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Responses to auditory stimuli in macaque lateral intraparietal area

Citation

Linden, Jennifer F. (1999) Responses to auditory stimuli in macaque lateral intraparietal area. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:04092013-145216206

Abstract

The lateral intraparietal area (LIP) of macaque posterior parietal cortex participates in the sensorimotor transformations underlying visually guided eye movements. Area LIP has long been considered unresponsive to auditory stimulation. However, recent studies have shown that neurons in LIP respond to auditory stimuli during an auditory-saccade task, suggesting possible involvement of this area in auditory-to-oculomotor as well as visual-to-oculomotor processing. This dissertation describes investigations which clarify the role of area LIP in auditory-to-oculomotor processing.

Extracellular recordings were obtained from a total of 332 LIP neurons in two macaque monkeys, while the animals performed fixation and saccade tasks involving auditory and visual stimuli. No auditory activity was observed in area LIP before animals were trained to make saccades to auditory stimuli, but responses to auditory stimuli did emerge after auditory-saccade training. Auditory responses in area LIP after auditory-saccade training were significantly stronger in the context of an auditory-saccade task than in the context of a fixation task. Compared to visual responses, auditory responses were also significantly more predictive of movement-related activity in the saccade task. Moreover, while visual responses often had a fast transient component, responses to auditory stimuli in area LIP tended to be gradual in onset and relatively prolonged in duration.

Overall, the analyses demonstrate that responses to auditory stimuli in area LIP are dependent on auditory-saccade training, modulated by behavioral context, and characterized by slow-onset, sustained response profiles. These findings suggest that responses to auditory stimuli are best interpreted as supramodal (cognitive or motor) responses, rather than as modality-specific sensory responses. Auditory responses in area LIP seem to reflect the significance of auditory stimuli as potential targets for eye movements, and may differ from most visual responses in the extent to which they arc abstracted from the sensory parameters of the stimulus.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Computation and Neural Systems
Degree Grantor:California Institute of Technology
Division:Biology
Major Option:Computation and Neural Systems
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Andersen, Richard A.
Thesis Committee:
  • Laurent, Gilles J.
  • Konishi, Mark
  • Perona, Pietro
  • Koch, Christof
  • Fraser, Scott E.
Defense Date:14 May 1999
Record Number:CaltechTHESIS:04092013-145216206
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:04092013-145216206
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7599
Collection:CaltechTHESIS
Deposited By: John Wade
Deposited On:09 Apr 2013 22:40
Last Modified:09 Apr 2013 22:40

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