Our lab works on understanding learning and memory sleep/wake circuits and how they are altered in neurological and psychiatric disorders. To achieve these goals, we combine human single neuron recordings from patients, in vivo and slice rodent electrophysiology, optogenetics, multiphoton imaging, and intensive development of new analytical and computational neuroscience tools. We use this careful understanding of circuits to build novel translational therapeutics.

New papers from the lab in 2019:

SPATIAL MEMORY & NAVIGATION

The retrosplenial cortex is an area critical for learning, memory and navigation. Damage to this area leads to pronounced memory impairments and spatial disorientation. This condition has its own name: Retrosplenial Amnesia. However, little is known about the retrosplenial neural code that serves these functions. In this first study, we show that a uniquely excitable cell type in the retrosplenial cortex is ideally suited to encode persistent, precisely timed information, helping to better decipher persistent head-direction input. And watch this space for another, related retrosplenial manuscript.

Brennan EW*, Sudhakar SK*, Jedrasiak-Cape I & Ahmed OJ (2019). Uniquely excitable neurons enable precise and persistent information encoding in the superficial retrosplenial cortex. BioRxiv 673954 preprint; revision invited  [LINK]

A peregrine falcon will reach speeds of 200 miles per hour as it hurtles towards its prey – a pigeon that is itself in full flight as it attempts to escape the looming predator. Despite the speeds involved, the peregrine will still successfully adjust its position to elegantly and precisely intercept its prey. In this review, we synthesize the heavily interconnected neural circuitry that has evolved to integrate speed and space in the brain to make navigational feats such as this possible:

Sheeran WM, Ahmed OJ (2019). The neural circuitry supporting successful spatial navigation despite variable movement speeds. Authorea (May 2) preprint; revision invited   [LINK]  

NEUROLOGICAL DISORDERS

Our computational modeling has identified a new drug combination for treating traumatic brain injuries:

Sudhakar SK, Choi TJ, Ahmed OJ (2019). Biophysical modeling suggests optimal drug combinations for improving the efficacy of GABA agonists after traumatic brain injuries. Journal of Neurotrauma 36(10):1632–1645 [LINK]

Four new commentaries on epilepsy circuits and oscillations:

Sudhakar SK, Ahmed OJ (2019). More is more: potential benefits of characterizing high frequency activity over long durations. Epilepsy Currents 19(6), in press
Brennan EW, Ahmed OJ (2019). Ripple while you walk and you may get lost: pathological high frequency activity can alter spatial navigation circuits. Epilepsy Currents 19(5), in press
Ahmed OJ, Sudhakar SK (2019). High frequency activity during stereotyped low frequency events might help to identify the seizure onset zone. Epilepsy Currents 19(3):184-186 [LINK]
Ahmed OJ, John TT (2019). A straw can break a neural network's back and lead to seizures – but only when delivered at the right time. Epilepsy Currents 19(2):115-116  [LINK]

SLEEP & ADDICTION

Why are only some individuals more likely to relapse after sleep deprivation? Our new manuscript reviews the overlapping neural circuits involved in both sleep-dependent motivation and reward-seeking behaviors. We present evidence in support of the adoption of the Sign-tracking / Goal-tracking preclinical model to better understand how this circuitry linking sleep and addiction differs across individuals:

Ahrens AM, Ahmed OJ (2019). Neural circuits linking sleep and addiction: animal models to understand why select individuals are more vulnerable to substance use disorders after sleep deprivation. Authorea (April 24) preprint; revision invited [LINK]