Monday, August 31, 2009

The peripheral attenton deficit of primary psychopaths

Described as cold, heartless, manipulative, selfish, and low anxiety, primary psychopaths frankly scare the bejesus out of most people including myself. Look at the case of John Wayne Gacy Jr., the American serial killer who took the lives of 33 boys and young men between 1972 to 1978; burying most of the bodies in his crawl space beneath his home. During his sentencing he was quoted to have morbidly joked that the only thing he was guilty of was "running a cemetery without a license". How messed up is that?

Even until the day of his execution, Gacy never expressed any remorse for the atrocities he had committed. Interestingly enough, the lethal chemicals contained in the IV tube leading to his arm unexpectedly solidified, prolonging the execution process. I can't help but believe that on that day karma came back and bit him in the ass...hard (I just wanted to make it clear that I'm not saying all psychopaths are serial killers).

Saturday, August 29, 2009

The association between creativity and suicide

Over the years a number of iconic musicians have met tragic deaths from either an overdose or suicide (e.g. Bradley Nowell and Kurt Cobain from two of my favorite bands); the former a possible mode of the latter.

In light of DJ AM's recent passing, a prescription drug overdose the most likely culprit, and today's commemoration of Michael Jackson's 51st birthday, I couldn't help but ponder the possible associations between creativity, psychopathology, and suicide. Where is that fine line between creative genius and psychopathology? Does it take a severe mood disturbance to produce a truly creative work of the point of self-destruction? Are musicians more vulnerable to psychopathology and at higher risk for attempting suicide? I provide a few abstracts from past studies addressing this fascinating topic.

Friday, August 28, 2009

The search for a quantum psychology

Today I provide you with a few links to information on "quantum psychology" and the various ways people are attempting to integrate the two sciences.

Robert Anton Wilson

The Quantum Psychology Project

Physical Foundations of Quantum Psychology

Mass Density Blog

Thursday, August 27, 2009

Yet another reason not to consume cannabis

In 1936 an exploitation film directed by Louis Gasnier called Reefer Madness was made in an attempt to teach parents about the dangers of cannabis use. It told of fictional highschool students experimenting with the drug and their tragic and utterly ridiculous demise (e.g. manslaughter, rape, suicide). I'm pretty sure the majority of us now know that smoking marijuana will not cause someone to go on a murderous rampage or off themselves just because they're high. However, recent studies have found that cannabis use does have some negative effects on long-term memory.

Puighermanal and her colleagues investigated the possible involvement of the mTOR pathway in the cognitive impairments produced by cannabinoid agonists. mTOR is a type of enzyme that regulates multiple cellular processes such as neural development and long-term modification of synaptic strength. Administering acute amounts of THC (3 or 10 mg per body weight) to mice, they found modulation of the mTOR/p70S6K signaling cascade in the hippocampus and measurable deficits in long-term memory on an object and context recognition test. However, lower doses did not produce any significant effects.

Wednesday, August 26, 2009

Remote Memories finally released from the diabolical grip of Hippocampus

Hippocampus is suspect in its involvement with the evil legion of brain tissue infamously known as The Retrieval Network, relentlessly capturing Recent Memories. A wise oracle, The System-Level Consolidation Model, foretells the transformation of Recent Memories into Remote Memories and their eventual release from the inexorable grip of Hippocampus as they change hands to the sluggish yet more powerful Neocortical Circuitry during a dark and tortuous time known as the Period of Consolidation (if you haven't gotten it yet, I've been attempting to maintain a consistent theme with the ridiculous title of this blog entry...funny what sleep deprivation and 20 odd years of dorkdum will do to a person).

All kidding aside, Takashima et al. at Radboud University Nijmegen of the Netherlands conducted a study testing the standard system-level consoldiation model's hypothesis. They measured brain activity and connectivity during retrieval of face-location associations using an fMRI. Face-location associations were used for three reasons; features of this stimuli lead to distinct neocortical activity in the fusiform gyrus and posterior parietal cortex, binding of between-domain association involves the hippocampus, and a cued-recall paradigm elicits activation of the hippocampus. Two delays were used; 15 minutes and 24 hours including a whole night of sleep.

Tuesday, August 25, 2009

An overnight therapy session...without a therapist

Today I point you toward a fascinating review article by Walker and van der Helm looking at the crucial function of sleep on emotional regulation. Here is a snippet of their abstract:

This review surveys an array of diverse findings across basic and clinical research domains, resulting in a convergent view of sleep-dependent emotional brain processing. On the basis of the unique neurobiology of sleep, the authors outline a model describing the overnight modulation of affective neural systems and the (re)processing of recent emotional experiences, both of which appear to redress the appropriate next-day reactivity of limbic and associated autonomic networks. Furthermore, a rapid eye movement (REM) sleep hypothesis of emotional-memory processing is proposed, the implications of which may provide brain-based insights into the association between sleep abnormalities and the initiation and maintenance of mood disturbances.

Sleep FTW!

Walker, M., & van der Helm, E. (2009). Overnight therapy? The role of sleep in emotional brain processing. Psychological Bulletin, 135 (5), 731-748 DOI: 10.1037/a0016570

Monday, August 24, 2009

Bid farewell to sleep deprivation's adverse effects on memory

Graveyard shifts and all-night cram sessions are probably some of the worst things you can do to your brain and body. I know because sadly I've done both more times than I can count. It is well known in the sleep field that chronic sleep deprivation accelerates the adverse effects of aging (damn these premature wrinkles), causes emotional dysregulation, and significantly impairs memory.

However, Chua et al. over at the Duke-NUS Graduate Medical School in Singapore seem to have discovered a miracle drug that helps sleep-deprived individuals protect episodic memory; memory consisting of autobiographical events such as times, places, and associated emotions. They found that Donepezil, a cholinesterase inhibitor, reduced episodic memory impairment in 24 hour sleep-deprived healthy young subjects.

Friday, August 21, 2009

Tone deaf? blame it on poor connectivity

Tone deafness is defined as the inability to discriminate between musical notes also known as amusia, tune deafness, dysmelodia, and dysmusia. Famous leaders including President Theodore Roosevelt and Ernesto "Che" Guevara have suffered from this often embarrassing hearing impairment. In an epic fail, Che once tried to woo some chicas at a dance by performing a tango while the band was playing a lively Brazilian (sigh). These are the kinds of people you would never bring to a karaoke bar...unless, of course you were tone deaf too. In that case it wouldn't really matter now would it?

Thursday, August 20, 2009

Did sleepwalking once serve as an adaptive function?

I readily admit that I use to sleepwalk as a kid. My dad once found me laid out at the foot of our considerably large staircase completely unscathed! As I reflect back on those sometimes hazardous, but mostly humorous unconscious experiences I can't help but wonder if somnambulism, the formal term for sleepwalking, once served as some kind of adaptive function. Were our ancient ancestors afforded the opportunity to escape the perils of the wild during states of deep sleep?

There are countless stories of somnambulists executing complex escape behaviors, performing extraordinary feats, and seriously harming others. In 1987 Kenneth Parks drove 15 miles to his in-law's home, beat his father-in-law until he was unconscious, and stabbed his mother-in-law to death...doing all of this while asleep. He later went to the police station stating, "I think I have killed some people". He was covered in blood with a badly injured hand and had absolutely no recollection of what he had done. A year later he was acquitted of murder. Apparently one can get away with a lot on the basis of automatism; even the heinous crime of rape according to Ebrahim at the London Sleep Centre.

Wednesday, August 19, 2009

The consequences of repetitive thought, thought, thought...

I recently stumbled upon an interesting review by Watkins on the constructive and unconstructive consequences of repetitive thought (RT). He mentions a number of thought processes involved in this concept refined by Segerstrom in 2003 including rumination, worry, perseverative cognition, cognitive and emotional processing, counterfactual thinking, mind wandering, defensive pessimism, and habitual negative self-thinking.

His review of the research literature reveals that the main constructive consequences of RT are recovery from trauma and the ability to plan ahead while the unconstructive consequences are depression and anxiety. Three main factors seem to determine the consequences of your RT; the valence or emotional value of the thought content, the interpersonal and situational context in which you are in while having the RT, and the construal level or perception of the RT.

And here I thought RT was always a bad thing...

You can find the full text here.

Watkins ER (2008). Constructive and unconstructive repetitive thought. Psychological bulletin, 134 (2), 163-206 PMID: 18298268

Tuesday, August 18, 2009

Androgen's effects on older female cognitive functioning

Nowadays there seems to be a growing concern for age-related cognitive decline evidenced by the countless number of ads promising brain enhancement through the guise of drugs and nutrients. In addition, studies have shown that female mice exhibit more severe cognitive decline compared to age-matched male mice. So does this mean women should be more vigilant of their brain health and head for the pharmacies before it's too late? Or is all this hoopla just smoke and mirrors?

Saturday, August 15, 2009

Autobiographical and nonautobiographical memory functioning in PTSD

Posttraumatic stress disorder (PTSD) is a debilitating disorder characterized by altered memory functioning including the unintentional reliving of the traumatic experience. This feature of the disorder has been the focus of most PTSD studies, however rarely has there been an investigation on the aspect of disturbed intentional recall within the PTSD patient population.

Jelinek et al. decided to address the paucity in this area of research by first clarifying central qualitative and quantitative aspects of memory functioning in PTSD and then combining prior research on autobiographical and nonautobiographical memory to examine whether memory disorganization of the traumatic event exceeded impairment of verbal memory.

Friday, August 14, 2009

Implicit-memory involved in accurate responding on recognition test

There is a common assumption that accurate recognition exclusively reflects explicit-memory processing. However, Voss and Paller seem to have turned this notion on its head. In their study they found that implicit-memory processes can in fact guide responses in an explicit recognition test.

Kaleidoscope images were used to either divide or keep intact the human subject's attention. These same images were then discriminated from visually similar foils during forced-choice recognition testing.

Do adults with Asperger syndrome really have ToM?

People with autism are known to lack the ability to automatically attribute mental states to self and others also known as "mindblindness". A result of this impairment is failure on verbally instructed false-belief tasks.

However, people with Asperger syndrome, a milder form of autism, seem to pass with flying colors. This presents a problem for the "mindblindness" theory. Do people with Asperger syndrome really have a theory of mind (ToM) contrary to popular theory?

Thursday, August 13, 2009

Early-exposure to a high fat diet shapes future preference

It goes without saying that the US is currently experiencing a rapidly growing obesity epidemic. Researchers from various fields continue to look for possible causes and solutions to such a deleterious medical condition. A recent study conducted by Teegarden, Scott, and Bale seem to have advanced our understanding of obesity just a bit further.

In a 10 day macronutrient choice preference test they found that high fat diet early-exposed mice exhibited a significantly greater preference for a high fat diet later on as adults measured by daily caloric intake. As a control for diet familiarity, mice exposed to a high carbohydrate diet during early life showed no differences in adult macronutrient preferences.

Wednesday, August 12, 2009

The relationship between a leftward bias and negative emotional recognition

There appears to be a growing body of evidence supporting the relationship between space and emotion. For example, a fascinating study by Tamagni, Mantei, and Brugger found that healthy right handed subjects who exhibited a leftward line bisection bias on a lateralized lexical decision task had a recognition advantage for negative over positive emotional words.

The authors suggest that functional hemispheric differences state variables may be less decisive than the trait variable of lateral hemispatial attention and propose a reconsideration of "hemisphericity". Their findings also have complex implications for the interaction between cortical (anterior and posterior)and subcortical structures in the mediation of both the production of emotions and perception.

Tamagni C, Mantei T, & Brugger P (2009). Emotion and space: lateralized emotional word detection depends on line bisection bias. Neuroscience, 162 (4), 1101-5 PMID: 19501133

Tuesday, August 11, 2009

The power of imagination on prejudice

Contact theory seems to be the new hot topic when it comes to solving the age old problem of prejudice. The theory simply states that given the right conditions if members of differing groups come in contact with one another, the interaction ultimately leads to more positive intergroup relations.

Crisp and Turner decided to pose a fascinating question. What if members of those groups didn't actually meet, but simply imagined the positive social interaction? Would the results still be significant? Research has shown that imagining a social situation can have the same effect as the real thing so Crisp and Turner weren't too far off the mark when they decided to persue this line of inquiry.

Monday, August 10, 2009

The negative health effects of perceived discrimination

Discrimination has undoubtedly been the cause of suffering for many throughout human history. There have been countless reviews investigating the effects of discrimination on health, but none that have quite looked at the quantitative nature of this relationship. Pascoe and Richman decided to undertake this task by examining the strength of the evidence for the effect of perceived discrimination on multiple health outcomes through a meta-analysis.

The researchers discovered that an increased level of perceived discrimination is associated with more negative mental and physical health. In addition, they found that perceived discrimination was associated with heightened psychological and physical stress responses as well as increased participation in unhealthy behaviors. These relationships remained even when important covariates such as demographics were analyzed. Moderating variables included social support and coping style.

So the next time you feel like you're being unfairly discriminated against be sure to have lots of family and friends to back you up, think logically through the problem, and take action!

Pascoe EA, & Smart Richman L (2009). Perceived discrimination and health: a meta-analytic review. Psychological bulletin, 135 (4), 531-54 PMID: 19586161

Sunday, August 9, 2009

Chronic stress and its effects on brain plasticity

Stress typically indicates a demand to adapt to challenges found in everyday life. However, when the stress is uncontrollable, unpredictable, and chronic it can increase the brain's vulnerability to disease.

Dagyte et al. over at the University of Groningen investigated the effects of acute and chronic foot-shock stress on neural plasticity by using hippocampal cell proliferation and neurogenesis data collected from rats. They found that repeated, but not acute exposure to foot-shock stress caused a temporary suppression of Ki-67-positive cell proliferation in the dentate gyrus and a reduction in DCX expression.

The authors suggest that a long-term accumulation of the stressors effects on hippocampal cell proliferation may ultimately compromise hippocampal circuitry. So make sure to stay away from chronic stress if you love your hippocampus and all the important things it does for you.

Dagyte G, Van der Zee EA, Postema F, Luiten PG, Den Boer JA, Trentani A, & Meerlo P (2009). Chronic but not acute foot-shock stress leads to temporary suppression of cell proliferation in rat hippocampus. Neuroscience, 162 (4), 904-13 PMID: 19482059

Saturday, August 8, 2009

How gamma oscillations sync the amygdala and striatum during learning

A study conducted by Popescu, Popa, and Pare investigated the underlying mechanism driving amygdalostriatal interactions during memory formation. The impetus for this study came from an interest in studies implicating the basolateral amygdala (BLA) activity in the facilitation of striatal-dependent memories in emotional arousal.

They measured unit and local field potential recordings from the BLA, striatum, auditory cortex, and intralaminar thalamus of cats trained on a stimulus-response task where the presentation of one or two tones predicted reward delivery and found that gamma oscillations originating from the BLA coordinated amygdalostriatal interactions more so than oscillations in other frequency bands. In addition, the coherence of CS-evoked BLA striatial gamma increased along with improvements in behavioral performance during a striatal-dependent stimulus-response task.

The authors suggest that this process may facilitate synaptic plasticity along with other underlying mechanisms.

Popescu AT, Popa D, & Paré D (2009). Coherent gamma oscillations couple the amygdala and striatum during learning. Nature neuroscience PMID: 19430471
Check out Eric Michael Johnson's blog entry over at The Primate Diaries on why chimps make bad suicide bombers. He talks about how spite may be particular to humans while altruism is shared among the animal kingdom.

Friday, August 7, 2009

Hippocampal replay during waking states

Very cool study by Karlsson and Frank showing that rats' reactivate stored representations of remote experiences during waking replay in the hippocampus. But why is it only with remote rather than local replay? They suggest that novel experiences may play a role in which long lasting neuronal excitability and coordination for the cells during those experiences are generated.

In the discussions section they make mention of the probable dysynchronized neocortical state during awake replay constrasted to the synchronized state during sleep replay. They conclude by explaining that awake replay can reactivate a memory of a past experience even during an ongoing experience, potentially creating associations of multiple events across time.

Thursday, August 6, 2009

I feel your pain, but only if we share the same race

An interesting study by Xu et al. over at Peking University has further demonstrated an aspect of evolutionary development that we are trying so hard to escape in the present day world. Racial exclusion, especially when it comes to empathy, can negatively impact our attitudes and behaviors towards outgroups whether we're aware of it or not. Here is their abstract.

The pain matrix including the anterior cingulate cortex (ACC) mediates not only first person pain experience but also empathy for others' pain. It remains unknown, however, whether empathic neural responses of the pain matrix are modulated by racial in-group/out-group relationship. Using functional magnetic resonance imaging we demonstrate that, whereas painful stimulations applied to racial in-group faces induced increased activations in the ACC and inferior frontal/insula cortex in both Caucasians and Chinese, the empathic neural response in the ACC decreased significantly when participants viewed faces of other races. Our findings uncover neural mechanisms of an empathic bias toward racial in-group member.

Hopefully with further studies similar to this one we can come closer to figuring out how to train our seemingly outdated brains to become more tolerant of the "other".

Xu X, Zuo X, Wang X, & Han S (2009). Do you feel my pain? Racial group membership modulates empathic neural responses. The Journal of neuroscience : the official journal of the Society for Neuroscience, 29 (26), 8525-9 PMID: 19571143

Wednesday, August 5, 2009

Amnesic patients with hippocampal damage show recall deficits on the WMT

A recent study by Goodrich-Hunsaker and Hopkins showed that amnesic patients with hippocampal damage performed above the recommended cutoff scores on immediate and delayed recognition of the Word Memory Test (WMT), but were significantly impaired on the multiple-choice, paired associate, and free-recall subtests.

The authors suggest that the hippocampal damage may be the culprit for such impairment. So how do they explain the above cutoff scores on the immediate and delayed recognition subtests? They suggest that the familiarity, simplicity, and repeated presentation of the items may have something to do with it.

A bit of an aside but related to my specific area of interest; I'd bet my meager stipend that if these patients were hooked up to an EEG machine during NREM sleep we'd observe a significant reduction in sleep spindle activity and SWS. Sleep spindles and SWS have been found to be associated with declarative memory consolidation so it'd only seem natural to see such a reduction.

Goodrich-Hunsaker NJ, & Hopkins RO (2009). Word memory test performance in amnesic patients with hippocampal damage. Neuropsychology, 23 (4), 529-34 PMID: 19586216

Tuesday, August 4, 2009

Impairng memory storage, not just retrieval

So THIS is how you really impair memory storage...with an infusion of anisomycin to the dorsal hippocampus! A future PRN for trauma?

Storage or retrieval deficit: The yin and yang of amnesia — Learning & Memory

Monday, August 3, 2009

Quantum mechanics & the brain

Quantum tunneling is where an electron hops from one biomolecule to the next; violating classical laws of physics. Here are a few interesting snippets from Mark Anderson's DISCOVER article Is Quantum Mechanics Controlling Your Brain.

uantum tunneling and smell:
What is really happening, Turin posited, is that the approximately 350 types of human smell receptors perform an act of quantum tunneling when a new odorant enters the nostril and reaches the olfactory nerve. After the odorant attaches to one of the nerve’s receptors, electrons from that receptor tunnel through the odorant, jiggling it back and forth. In this view, the odorant’s unique pattern of vibration is what makes a rose smell rosy and a wet dog smell wet-doggy.

Sunday, August 2, 2009

A new brain snack

Looking for a new brain snack I stumbled upon Ann's House Chocolate Nut Antioxidant at my local Walmart. It's got a blend of cranberries, almonds, and dark chocolate, all ingredients that are healthy for the brain and makes for a tasty mix. It also contains raisins and according to the printed caution, the occasional shell fragment...bon appetit!

Here are some links discussing the benefits of each ingredient:
Dark Chocolate