Richard Marrocco

Professor, Department of Psychology,
Institute of Cognitive and Decision Sciences

B.A., 1965, University of California, Los Angeles
Ph.D., 1971, University of Indiana

Research Interests

Neurobiology of visual attention; pharmacology of arousal and attention

Email
Marrocco Lab

The focus of our research is to understand the mechanisms that underlie attention in primates and humans. We are currently interested in the role of the noradrenergic (NE) and cholinergic (ACh) neurotransmitter systems in shifting attention in the visual field. We have trained monkeys to perform tasks in which they pay attention to locations in space while fixating a visual target. The locations are signaled by visual cues, which alert the animal that subsequent targets will soon appear at that location. Thus, the cues provide both temporal and spatial information. Drugs that selectively lower brain NE levels exclusively impair utilization of the temporal information, while those that alter ACh levels solely affect attention shifting. Our results suggest that NE may facilitate cholinergically based attentional movements.

Our recent work attempts to localize the structures in the brain that mediate shifts of attention. We have made local infusions of cholinergic antagonists into the intraparietal cortex and into surrounding areas while the animals performed the task. The results for the intraparietal infusions but not other areas have shown a temporary impairment of attention shifting that is similar to those seen after systemic injections of the same drug. These data strongly suggest that cholinergic circuits within the parietal cortex are critical for normal visuospatial attentional function.

Selected Publications (more publications)

B.G.. Oberlin, J.A. Alford, and R.T. Marrocco. (2005) Normal attention orienting but abnormal stimulus alerting and conflict in combined subtype of ADHD. Behav Brain Res, 165 (1): 1-11.

Beane M, Marrocco RT. (2004) Norepinephrine and acetylcholine mediation of the components of reflexive attention: implications for attention deficit disorders. Prog Neurobiol. 74 (3): 167-81.

Shirtcliff EA, Marrocco RT (2003) Salivary cotinine levels in human tobacco smokers predict the attentional validity effect size during smoking abstinence. Psychopharmacology, 166 (1): 11-8.

Cutrell EB, Marrocco RT. (2002) Electrical microstimulation of primate posterior parietal cortex initiates orienting and alerting components of covert attention. Exp Brain Res. 144 (1): 103-13.

Cutrell, E.B. and Marrocco, R.T. (2002) Electrical microstimulation of primate posterior parietal cortex initiates orienting and alerting components of covert attention. Exp. Brain Res. 144(1): 103-113.

Bushnell, P.J., Levin, E.D., Marrocco, R.T., Sarter, M.F., Strupp, B.J., and Warburton, D.M. (2000) Attention as a target of intoxication: insights and methods from studies of drug abuse. Neurotoxicol. Teratol. 22(4):487-502.

Davidson, M.C. and Marrocco, R.T. (2000) Local infusion of scopolamine into lateral intraparietal cortex alters covert orienting in rhesus monkeys. J. Neurophysiol. 83:1536-1549.

Spezio, M.L., Keller, C.H., Marrocco, R.T., and Takahashi, T.T. (2000) Head-related transfer functions of the Rhesus monkey. Hear. Res. 144(144): 73-88.

Davidson, M.C., Cutrell, E.B., and Marrocco, R.T. (1999) Scopolamine slows the orienting of attention in primates to cued visual targets. Psychopharmacology 142(1): 1-8.

Marrocco, R.T. and Davidson, M.C. (1998) The Neurochemistry of Attention. In Parasuraman, R. (ed) The Attentive Brain. MIT Press: Cambridge, MA.

Witte, E.A., and Marrocco, R.T. (1997) Effects of altering brain cholinergic activity on covert orienting of attention: comparison of monkey and human performance. Psvchopharmacology 132: 324-334.

Witte, E.A. and Marrocco, R.T. (1997) Alteration of brain catecholamine levels in Rhesus monkeys affects the alerting component of covert orienting. Psychopharmacology 132: 315-323.

Marrocco, R.T., McClurkin, J.W., and Alkire, M.T. (1996) The influence of the visual cortex on the spatiotemporal response properties of lateral geniculate nucleus cells. Brain Res. 737(1-2):110-118.

Witte, E.A., Villareal, M., and Marrocco, R.T. (1997) Visual orienting and alerting in rhesus monkeys: comparison with humans. Behav. Brain Res. 82 (1): 103-112.

Marrocco, R.T., Witte, E., and Davidson, M.C. (1994) Arousal systems. Curr. Opin. Neurobiol. 4: 166-170.

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