Cognitive and Neural Bases of Skilled Performance
Abstract
Major improvements were introduced for neuromagnetic studies by the installation of a magnetically shielded room and versatile gantry to hold our 5- sensor neuromagnetometer. Studies with this system verify that the strength of the 100-ms component of the cortical response to a tone is unaffected by tone frequency and intensity at suprathreshold levels, but we have shown that both the 100-ms and 180-ms components are affected by attention. Moreover, we have obtained evidence that auditory cortex in left and right hemispheres may have differing responses to a tone depending on the inter-stimulus interval. Neuronal sources of certain components of auditory-evoked responses are found to be displaced across cortex from the others, with a tonotopic representation for the 50-ms transient component apparently differing from the representation for the steady-state component, which has a similar apparent latency. Studies of spatial attention have revealed robust effects for latencies exceeding 200 ms, unlike for the auditory system, but some subjects show effects commencing as early as 100 ms. An investigation of the classic P300 response for both visual and auditory stimulation has been initiated with a more efficient paradigm, and early results provide evidence that the neuronal source is independent of sensory modality. To address the question of how much cortex is involved in producing an evoked field or potential, we have analyzed published data on intracortical voltage measurements in cat and monkey and found that the current dipole moment per square millimeter of cortical area is very much the same at moments of peak activity for long-latency responses. (SDW)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 09, 1990
- Accession Number
- ADA226668
Entities
People
- Lloyd Kaufman
- Samuel J. Williamson
Organizations
- New York University