Inner-ear disorders may be key to ADHD

Behavioral abnormalities are traditionally thought to originate in the brain, but researchers at the Albert Einstein College of Medicine have found that inner-ear dysfunction can directly cause neurological disorders such as hyperactivity. Their intriguing study, published inScience, implicates two brain proteins that could be targets for novel interventions.

“Our study provides the first evidence that a sensory impairment, such as inner-ear dysfunction, can induce specific molecular changes in the brain that cause maladaptive behaviors traditionally considered to originate exclusively in the brain,” said study leader Jean M. Hébert (pictured).

The idea for the study arose when co-researcher Michelle W. Antoine noticed that some mice in the laboratory were unusually active – in a state of near-continual movement, chasing their tails in a circular pattern. Further investigation revealed that the mice had severe cochlear (responsible for hearing) and vestibular defects (responsible for balance) and were profoundly deaf. “We then realized that these mice provided a good opportunity to study the relationship between inner-ear dysfunction and behavior,” said Hébert.

The researchers established that the animals’ inner-ear problems were due to a mutation in a gene called Slc12a2, which mediates the transport of sodium, potassium, and chloride molecules in various tissues, including the inner ear and central nervous system. The gene is also found in humans.

To determine whether the gene mutation was linked to the animals’ hyperactivity, the researchers took healthy mice and selectively deleted Slc12a2 from either the inner ear, various parts of the brain that control movement or the entire central nervous system. “To our surprise, it was only when we deleted the gene from the inner ear that we observed increased locomotor activity,” said Hébert.

The researchers hypothesized that inner-ear defects cause abnormal functioning of the striatum, a central brain area that controls movement. Tests revealed increased levels of two proteins involved in a signaling pathway that controls the action of neurotransmitters: pERK (phosphorylated extracellular signal-regulated kinase) and pCREB (phospho-cAMP response-element binding protein), which is further down the signaling pathway from pERK. Increases in levels of the two proteins were seen only in the striatum and not in other forebrain regions.

To discover whether increased pERK levels caused the abnormal increase in locomotor activity, Slc12a2-deficient mice were given injections of SL327, a pERK inhibitor. Administering SL327 restored locomotor activity to normal, without affecting activity levels in controls. The SL327 injections did not affect grooming, suggesting that increased pERK in the striatum selectively elevates locomotor activity and not general activity.

According to the researchers, the findings suggest that hyperactivity in children with inner-ear disorders might be controllable with medications that directly or indirectly inhibit the pERK pathway in the striatum. “Our study also raises the intriguing possibility that other sensory impairments not associated with inner-ear defects could cause or contribute to psychiatric or motor disorders that are now considered exclusively of cerebral origin,” said Hébert. “This is an area that has not been well studied.”

Related:
Discuss this article in our forum
Medicos mull possible link between obesity and ADHD
Striking correlation found between infection and mood disorders
Scientists merge electronics with bio-printed ear

Source: Albert Einstein College of Medicine

, ,

Comments are closed.

 Material : Solid Steel Inner Diameter : Front to back 9

Material : Solid Steel Inner Diameter : Front to back 9" Ear to Ear : 8" Circ

$86.00



Vtg Rudolf Schick Publishing Inner Ear 35 x 43 Inch Hanging School Wall Poster picture

Vtg Rudolf Schick Publishing Inner Ear 35 x 43 Inch Hanging School Wall Poster

$16.98



Littlest Pet Shop LPS 401 Kitty Cat Yellow Pink Inner Ear Green Dot Eyes picture

Littlest Pet Shop LPS 401 Kitty Cat Yellow Pink Inner Ear Green Dot Eyes

$8.98



Walt Disney World Parks Inside Out Anger Headband Light Up NWOT Plastic Ears picture

Walt Disney World Parks Inside Out Anger Headband Light Up NWOT Plastic Ears

$19.99



Cetacean Inner Ear Bone (Tympanic Bulla) Fossil – ca. 15 Million Years Old picture

Cetacean Inner Ear Bone (Tympanic Bulla) Fossil – ca. 15 Million Years Old

$12.00



Massive Inner Ear Bone Fossil Tusk  Megalodon Site Found in Morgan River  picture

Massive Inner Ear Bone Fossil Tusk  Megalodon Site Found in Morgan River

$75.00



RIYIN21 Hearing Aids for Seniors & Adults,Inner-Ear Digital Red  picture

RIYIN21 Hearing Aids for Seniors & Adults,Inner-Ear Digital Red

$62.81



Whale Inner Ear Bone Fossilized Whale Bulla Fossil South Carolina 3

Whale Inner Ear Bone Fossilized Whale Bulla Fossil South Carolina 3" 3.9 oz.

$29.87



Marlin Spike Adventurer's Treasure Combo: Unleash Your Inner Explorer picture

Marlin Spike Adventurer's Treasure Combo: Unleash Your Inner Explorer

$99.00



🦄Disney Store Exclusive Dumbo Gray Elephant w/Silky Pink Inner Ears 8” Plush picture

🦄Disney Store Exclusive Dumbo Gray Elephant w/Silky Pink Inner Ears 8” Plush

$75.00



Powered by WordPress. Designed by WooThemes