs to the Special Issue Exercise and Brain Function)
25 pages, 254 KB  
Review
Physical Activity, Cognitive Function, and Brain Health: What Is the Role of Exercise Training in the Prevention of Dementia?
by Sara M. Gregory, Beth Parker and Paul D. Thompson
Brain Sci. 2012, 2(4), 684-708; https://doi.org/10.3390/brainsci2040684 - 29 Nov 2012
Cited by 47 | Viewed by 23268
Abstract
Tor preventive measures are necessary to attenuate the increased economic and social burden of dementia. This review will focus on the potential for physical activity and exercise training to promote brain health and improve cognitive function via neurophysiological changes. We will review pertinent [...] Read more.
Tor preventive measures are necessary to attenuate the increased economic and social burden of dementia. This review will focus on the potential for physical activity and exercise training to promote brain health and improve cognitive function via neurophysiological changes. We will review pertinent animal and human research examining the effects of physical activity on cognitive function and neurophysiology. We will discuss cross-sectional and longitudinal studies addressing the relationship between neurocognitive health and cardiorespiratory fitness or habitual activity level. We will then present and discuss longitudinal investigations examining the effects of exercise training on cognitive function and neurophysiology. We will conclude by summarizing our current understanding of the relationship between physical activity and brain health, and present areas for future research given the current gaps in our understanding of this issue. Full article
(This article belongs to the Special Issue Exercise and Brain Function)
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17 pages, 1347 KB  
Article
Cocaine Sensitization Increases Kyphosis and Modulates Neural Activity in Adult Nulliparous Rats
by Benjamin C. Nephew, Martha K. Caffrey, Ada C. Felix-Ortiz and Marcelo Febo
Brain Sci. 2012, 2(4), 667-683; https://doi.org/10.3390/brainsci2040667 - 27 Nov 2012
Cited by 4 | Viewed by 8056
Abstract
Although data from both animals and humans suggests that adult cocaine use can have long term effects on behavior, it is unknown if prior cocaine use affects future maternal behavior in nulliparous females. In the current study, cocaine or saline was administered to [...] Read more.
Although data from both animals and humans suggests that adult cocaine use can have long term effects on behavior, it is unknown if prior cocaine use affects future maternal behavior in nulliparous females. In the current study, cocaine or saline was administered to adult female rats for 10 days, the animals were withdrawn from cocaine for 7 days, and the females were then exposed to donor pups to induce the expression of maternal behavior. Nulliparous females sensitized to cocaine were more likely to retrieve pups, spent more time caring for the pups, and were more likely to express full maternal behavior on day 8 of pup exposure. The fMRI data revealed significant effects of pup exposure in the hippocampal CA1 region, and effects of cocaine in the anterior thalamus and periaqueductal gray. Prior adult cocaine use may have lasting effects on offspring care, and this effect is not dependent on pup mediated effects or the endocrine changes of gestation and lactation. The present findings provide support for the hypothesis that maternal motivation to exhibit maternal behavior is enhanced by prior cocaine sensitization, possibly due to cross sensitization between cocaine and the natural reward of maternal behavior. Full article
(This article belongs to the Special Issue Addiction and Neuroadaptation)
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18 pages, 645 KB  
Article
Cortical Activity during a Highly-Trained Resistance Exercise Movement Emphasizing Force, Power or Volume
by Shawn D. Flanagan, Courtenay Dunn-Lewis, Brett A. Comstock, Carl M. Maresh, Jeff S. Volek, Craig R. Denegar and William J. Kraemer
Brain Sci. 2012, 2(4), 649-666; https://doi.org/10.3390/brainsci2040649 - 20 Nov 2012
Cited by 13 | Viewed by 7301
Abstract
Cortical activity is thought to reflect the biomechanical properties of movement (e.g., force or velocity of movement), but fatigue and movement familiarity are important factors that require additional consideration in electrophysiological research. The purpose of this within-group quantitative electroencephalogram (EEG) investigation was to [...] Read more.
Cortical activity is thought to reflect the biomechanical properties of movement (e.g., force or velocity of movement), but fatigue and movement familiarity are important factors that require additional consideration in electrophysiological research. The purpose of this within-group quantitative electroencephalogram (EEG) investigation was to examine changes in cortical activity amplitude and location during four resistance exercise movement protocols emphasizing rate (PWR), magnitude (FOR), or volume (VOL) of force production, while accounting for movement familiarity and fatigue. EEG signals were recorded during each complete repetition and were then grouped by functional region, processed to eliminate artifacts, and averaged to compare overall differences in the magnitude and location of cortical activity between protocols over the course of six sets. Biomechanical, biochemical, and exertional data were collected to contextualize electrophysiological data. The most fatiguing protocols were accompanied by the greatest increases in cortical activity. Furthermore, despite non-incremental loading and lower force levels, VOL displayed the largest increases in cortical activity over time and greatest motor and sensory activity overall. Our findings suggest that cortical activity is strongly related to aspects of fatigue during a high intensity resistance exercise movement. Full article
(This article belongs to the Special Issue Exercise and Brain Function)
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15 pages, 291 KB  
Article
Aging, Aerobic Activity and Interhemispheric Communication
by Keith M. McGregor, Kenneth M. Heilman, Joe R. Nocera, Carolynn Patten, Todd M. Manini, Bruce Crosson and Andrew J. Butler
Brain Sci. 2012, 2(4), 634-648; https://doi.org/10.3390/brainsci2040634 - 16 Nov 2012
Cited by 17 | Viewed by 8019
Abstract
Recent studies have shown that during unimanual motor tasks, aging adults show bilateral recruitment of primary motor cortex (M1), while younger adults show a suppression of the ipsilateral motor cortex. Additional work has indicated that increased bilateral M1 recruitment in older adults may [...] Read more.
Recent studies have shown that during unimanual motor tasks, aging adults show bilateral recruitment of primary motor cortex (M1), while younger adults show a suppression of the ipsilateral motor cortex. Additional work has indicated that increased bilateral M1 recruitment in older adults may be deleterious when performing some motor tasks. However, higher levels of physical fitness are associated with improved dexterity and fitness may mitigate the loss of both inhibitory and excitatory communication in aging adults. The goal of this study was to assess dexterity and interhemispheric motor communication in physically fit and sedentary middle-age (40–60 years) right handed participants using tests of hand deftness and transcranial magnetic stimulation (TMS). To behaviorally assess the influence of interhemispheric communication on motor performance, participants also perform the coin rotation deftness task while maintaining pinch force with the opposite hand (bimanual condition). We correlated these behavioral measures with the ipsilateral silent period using TMS to assess interhemispheric inhibition. Our results show that the middle-aged adults who were physically fit had better dexterity of their right hand (finger tapping and peg-board). When performing the coin rotation task the fit group had no between hand differences, but the sedentary group’s left hand performance was inferior to the their right hand. We found that better dexterity correlated with ipsilateral silent period duration (greater inhibition) thereby supporting the postulate that fitness improves interhemispheric motor communication. Full article
(This article belongs to the Special Issue Exercise and Brain Function)
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15 pages, 283 KB  
Article
The α1 Antagonist Doxazosin Alters the Behavioral Effects of Cocaine in Rats
by Colin N. Haile, Yanli Hao, Patrick W. O'Malley, Thomas F. Newton and Therese A. Kosten
Brain Sci. 2012, 2(4), 619-633; https://doi.org/10.3390/brainsci2040619 - 13 Nov 2012
Cited by 13 | Viewed by 7969
Abstract
Medications that target norepinephrine (NE) neurotransmission alter the behavioral effects of cocaine and may be beneficial for stimulant-use disorders. We showed previously that the short-acting, α1-adrenergic antagonist, prazosin, blocked drug-induced reinstatement of cocaine-seeking in rats and doxazosin (DOX), a longer-acting α1 antagonist blocked [...] Read more.
Medications that target norepinephrine (NE) neurotransmission alter the behavioral effects of cocaine and may be beneficial for stimulant-use disorders. We showed previously that the short-acting, α1-adrenergic antagonist, prazosin, blocked drug-induced reinstatement of cocaine-seeking in rats and doxazosin (DOX), a longer-acting α1 antagonist blocked cocaine’s subjective effects in cocaine-dependent volunteers. To further characterize DOX as a possible pharmacotherapy for cocaine dependence, we assessed its impact on the development and expression of cocaine-induced locomotor sensitization in rats. Rats (n = 6–8) were administered saline, cocaine (COC, 10 mg/kg) or DOX (0.3 or 1.0 mg/kg) alone or in combination for 5 consecutive days (development). Following 10-days of drug withdrawal, all rats were administered COC and locomotor activity was again assessed (expression). COC increased locomotor activity across days indicative of sensitization. The high dose (1.0 mg/kg), but not the low dose (0.3 mg/kg) of DOX significantly decreased the development and expression of COC sensitization. DOX alone did not differ from saline. These results are consistent with studies showing that α1 receptors are essential for the development and expression of cocaine’s behavioral effects. Results also suggest that blockade of both the development and expression of locomotor sensitization may be important characteristics of possible pharmacotherapies for cocaine dependence in humans. Full article
(This article belongs to the Special Issue Addiction and Neuroadaptation)
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14 pages, 214 KB  
Article
Nucleus Accumbens Volume Is Associated with Frequency of Alcohol Use among Juvenile Justice-Involved Adolescents
by Rachel E. Thayer, Shirley M. Crotwell, Tiffany J. Callahan, Kent E. Hutchison and Angela D. Bryan
Brain Sci. 2012, 2(4), 605-618; https://doi.org/10.3390/brainsci2040605 - 12 Nov 2012
Cited by 13 | Viewed by 6667
Abstract
Differential neural development of structures associated with reward and control systems may underlie risky behavior in adolescence. The nucleus accumbens and orbitofrontal cortex (OFC) have been implicated in substance use behavior, although structural studies have yet to explore specific relationships between nucleus accumbens [...] Read more.
Differential neural development of structures associated with reward and control systems may underlie risky behavior in adolescence. The nucleus accumbens and orbitofrontal cortex (OFC) have been implicated in substance use behavior, although structural studies have yet to explore specific relationships between nucleus accumbens and OFC volumes and alcohol use in adolescence. High resolution structural MRI scans and assessments of recent alcohol use and lifetime substance use were collected in a sample of 168 juvenile justice-involved adolescents to explore whether gray matter volumes were associated with past 3-month quantity and frequency of alcohol use. Gray matter volumes were not associated with average quantity of alcohol use. Accumbens volume was positively associated with past 3-month frequency of drinking, and OFC volume was negatively associated with drinking frequency. Results may suggest that structural differences in regions related to reward and control processing may contribute to risk behavior in adolescence. Full article
(This article belongs to the Special Issue Addiction and Neuroadaptation)
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16 pages, 237 KB  
Article
Effects of Chronic Central Arginine Vasopressin (AVP) on Maternal Behavior in Chronically Stressed Rat Dams
by Alexander J. Coverdill, Megan McCarthy, Robert S. Bridges and Benjamin C. Nephew
Brain Sci. 2012, 2(4), 589-604; https://doi.org/10.3390/brainsci2040589 - 7 Nov 2012
Cited by 19 | Viewed by 7212
Abstract
Exposure of mothers to chronic stressors during pregnancy or the postpartum period often leads to the development of depression, anxiety, or other related mood disorders. The adverse effects of mood disorders are often mediated through maternal behavior and recent work has identified arginine [...] Read more.
Exposure of mothers to chronic stressors during pregnancy or the postpartum period often leads to the development of depression, anxiety, or other related mood disorders. The adverse effects of mood disorders are often mediated through maternal behavior and recent work has identified arginine vasopressin (AVP) as a key neuropeptide hormone in the expression of maternal behavior in both rats and humans. Using an established rodent model that elicits behavioral and physiological responses similar to human mood disorders, this study tested the effectiveness of chronic AVP infusion as a novel treatment for the adverse effects of exposure to chronic social stress during lactation in rats. During early (day 3) and mid (day 10) lactation, AVP treatment significantly decreased the latency to initiate nursing and time spent retrieving pups, and increased pup grooming and total maternal care (sum of pup grooming and nursing). AVP treatment was also effective in decreasing maternal aggression and the average duration of aggressive bouts on day 3 of lactation. Central AVP may be an effective target for the development of treatments for enhancing maternal behavior in individuals exposed to chronic social stress. Full article
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16 pages, 282 KB  
Article
Cocaine-Induced Reinstatement of a Conditioned Place Preference in Developing Rats: Involvement of the D2 Receptor
by Kimberly A. Badanich and Cheryl L. Kirstein
Brain Sci. 2012, 2(4), 573-588; https://doi.org/10.3390/brainsci2040573 - 31 Oct 2012
Cited by 4 | Viewed by 7657
Abstract
Reinstatement of conditioned place preferences have been used to investigate physiological mechanisms mediating drug-seeking behavior in adolescent and adult rodents; however, it is still unclear how psychostimulant exposure during adolescence affects neuron communication and whether these changes would elicit enhanced drug-seeking behavior later [...] Read more.
Reinstatement of conditioned place preferences have been used to investigate physiological mechanisms mediating drug-seeking behavior in adolescent and adult rodents; however, it is still unclear how psychostimulant exposure during adolescence affects neuron communication and whether these changes would elicit enhanced drug-seeking behavior later in adulthood. The present study determined whether the effects of intra-ventral tegmental area (VTA) or intra-nucleus accumbens septi (NAcc) dopamine (DA) D2 receptor antagonist infusions would block (or potentiate) cocaine-induced reinstatement of conditioned place preferences. Adolescent rats (postnatal day (PND 28–39)) were trained to express a cocaine place preference. The involvement of D2 receptors on cocaine-induced reinstatement was determined by intra-VTA or intra-NAcc infusion of the DA D2 receptor antagonist sulpiride (100 μM) during a cocaine-primed reinstatement test (10 mg/kg cocaine, i.p.). Infusion of sulpiride into the VTA but not the NAcc blocked reinstatement of conditioned place preference. These data suggest intrinsic compensatory mechanisms in the mesolimbic DA pathway mediate responsivity to cocaine-induced reinstatement of a conditioned place preference during development. Full article
(This article belongs to the Special Issue Addiction and Neuroadaptation)
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20 pages, 442 KB  
Article
Striatal Volume Increases in Active Methamphetamine-Dependent Individuals and Correlation with Cognitive Performance
by Reem K. Jan, Joanne C. Lin, Sylvester W. Miles, Rob R. Kydd and Bruce R. Russell
Brain Sci. 2012, 2(4), 553-572; https://doi.org/10.3390/brainsci2040553 - 30 Oct 2012
Cited by 49 | Viewed by 9651
Abstract
The effect of methamphetamine (MA) dependence on the structure of the human brain has not been extensively studied, especially in active users. Previous studies reported cortical deficits and striatal gains in grey matter (GM) volume of abstinent MA abusers compared with control participants. [...] Read more.
The effect of methamphetamine (MA) dependence on the structure of the human brain has not been extensively studied, especially in active users. Previous studies reported cortical deficits and striatal gains in grey matter (GM) volume of abstinent MA abusers compared with control participants. This study aimed to investigate structural GM changes in the brains of 17 active MA-dependent participants compared with 20 control participants aged 18–46 years using voxel-based morphometry and region of interest volumetric analysis of structural magnetic resonance imaging data, and whether these changes might be associated with cognitive performance. Significant volume increases were observed in the right and left putamen and left nucleus accumbens of MA-dependent compared to control participants. The volumetric gain in the right putamen remained significant after Bonferroni correction, and was inversely correlated with the number of errors (standardised z-scores) on the Go/No-go task. MA-dependent participants exhibited cortical GM deficits in the left superior frontal and precentral gyri in comparison to control participants, although these findings did not survive correction for multiple comparisons. In conclusion, consistent with findings from previous studies of abstinent users, active chronic MA-dependent participants showed significant striatal enlargement which was associated with improved performance on the Go/No-go, a cognitive task of response inhibition and impulsivity. Striatal enlargement may reflect the involvement of neurotrophic effects, inflammation or microgliosis. However, since it was associated with improved cognitive function, it is likely to reflect a compensatory response to MA-induced neurotoxicity in the striatum, in order to maintain cognitive function. Follow-up studies are recommended to ascertain whether this effect continues to be present following abstinence. Several factors may have contributed to the lack of more substantial cortical and subcortical GM changes amongst MA-dependent participants, including variability in MA exposure variables and difference in abstinence status from previous studies. Full article
(This article belongs to the Special Issue Addiction and Neuroadaptation)
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30 pages, 383 KB  
Review
Neuroadaptation in Nicotine Addiction: Update on the Sensitization-Homeostasis Model
by Joseph R. DiFranza, Wei Huang and Jean King
Brain Sci. 2012, 2(4), 523-552; https://doi.org/10.3390/brainsci2040523 - 17 Oct 2012
Cited by 19 | Viewed by 10514
Abstract
The role of neuronal plasticity in supporting the addictive state has generated much research and some conceptual theories. One such theory, the sensitization-homeostasis (SH) model, postulates that nicotine suppresses craving circuits, and this triggers the development of homeostatic adaptations that autonomously support craving. [...] Read more.
The role of neuronal plasticity in supporting the addictive state has generated much research and some conceptual theories. One such theory, the sensitization-homeostasis (SH) model, postulates that nicotine suppresses craving circuits, and this triggers the development of homeostatic adaptations that autonomously support craving. Based on clinical studies, the SH model predicts the existence of three distinct forms of neuroplasticity that are responsible for withdrawal, tolerance and the resolution of withdrawal. Over the past decade, many controversial aspects of the SH model have become well established by the literature, while some details have been disproven. Here we update the model based on new studies showing that nicotine dependence develops through a set sequence of symptoms in all smokers, and that the latency to withdrawal, the time it takes for withdrawal symptoms to appear during abstinence, is initially very long but shortens by several orders of magnitude over time. We conclude by outlining directions for future research based on the updated model, and commenting on how new experimental studies can gain from the framework put forth in the SH model. Full article
(This article belongs to the Special Issue Addiction and Neuroadaptation)
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19 pages, 221 KB  
Article
Subliminal Affect Valence Words Change Conscious Mood Potency but Not Valence: Is This Evidence for Unconscious Valence Affect?
by Howard Shevrin, Jaak Panksepp, Linda A. W. Brakel and Michael Snodgrass
Brain Sci. 2012, 2(4), 504-522; https://doi.org/10.3390/brainsci2040504 - 17 Oct 2012
Cited by 12 | Viewed by 7912
Abstract
Whether or not affect can be unconscious remains controversial. Research claiming to demonstrate unconscious affect fails to establish clearly unconscious stimulus conditions. The few investigations that have established unconscious conditions fail to rule out conscious affect changes. We report two studies in which [...] Read more.
Whether or not affect can be unconscious remains controversial. Research claiming to demonstrate unconscious affect fails to establish clearly unconscious stimulus conditions. The few investigations that have established unconscious conditions fail to rule out conscious affect changes. We report two studies in which unconscious stimulus conditions were met and conscious mood changes measured. The subliminal stimuli were positive and negative affect words presented at the objective detection threshold; conscious mood changes were measured with standard manikin valence, potency, and arousal scales. We found and replicated that unconscious emotional stimuli produced conscious mood changes on the potency scale but not on the valence scale. Were positive and negative affects aroused unconsciously, but reflected consciously in potency changes? Or were the valence words unconscious cognitive causes of conscious mood changes being activated without unconscious affect? A thought experiment is offered as a way to resolve this dilemma. Full article
(This article belongs to the Special Issue The Brain Knows More than It Admits: The Control of Cognition and Emotion by Non-Conscious Processes)
21 pages, 2085 KB  
Article
Forced Exercise Enhances Functional Recovery after Focal Cerebral Ischemia in Spontaneously Hypertensive Rats
by Sookyoung Park, Jinhee Shin, Yunkyung Hong, Sunmi Kim, Seunghoon Lee, Kanghui Park, Tserentogtokh Lkhagvasuren, Sang-Rae Lee, Kyu-Tae Chang and Yonggeun Hong
Brain Sci. 2012, 2(4), 483-503; https://doi.org/10.3390/brainsci2040483 - 16 Oct 2012
Cited by 21 | Viewed by 9325
Abstract
Caveolin is the principal protein of caveolae and has been implicated in the pathogenesis of cerebral ischemia. To investigate whether changed expression of caveolins has a pivotal role in focal cerebral ischemia, we induced middle cerebral artery occlusion (MCAo)-reperfusion and examined expression of [...] Read more.
Caveolin is the principal protein of caveolae and has been implicated in the pathogenesis of cerebral ischemia. To investigate whether changed expression of caveolins has a pivotal role in focal cerebral ischemia, we induced middle cerebral artery occlusion (MCAo)-reperfusion and examined expression of caveolins, inflammatory activation markers, and mediators of autophagic cell death. We also treated MCAo rats with forced exercise to determine its effects on neurological outcome. Particularly, spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were used to compare the effects of hypertension on focal cerebral ischemia. All MCAo groups showed neurological deficiencies, motor dysfunction, and disruption of balancing ability; however, these pathological changes were more severe in SHR than WKY rats. Expression of caveolins was decreased in MCAo brain tissue, whereas the levels of iNOS and glial fibrillary acidic protein (GFAP) increased. Additionally, LC3-II and beclin-1 levels were elevated in the MCAo groups. Forced exercise attenuated both molecular and behavioral changes in MCAo animals, but SHR rats showed delayed functional recovery and residual molecular changes when compared to WKY rats. These results suggest that forced exercise may be beneficial for promoting functional recovery following cerebral ischemia through caveolin-dependent mechanisms or interactions between caveolins and these signaling molecules in ischemic brain regions. Full article
(This article belongs to the Special Issue Exercise and Brain Function)
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49 pages, 320 KB  
Review
Functional and Structural Brain Changes Associated with Methamphetamine Abuse
by Reem K. Jan, Rob R. Kydd and Bruce R. Russell
Brain Sci. 2012, 2(4), 434-482; https://doi.org/10.3390/brainsci2040434 - 1 Oct 2012
Cited by 45 | Viewed by 11822
Abstract
Methamphetamine (MA) is a potent psychostimulant drug whose abuse has become a global epidemic in recent years. Firstly, this review article briefly discusses the epidemiology and clinical pharmacology of methamphetamine dependence. Secondly, the article reviews relevant animal literature modeling methamphetamine dependence and discusses [...] Read more.
Methamphetamine (MA) is a potent psychostimulant drug whose abuse has become a global epidemic in recent years. Firstly, this review article briefly discusses the epidemiology and clinical pharmacology of methamphetamine dependence. Secondly, the article reviews relevant animal literature modeling methamphetamine dependence and discusses possible mechanisms of methamphetamine-induced neurotoxicity. Thirdly, it provides a critical review of functional and structural neuroimaging studies in human MA abusers; including positron emission tomography (PET) and functional and structural magnetic resonance imaging (MRI). The effect of abstinence from methamphetamine, both short- and long-term within the context of these studies is also reviewed. Full article
(This article belongs to the Special Issue Addiction and Neuroadaptation)
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