LIP has been the area for studying motion direction discrimination as model of decision-making.  In this paper, Katz et al show that deactivation of LIP has little effect on that model task.  Deactivating an upstream area, MT, where decision signals are weaker, however, caused a big deficit.

Dissociated functional significance of decision-related activity in the primate dorsal stream.  Leor N. Katz, Jacob L. Yates, Jonathan W. Pillow & Alexander C. Huk  Nature.

Sure, this is a cautionary tale of correlates does not equal causation.  But it is important not to over-interpret the results of lesions/deactivations.  They identify *bottlenecks* in neural processing, not contributions.  Just because there is no effect of deactivation doesn’t mean that a given area doesn’t contribute.  MT could be providing the raw materials that a number of downstream areas, including LIP, use for decision-making.   This doesn’t mean that LIP doesn’t contribute to decisions, it just means that it is not the only area that contributes.

This is in line with recent work showing that neural processing is more distributed than previously thought.  For example, see:
Siegel, M., Buschman, T.J., and Miller, E.K. (2015) Cortical information flow during flexible sensorimotor decisions.  Science. 19 June 2015: 1352-1355. View PDF »




About the Author

The Miller Lab uses experimental and theoretical approaches to study the neural basis of the high-level cognitive functions that underlie complex goal-directed behavior.