Posts classified under: Integrative Center for Learning and Memory

Ausaf Bari, MA, M.D., Ph.D., FAANS

Dr. Bari specializes in the neurosurgical repair and restoration of brain and nerve function. Following his neurosurgery residency training at UCLA, Dr. Bari was awarded the prestigious William P. Van Wagenen Fellowship to train at the world-renowned functional neurosurgery program at the University of Toronto. He has extensive clinical and research experience in the use of deep brain stimulation (DBS) in the treatment of both movement and psychiatric disorders. Dr. Bari’s clinical practice includes DBS surgery for Parkinson’s disease, tremor, dystonia, depression and OCD. In addition, his clinical practice includes neurosurgery for brain tumors, pain, and peripheral nerve disorders.

Dr. Bari’s research focuses on an interdisciplinary approach to studying the neurobiology underlying movement and psychiatric disorders and expanding the frontiers of neurosurgery to treat those disorders. As a part of his fellowship training, Dr. Bari studied the relationship between the motor and reward systems of the brain and the use of deep brain stimulation to modify and enhance them. A native of California, Dr. Bari completed his neurosurgery residency training at UCLA after receiving his MD and PhD degrees from Boston University. He completed his undergraduate training at UC Berkeley in the field of neurobiology.

David Clewett, Ph.D.

Research and Teaching Interests:

In everyday life, we encounter a continuous stream of information. Yet, because our mental resources are limited, we cannot process and remember everything we experience. This raises two critical questions: How do we prioritize and store important information in memory? How do unfolding experiences become organized into memories of meaningful events? My research examines the brain mechanisms that support these adaptive memory processes.

A key theoretical construct motivating my work is that physiological arousal plays a fundamental role in facilitating attention and memory. Decades of research show that people perceive and remember emotionally arousing events better than more mundane events. For example, experiencing a car crash or celebrating a birthday tend to be more memorable than a routine commute to work. Beyond simply enhancing processing of the emotional information, however, a surge in arousal can also spillover to enhance or impair processing of nearby neutral information. Spikes in arousal are also happening all the time and not just in response to emotional events. Consequently, even as everyday experiences unfold, arousal states may play a lead role in determining whether an event will be forgotten or etched into memory more permanently.

My research seeks to understand how arousal responses – particularly those elicited by emotional, stressful or motivating (rewarding/threatening) situations – influence: (1) what we remember: the information we selectively attend to and remember later on; (2) how we remember: the way in which memories become organized and updated over time; and (3) when we remember: certain neurochemical and brain states, such as elevated norepinephrine and dopamine release, that are induced before, during or after an event. To study these topics, my lab takes a multi-modal approach that includes functional and structural neuroimaging (fMRI/MRI/DTI), neurophysiology (eye tracking and hormone assays), pharmacology, and behavioral methods.


David Clewett will join UCLA as an Assistant Professor of Psychology in July 2020. He received his PhD in Neuroscience from the University of Southern California in 2016, where he worked with Dr. Mara Mather to study emotion-cognition interactions. He then conducted a postdoctoral fellowship with Dr. Lila Davachi at NYU and Columbia University, where he studied how episodic memories are constructed from continuous experience. Before attending graduate school, he received a B.S. degree in Biopsychology with a minor in English from the University of California, Santa Barbara.


  • Clewett, D.* & Murty, V.* (in press). Echoes of emotions past: How neuromodulators determine what we recollect. ENeuro. *authors contributed equally
  • Clewett, D., Dubrow, S., & Davachi, L. (2019). Transcending time in the brain: How event memories emerge from experience. Hippocampus, 29(3), 162-183.
  • Clewett, D., Huang, R., Velasco, R., Lee, T.H., & Mather, M. (2018). Locus coeruleus activity strengthens prioritized memories under arousal. Journal of Neuroscience, 38(6), 1558-1574.
  • Clewett, D., & Davachi, L. (2017). The ebb and flow of experience determines the temporal structure of memory. Current Opinion in Behavioral Sciences, 17, 186-193.
  • Clewett, D., Sakaki, M., Huang, R., Nielsen, S., & Mather, M. (2017). Arousal amplifies biased competition between high and low priority memories more in women than in men: the role of elevated noradrenergic activity. Psychoneuroendocrinology, 80, 80-91.
  • Clewett, D., Sakaki, M., Nielsen, S., Petzinger, G., & Mather, M. (2017). Noradrenergic mechanisms of arousal’s bidirectional effects on episodic memory. Neurobiology of Learning and Memory137, 1-14.
  • Mather, M., Clewett, D., Sakaki, M., & Harley, C. (2015). Norepinephrine ignites local hot spots of neuronal excitation: How arousal amplifies selectivity in perception and memory. Behavioral and Brain Sciences, 1-100.

Avishek Adhikari, Ph.D.


Dr. Adhikari joined UCLA’s Psychology Department in 2016, following postdoctoral training at Stanford University with Prof. Karl Deisseroth and Ph.D. studies at Columbia University with Prof. Joshua A. Gordon and Prof. Rene Hen.

Dr. Adhikari’s lab investigates how the brain coordinates the constellation of changes related to emotional behaviors, with a focus on fear and anxiety. These multi-faceted changes involve complex and dynamic adaptations in hormonal, physiological and behavioral realms. Dr. Adhikari dissects how interactions between different brain structures control these processes, seeking insights that shed light on the neural basis of pathological anxiety disorders and adaptive aversion to danger. To do so we use a combination of powerful techniques, including electrophysiology, behavioral assays, optogenetics and calcium imaging to monitor and control neural activity and behavior.

Learn more about our research at our lab website


A selected list of publications:

Ye Li, Allen William E, Thompson Kimberly R, Tian Qiyuan, Hsueh Brian, Ramakrishnan Charu, Wang Ai-Chi, Jennings Joshua H, Adhikari Avishek, Halpern Casey H, Witten Ilana B, Barth Alison L, Luo Liqun, McNab Jennifer A, Deisseroth Karl   Wiring and Molecular Features of Prefrontal Ensembles Representing Distinct Experiences Cell, 2016; 165(7): 1776-88.
Adhikari Avishek, Lerner Talia N, Finkelstein Joel, Pak Sally, Jennings Joshua H, Davidson Thomas J, Ferenczi Emily, Gunaydin Lisa A, Mirzabekov Julie J, Ye Li, Kim Sung-Yon, Lei Anna, Deisseroth Karl   Basomedial amygdala mediates top-down control of anxiety and fear Nature, 2015; 527(7577): 179-85.
Adhikari Avishek   Distributed circuits underlying anxiety Frontiers in behavioral neuroscience, 2014; 8(7): 112.
Gunaydin Lisa A, Grosenick Logan, Finkelstein Joel C, Kauvar Isaac V, Fenno Lief E, Adhikari Avishek, Lammel Stephan, Mirzabekov Julie J, Airan Raag D, Zalocusky Kelly A, Tye Kay M, Anikeeva Polina, Malenka Robert C, Deisseroth Karl   Natural neural projection dynamics underlying social behavior Cell, 2014; 157(7): 1535-51.
Kim Sung-Yon, Adhikari Avishek, Lee Soo Yeun, Marshel James H, Kim Christina K, Mallory Caitlin S, Lo Maisie, Pak Sally, Mattis Joanna, Lim Byung Kook, Malenka Robert C, Warden Melissa R, Neve Rachael, Tye Kay M, Deisseroth Karl   Diverging neural pathways assemble a behavioural state from separable features in anxiety Nature, 2013; 496(7444): 219-23.
Tye Kay M, Mirzabekov Julie J, Warden Melissa R, Ferenczi Emily A, Tsai Hsing-Chen, Finkelstein Joel, Kim Sung-Yon, Adhikari Avishek, Thompson Kimberly R, Andalman Aaron S, Gunaydin Lisa A, Witten Ilana B, Deisseroth Karl   Dopamine neurons modulate neural encoding and expression of depression-related behaviour Nature, 2013; 493(7433): 537-41.
Warden Melissa R, Selimbeyoglu Aslihan, Mirzabekov Julie J, Lo Maisie, Thompson Kimberly R, Kim Sung-Yon, Adhikari Avishek, Tye Kay M, Frank Loren M, Deisseroth Karl   A prefrontal cortex-brainstem neuronal projection that controls response to behavioural challenge Nature, 2012; 492(7429): 428-32.
Nason Malcolm W, Adhikari Avishek, Bozinoski Marjan, Gordon Joshua A, Role Lorna W   Disrupted activity in the hippocampal-accumbens circuit of type III neuregulin 1 mutant mice Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 2011; 36(2): 488-96.
Adhikari Avishek, Sigurdsson Torfi, Topiwala Mihir A, Gordon Joshua A   Cross-correlation of instantaneous amplitudes of field potential oscillations: a straightforward method to estimate the directionality and lag between brain areas Journal of neuroscience methods, 2010; 191(2): 191-200.
Resende Rodrigo R, da Costa José L, Kihara Alexandre H, Adhikari Avishek, Lorençon Eudes   Intracellular Ca2+ regulation during neuronal differentiation of murine embryonal carcinoma and mesenchymal stem cells Stem cells and development, 2010; 19(3): 379-94.
Adhikari Avishek, Topiwala Mihir A, Gordon Joshua A   Synchronized activity between the ventral hippocampus and the medial prefrontal cortex during anxiety Neuron, 2010; 65(2): 257-69.
Resende Rodrigo R, Adhikari Avishek   Cholinergic receptor pathways involved in apoptosis, cell proliferation and neuronal differentiation Cell communication and signaling : CCS, 2009; 7(2): 20.
Resende Rodrigo R, Gomes Katia N, Adhikari Avishek, Britto Luiz R G, Ulrich Henning   Mechanism of acetylcholine-induced calcium signaling during neuronal differentiation of P19 embryonal carcinoma cells in vitro Cell calcium, 2008; 43(2): 107-21.
Bechara Etelvino J H, Dutra Fernando, Cardoso Vanessa E S, Sartori Adriano, Olympio Kelly P K, Penatti Carlos A A, Adhikari Avishek, Assunção Nilson A   The dual face of endogenous alpha-aminoketones: pro-oxidizing metabolic weapons Comparative biochemistry and physiology. Toxicology & pharmacology : CBP, 2008; 146(1-2): 88-110.
Adhikari Avishek, Penatti Carlos A A, Resende Rodrigo R, Ulrich Henning, Britto Luiz R G, Bechara Etelvino J H   5-Aminolevulinate and 4, 5-dioxovalerate ions decrease GABA(A) receptor density in neuronal cells, synaptosomes and rat brain Brain research, 2006; 1093(1): 95-104.