Nicotine Linked To Improved Memory Performance

In 2006,  Neuropsychopharmacology published a study with findings of improved memory with the use of nicotine. The “double-blind placebo-controlled study” was conducted on both smoker and non-smoker young adults.  Both groups displayed improved function in memory tasks with nicotine.  In particular, the improved performance in prospective memory occurred when participants devoted their complete attention to the task.  In contrast, when attention was divided, the opposite occurred (see graph below).

There are several contributing factors to this finding.  First, nicotine is a stimulant, so it heightens arousal levels. In cognitive psychology I recently learned that moderately high arousal improves performance on cognitive tasks. I am unsure why nicotine did not improve performance in divided attention. One possible explanation is it is only effective in simple-arousal tasks.  Regardless, this finding shows an aspect of cigarettes in a positive light, a rare event.

So, will people be wearing nicotine patches to in the library in the future? Will we see nicotine pills become the new study aid? Probably not, but this is an interesting concept.  At the very least, this study made me understand why finals week fills the outside perimeter of the library with cigarette smoke.

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Integrating Forensics and Neuroscience

I’ve often wondered what future advancements in neuroscience will bring to criminal justice. The intriguing concept of utilizing neurotechnology for forensic purposes is hot topic these days. Daniel Meegan’s article on neuroimaging techniques for memory detection expands on this notion.  He notes that memory detection techniques provide more accuracy than lie detection techniques according to the theory that an existing memory is detectable regardless of the occurrence of a lie. Memory detection consists of simple measures of neural responses frequently evoked by stimuli. In theory, if a particular stimulus present in the crime scene, brain activity would differ between someone who was not present at the scene and someone who was. Meegan mentions using a Brain fingerprint technique to “exploit the fact that the brain responds differently to sensory stimuli to which is has been exposed before.”  

This is a very new concept in need of development, but it is quite thought provoking and full of attention. What if we could replace the vulnerable, fallible lie detector tests with memory detection? Would this be ethical or an invasion of privacy? 

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Bulimia and the Vagus Nerve

In America, bulimia nervosa is an eating disorder that affects approximately 3% of the female population and up to 6% of females in college. The vast majority of bulimics are female, although there are some male cases. Bulimia nervosa was recognized in 1979 and is currently in the DSM-IV, however treatments are minimal due to lack of understanding about the condition. Around 50% of treated bulimics are helped by pharmaceutical SSRI, in particular Prozac (Fluoxetine), regardless if they display symptoms of depression. What about the other 50%, though?

A study conducted in 2007 by Faris et al provides new insight on this issue. The study’s innovative hypothesis suggests that bulimia is related to a destabilization of the vagus nerve. The vagus nerve (also called cranial nerve ten) affects heart rate, breathing, the larynx, swallowing, and parts of digestion. It is thought that the stimulated vagus nerve is connected to feeding, in particular “meal portion size and feelings of satisfaction after a meal.” Clearly, these attributes hold close ties to bulimia. Their research portrays that bulimics exhibit unusual responses to vagus stimulation in regards to “satiety and emesis, compared to controls (expected after bingeing and purging). Furthermore, bulimics had different responses to “vagal-mediated pain sensitivity,” indicating a below average vagus sensitivity. Ultimately, the researchers offer a model comparing normal linear responses to eating in contrast to the oscillating pattern of response in bulimics.

These neural findings are very important to eating disorder specialists seeking better treatment methods. It is not a cure-all, as bulimia is very complicated and often paired with other emotional disorders (depression, anxiety, etc). However, these findings pave the way for treating the vicious binge-and-purge cycle that causes serious health consequences in the long run.

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Neuroscience and Addiction

Addiction is an issue virtually every society encounters. Clearly, addictive drugs are here to stay, and with the surplus of prescription pills in America, it’s safe to say their numbers are increasing. A recent article by Jeneen Interlandi from the Newsweek Education site provides a detailed work on possible combats to addiction.

According to the article, geneticists have discovered the first gene variants linked to a predisposition to addiction. This is helpful in explaining why only 10% of those who try an addictive drug become addicted. Neuroscientists are trying to incorporate other neural networks; such as taste, sight, and thought, to better determine where trigger areas are located. The study notes of other developments, including vaccines that “trains” the immune system to “block intoxicating effects of drugs.” Another is essentially “willpower-in-a-pill,” stopping addiction impulses.

The article mentions the option of vaccinating “high-risk” teens until their decision-making regions of the brain are fully developed. This clearly raises the a human rights issue on addition to the fact there is no procedure for determining who is “high-risk.” Nonetheless, these developments are a beacon of hope for the many suffering from addiction. But where can we draw the line between personal responsibility and neurological predisposition with these possible advancements?

Deep Brain Stimulation: Another Solution to Epilepsy?

Epilepsy affects one in every 100 people. Fortunately, there are drugs available to control epileptic seizures.  Unfortunately, these drugs only treat approximately 2/3 of the epileptic population. This leaves a significant amount of patients in need of alternative treatment methods.

Enter Deep Brain Stimulation (DBS), a technology already used to treat over 70,000 patients with Parkinson’s disease and other disorders such as epilepsy. Recently, a study was conducted by Stanford’s Kevin D. Graber & Robert S. Fisher on treating epileptic patients with DBS.  The researchers used a device similar to a pacemaker to deliver precise measurements and timed electrical pulses to the brain. Electrodes were placed in the anterior nucleus of the thalamus (where epileptic seizures are commonly triggered). Their population consisted of 110 patients whose seizures were untreatable with drugs and were suffering from an average of 20 seizures per month. Devices were implanted in all participants. For the first 3 months, half of the devices were on and half were off, then both were on for the following 3 months.

Results

3 months

Device 1 on:  40% fewer seizures than before implantation

Device 2 off: 14.5% fewer seizures (placebo effect)

1 Year

Device 1 on: 41%

Device 2 on (9 months): 41%

2 Years

Device 1 & 2: 56%

It is evident this procedure is effective in treating epileptics who are untreatable pharmacologically. However, there are implications and risks involved in the process.  Short-term effects include infection at implantation sight and tingling sensations. The long-term effects are unknown but are not predicted to be particularly damaging. Considering the percentage reduction of seizures after 9 months, this procedure may be worthwhile to many patients.

In March 2010, the FDA approved the usage of DBS for seizure patients untreatable with drugs.

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TMS As A Treatment for Depression

According to the National Institutes of Health, more than 20.9 million adults in the United States, or 9.5% of the population 18 and over, suffer from depression or a related mood disorder (1).  As one of the most prevalent disorders in American society, it is imperative that researchers continue to develop ways to combat depression.  Recently, the utilization of TMS (Transcranial Magnetic Stimulation) on patients with depression proved to be effective.  Over 25 studies on this matter have been conducted internationally, almost all containing results that report TMS improving adult depression (2).

In a study published by the AJP*, Gershon et al reported results in favor of TMS as a valid depression treatment. Their data portrayed an antidepressant effect using high-frequency rTMS, especially when directed towards the left prefrontal cortex (3).  TMS is an appealing tool for the future because it is a relatively short (20-30 min), non-invasive procedure that can be performed on awake patients. To date, the most successful TMS depression treatments prove to be 20-minute procedures, everyday for several weeks (4). Another advantage to TMS is its accuracy, as the technology allows the targeting of very specific regions of the brain while leaving other areas unaffected.

Because TMS is a fairly new form of depression treatment, the long-term lasting effects are still unknown. We know for certain that procedures done correctly yield positive short-term results, but further research is necessary to determine if TMS continues to work after treatment ends.  Everyone knows at least one person who has experienced depression, if one has not experienced it them self.  No one would argue that research devoted to advancing treatments of depression is time well spent.

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ICI Abnormalities in Schizophrenic Patients

Many neuroscientists devote their research to schizophrenia, one of the more debilitating neurological diseases. Recent innovations in neurotechnology (EEG, rTMS, etc), provide researchers with great tools to further examine abnormalities inside the schizophrenic brain. In this particular case I focus on the significant deficits in intracortical inhibition (ICI) in unmedicated patients with schizophrenia.

In a study by Pascual-Leone et al, 14 right-handed schizophrenics, 7 of whom were unmedicated, were compared with 7 right-handed, normal control subjects. The testing used paired-pulse TMS technology. According to the research, the results show that the medicated schizophrenics displayed “5% higher motor thresholds in both hemispheres” in comparison to unmedicated schizophrenics and the control group. The normal control group had an approximately “10% higher threshold for the left than right hemisphere, whereas the opposite was true for the patient groups (5-10% higher threshold on the right than left).” Schizophrenic patients receiving medication displayed considerably decreased ICI in relation to the unmedicated and control groups. Furthermore, this decrease was more distinct in the right hemisphere. The researchers conclude from this study what treatment with “conventional neuroleptics* is associated with increased motor threshold and decreased intracortical inhibition.” Meanwhile, unmedicated patients displayed no difference from normal control group in this realm.  The main conclusion is that schizophrenia may be “characterized by a reversed pattern in interhemispheric corticospinal excitability.”

These findings demonstrate how left-hemisphere abnormality in schizophrenics, specifically in the motor cortex, can be measured through TMS, and thus specific treatment can ensue. Considering the social debilitations schizophrenics suffer from, it is evident that advances in neuro-technology have and will continue to improve the life quality and functionality of those with this disease. Hopefully, these developments will allow for fewer in-patients and institutionalizing of schizophrenics, freeing up needed space and lowering medical costs.

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*Neuroleptic= tranquilizing psychiatric medication used to treat psychosis.