Crossroads Newsletter July 2006

Effect of neurofeedback training on the neural substrates of selective attention in children with attention-deficit/hyperactivity disorder: A functional magnetic resonance imaging study
February 2006

Attention Deficit Hyperactivity Disorder (AD/HD) is a neurodevelopmental disorder mainly characterized by impairments in cognitive functions. Functional neuroimaging studies carried out in individuals with AD/HD have shown abnormal functioning of the anterior cingulate cortex (ACC) during tasks involving selective attention.

In other respects, there is mounting evidence that neurofeedback training (NFT) can significantly improve cognitive functioning in AD/HD children. In this context, the present functional magnetic resonance imaging (fMRI) study was conducted to measure the effect of NFT on the neural substrates of selective attention in children with AD/HD.
(abstract)

Abnormal Brain Anatomy in Children with ADHD

(Nov. 29, 2004) CHICAGO -

Children with attention deficit hyperactivity disorder (ADHD) display anatomical brain abnormalities beyond chemical imbalance, according to research presented at the annual meeting of the Radiological Society of North America (RSNA).

"We found abnormality of the fiber pathways in the frontal cortex, basal ganglia, brain stem and cerebellum," said lead author of both studies, Manzar Ashtari, PhD., associate professor of radiology and psychiatry at North Shore-Long Island Jewish Health System in New Hyde Park, N.Y.

"These areas are involved in the processes that regulate attention, impulsive behavior, motor activity, and inhibition-the key symptoms in ADHD children." Dr. Ashtari said. "They are also known to be part of a bigger circuit in the brain that establishes communication between the frontal lobe and cerebellum."

Using diffusion tensor imaging (DTI) to compare 18 children with diagnosed ADHD with 15 control children to evaluate the brain's white-matter fiber development, Dr. Ashtari's team found differences in the brain fiber pathways that transmit and receive information among brain areas. "Typically ADHD is described as a chemical imbalance, but our research has shown that there may also be subtle anatomical differences in areas of the brain that are important in this disorder."
(more)

Cerebellum in attention-deficit hyperactivity disorder: a morphometric MRI study

Neurology 1998
American Academy of Neurology

Clinical, neuroanatomic, neurobehavioral, and functional brainimaging studies suggest a role for the cerebellum in cognitive functions, including attention. However, the cerebellum has not been systematically studied in attention-deficit hyperactivity disorder (ADHD).

We quantified the cerebellar and vermal volumes, and the midsagittal areas of three vermal regions, from MRIs of 46 righthanded boys with ADHD and 47 matched healthy controls. Vermal volume was significantly less in the boys with ADHD. This reduction involved mainly the posterior inferior lobe (lobules VIII to X) but not the posterior superior lobe (lobules VI to VII).

These results remained significant even after adjustment for brain volume and IQ. A cerebello- thalamo-prefrontal circuit dysfunction may subserve the motor control, inhibition, and executive function deficits encountered in ADHD.
(abstract)

NEUROLOGY OF EMOTION AND COGNITION
1997

The term emotion, like all other perceptions, refers to subjective feeling state that is essentially a private experience. As such, emotions and related experiential states cannot be studied or measured directly but may be inferred through observable and sometimes quantifiable behaviors called indicators.

Emotional indicators include behaviors that are organized through the endocrine, visceral and somatic nervous systems that may induce changes in heart rate, breathing, capillary circulation, sweating, lacrimation, pupillary size, endocrine secretion and sphincter control, freezing, flight or fight, arousal, and species-specific vocalizations and emotional displays. In humans, language may also serve as an indicator through both the verbal and prosodic aspects of communication.

More importantly, researchers have posited for decades that cognition (knowledge acquired by the animal through life experiences) is also an integral part of the emotional process.
(complete review)

NutraSweet (Aspartame) Shown to Cause Cancer
March 2006

The final report of a seven-year study on aspartame (also known as Nutra-Sweet or Equal) has linked it to high rates of lymphomas, leukemias, and other cancers in rats.

The rats were given the equivalent of four to five bottles of diet soda a day for a human. The carcinogenic effect of aspartame was found at levels as low as 400 parts per million, or about 20 milligrams a day for humans. This is far less than current daily limits in America (50 milligrams) and the UK (40 milligrams).

When the initial findings were released almost a year ago, they were met with criticism from artificial sweetener trade groups, and support from groups critical of aspartame.

No government regulatory agency has yet acted on the findings; there have been calls for a ban in Britain, and the European Food Safety Authority has begun a review of the study's results. United States FDA officials have said that they also intend to conduct a review.
(complete story)

Lead exposure through gestation-only caused long-term learning/memory deficits in young adult offspring

Abstract:

Numerous observations in clinical and preclinical studies indicate that the developing brain is particular sensitive to lead (Pb)’s effects.

However, the effect of gestation-only Pb exposure on cognitive functions at maturation has not been studied. We investigated the potential effects of three levels of Pb exposure (low, middle, and high Pb: 0.03%, 0.09%, and 0.27% of lead acetatecontaining diets) at the gestational period on the spatial memory of young adult offspring by Morris water maze spatial learning and fixed location/visible platform tasks.

Our results revealed that three levels of Pb exposure significantly impaired memory retrieval in male offspring, but only female offspring at low levels of Pb exposure showed impairment of memory retrieval. These impairments were not due to the gross disturbances in motor performance and in vision because these animals performed the fixed location/visible platform task as well as controls, indicating that the specific aspects of spatial learning/memory were impaired. These results suggest that exposure to Pb during the gestational period is sufficient to cause long-term learning/memory deficits in young adult offspring.
(complete article)

Call to Congress To Ban Prescription Drug Ads To Consumers

May 2006

Thirty-nine medical, health and seniors' organizations are urging Congress to stop the advertising of prescription drugs to consumers.

As Robert A. Schoellhorn, former chairman of Abbott Laboratories warned more than two decades ago, "We believe direct advertising to the consumer introduces a very real possibility of causing harm to patients who may respond to advertisements by pressuring physicians to prescribe medications that may not be required."

The groups are now seeking Members of Congress to introduce legislation in the U.S. Senate and House of(DTC) prescription drug ads.
(complete story)

Neuroimaging in drug and substance abuse part II: opioids and solvents.

Top Magn Reson Imaging. 2005 Jun;16(3):239-45.
Borne J, Riascos R, Cuellar H, Vargas D, Rojas R.
Neuroradiology Section, Louisiana State University
The central nervous system is one of the primary targets for the detrimental effects of drugs of abuse. Diagnostic imaging, especially MRI, plays an important role in the detection of complications associated with drug abuse.

We present the imaging findings associated with the abuse of opioids and other morphine derivatives, as well, as solvents. Of the morphine derivatives, heroin is the most commonly abused. Several CNS pathologic effects have been described in association with its abuse. These include neurovascular complications such as microvascular ischemic changes or ischemic stroke.

A rare form of leukoencephalopathy has been described in those abusers who inhale heroin vapors. Other neurologic complications include atrophy and various infectious processes. Solvent inhalation is a common practice among adolescents and young adults secondary to its ease of access and low cost.

The most important component of industrial solvents is toluene. Complications of toluene abuse may be either acute, showing no neuroradiological changes, or chronic, characterized by cerebral and cerebellar demyelination as well as atrophy.