On Thu, 11 Apr 1996, Mark Laubach wrote:
>laubach at biogfx.neuro.wfu.edu (Mark Laubach) wrote:
> >Does anyone know of any recent studies that have examined the cellular
> >basis (i.e., intracellular recordings) of the 20 Hz "somatomotor"
> >rhythm and / or the mu (10-15 Hz) rhythm?
> >Mark Laubach
>> I wanted to clarify this posting.
>> I am interested in any info on thalamic and / or cortical oscillations
> in the ranges of 10-15 and ~20 Hz. I did not find much with medline
> and wondered if there are any electrophysiologists out there who have
> found oscillations in these ranges in the somatosensory, motor, or
> intralaminar nuclei in the thalamus or in sensorimotor areas of
> cortex.
>> Any info would be greatly appreciated.
>> Mark
This may be of interest to you.
On Mon, 6 May 1996, Teresa Binstock wrote:
> Perhaps these will help re: insects and oscillations and olfact...
>> 1
> AU - Laurent G
> AU - Naraghi M
> TI - Odorant-induced oscillations in the mushroom bodies of the locust.
> SO - Journal of Neuroscience 1994 May;14(5 Pt 2):2993-3004
> AB - Kenyon cells are the intrinsic interneurons of the mushroom bodies
> in the insect brain, a center for olfactory and multimodal
> processing and associative learning. These neurons are small (3-8
> microns soma diameter) and numerous (340,000 and 400,000 in the bee
> and cockroach brains, respectively). In Drosophila, Kenyon cells are
> the dominant site of expression of the dunce, DC0, and rutabaga gene
> products, enzymes in the cAMP cascade whose absence leads to
> specific defects in olfactory learning. In honeybees, the volume of
> the mushroom body neurophils may depend on the age or social status
> of the individual. Although the anatomy of these neurons has been
> known for nearly a century, their physiological properties and the
> principles of information processing in the circuits that they form
> are totally unknown. This article provides a first such
> characterization. The activity of Kenyon cells was recorded in vivo
> from locust brains with intracellular and local field potential
> electrodes during olfactory processing. Kenyon cells had a high
> input impedance (approximately 1 G omega at the soma). They produced
> action potentials upon depolarization, and consistently showed spike
> adaptation during long depolarizing current pulses. They generally
> displayed a low resting level of spike activity in the absence of
> sensory stimulation, despite a large background of spontaneous
> synaptic activity, and showed no intrinsic bursting behavior.
> Presentation of an airborne odor, but not air alone, to an antenna
> evoked spatially coherent field potential oscillations in the
> ipsilateral mushroom body, with a frequency of approximately 20 Hz.
I believe the 20 hertz is a carrier wave. Low frequency carrier waves in
electronic have a greater range in transmission. So 20 hertz is a carrier
wave for olifaction. The high frequency osscilations are the actual
processing of the olifactory chemical. This should be gaussian and the
real identification should be able to be calculated. By tuning in advance
the nervous system to 20 hertz by entrainment the basic signal for a odor
may be deduced from the background signal. My believe is due to a global theory
of correlational opponent-processing. Ron Blue
> The frequency of these oscillations was independent of the nature of
> the odorant. Short bouts of oscillations sometimes occurred
> spontaneously, that is, in the absence of odorant stimulation.
> Autocorrelograms of the local field potentials in the absence of
> olfactory stimulation revealed small peaks at +/- 50 msec,
> suggesting an intrinsic tendency of the mushroom body networks to
> oscillate at 20 Hz. Such oscillatory behavior could not be seen from
> local field potential recordings in the antennal lobes, and may thus
> be generated in the mushroom body, or via feedback interactions with
> downstream neurons in the protocerebrum. During the odor-induced
> oscillations, the membrane potential of Kenyon cells oscillated
> around the resting level, under the influence of excitatory inputs
> phase-locked to the field activity. Each phasic wave of
> depolarization in a Kenyon cell could be amplified by intrinsic
> excitable properties of the dendritic membrane, and sometimes led to
> one action potential, whose timing was phase-locked to the
> population oscillations.(ABSTRACT TRUNCATED AT 400 WORDS)
>> 2
> AU - Kirschfeld K
> TI - Oscillations in the insect brain: do they correspond to the cortical
> gamma-waves of vertebrates?.
> SO - Proceedings of the National Academy of Sciences of the United States of
> America 1992 May 15;89(10):4764-8
> AB - gamma-waves, relatively high-frequency oscillations (30-80 Hz) that
> can be recorded in the olfactory system and the visual cortex of
> vertebrates, have recently attracted much attention. A role as an
> information carrier is under discussion, a possible involvement in
> "feature linking" has been suggested, and they have also been
> implicated functionally in phenomena such as mind consciousness or
> awareness. It has long been known that stimulus-dependent
> high-frequency oscillations (hf waves) can also be recorded from the
> optic lobes of arthropods. These oscillations in flies have been
> examined and found to be analogous to the gamma-waves in many
> respects. Based on knowledge of the anatomy and physiology of the
> visual system in flies, the most plausible interpretation of the
> function of these oscillations differs from the interpretations of
> the vertebrate gamma-waves currently under consideration.
>>>>