Re: Coherent brain frequency measurement (?)

[Eugene Lyskov <eugene.lyskov@NIWL.SE>]

Visual steady-state evoked potentials can be recorded at frequencies higher
than critical fusion frequency, up to 60 and in a some cases 70 Hz. Some
persons have secondary peak at CFF (somewhat about 40 Hz!!). See: Regan D.
(1989). Human Brain Electrophysiology. Evoked potentials and Evoked magnetic
fields in Science and Medicine. Elsevier. NY
We recorded VEPs in conditions of direct viewing of video display with
refresh rate 60 Hz. (Paper will be published in International Journal of
Psychophysiology.


Eugene Lyskov, PhD, MD.

At 13.12 1998-03-12 +1100, you wrote:
>There are visual steady-state evoked potentials with a peak response around
>16 stimuli per second (similar frequency to the maximum photo-convulsive
>sensitivity). "Evoked Potentials in Clinical Medicine" by Chiappa has a
>short section on steady-state stimulation with references to what is now
>quite a large literature.
>
>David Tomkins, Senior Scientist
>Clinical Neurophysiology
>Royal Melbourne Hospital
>Melbourne, Australia 3050
>Tel: +61 3 9342 7583, Fax: +61 3 9342 7272
>
>> ----------
>> From:         Jerry Larson[SMTP:jerry@NEUROMON.COM]
>> Reply To:     Professional discussions of neurophysiology
>> Sent:         Wednesday, 11 March 1998 1:13PM
>> To:   Multiple recipients of list CLIN_NEUROPHYSIOL
>> Subject:      Re: Coherent brain frequency measurement (?)
>>
>> >I have been very interested in a technique described in the following
>> paper
>> >for determining a nonlinear 'resonance' in the human brain's response to
>> >auditory stimulation (usually around 40 Hz for awake, unanesthetized
>> human
>> >subjects):
>> >
>> >Sapsford DJ. Pickworth AJ. Jones JG. A method for producing the coherent
>> >frequency: a steady-state auditory
>> >evoked response in the electroencephalogram. [Journal Article] Anesthesia
>> &
>> >Analgesia. 83(6):1273-8, 1996 Dec.
>>
>> Since the middle latency potentials are linked to state of consciousness,
>> it makes sense to try to use them to assess levels of anesthesia. but I
>> don't see that it has anything to do with the brain having a "resonance"
>> at
>> 40 Hz.  ......  Also, if
>> it really has to do with a resonant frequency characteristic of the brain,
>> why are there not 40Hz visual and somatosensory potentials?
>>
>>
>
>