Optimal resolution in intrinsic optical imaging of barrel responses in the rat somatosensory cortex

s202

OPTIMAL RESOLUTION IN INTRINSIC OPTICAL IMAGING OF BARREL RESPONSES THE RAT SOMATOSENSORY CORTEX.

406

ITARU YAZAWA,

KATSUSHIGE

SATO, TOSHIHISA

TANAKA, YOKO MOMOSE-SATO,

KOHTARO

IN

KAMINO

Dept. Physiol., Tokyo. Med. & Dent. Univ. Sch. Med., Tokyo 113-8519, Japan Image analysis techniques were used to examine intrinsic optical changes m W~star rat barrel responses that occurred dunng somatosensory

cortex actlvlty evoked by mechanical movement of the Dl whisker.

barrel responses 605,750,

First, we tried to detect intrinsic opt&

through the skull and through the dura, and we were able to Image the response at incident wavelengths

of

and 8.50 nm. However, the spatial resolution of the image through the skull appeared to be limited by light-

scattering in the bone: the boundary of the image seemed to be blurred. evoked optical signal Increased with repetitive stlmulatlon, examine the relationship obtained the followmg

Second, m the image through the dura, the size of the

suggesting the summation of the response.

Third, we tried to

between the barrel response and the depth of focus, using an optlcal sectioning method, and we have results: m the postnatal 3 week-old rat, the image of the response area was constant when the depth of

focus was varied from the surface of the cortex to a depth of 500 pm, and in the postnatal 4 week- or 5 week-old rat, the image of the response had its maximum extent at a depth of 500 l.trn. VARIABILITY AND REGULARITY IN THE NEURAL RESPONSES TO WHISKER MONITORED OPTICALLY IN A SINGLE CORTICAL BARREL OFTHE RAT.

407 TOSHIHISA

TANAKA,

Dept. Physiol.,

KATSUSHIGE

SATO, ITARU YAZAWA, YOKO MOMOSE-SATO,

Tokyo. Med. & Dent. Univ. Sch. Med., Tokyo 1138519,

KOHTARO

KAMINO

Japan

We used optical imaging of intrinsic signals to examine the spatto-temporal

patterning of the cortical barrel response in

postnatal Wistar rats from 2 to 7 weeks. Barrel responses were evoked by Dl-whisker intnnsic optlcal signals and images were obtained from the somatosensory of the barrel response area decreased gradually as postnatal development

MOVEMENTS

movement

stimulation,

and the

cortex through the dura mater. The averaged size proceeded from 2 weeks to 7 weeks of age. On the

other hand, m a single cortical barrel, the size and orientation of the response areas varied across the trials and developmental ages with the same whisker stimulation. have introduced

In order to clarify the charactenstics

of the variablhty in the barrel-response

areas, we

Index, k=SRi12, in which SR is the size of the response area, and 1 is the perimeter of the

a dimensionless

response area, and we compared the values of k among the trials. We have found that k IS approximately

0.07 for every trial.

This result suggests that a prmciple of “slmllarity” holds m the trial-to-trial variations m the response area.

408

CORTICAL CONNECTIONS

OF THE PRIMARY SOMATOSENSORY

CORTEX AND CORTICAL

TASTE AREA IN RATS

TOM10 HAYAMA & HISASHI Dept. of Physiol.,

Kumamoto

OGAWA

University

We examined cortical connections

School of Medicine, Kumamoto,

of the primary somatosensory

tract tracing method using WGA-HRP.

860-0811

cortex (SI) and the cortical taste area (CTA) in rats with a

When the tracer was injected in a portion(s) within SI, we found labeled cell bodies

and/or axon terminals in five regions outside SI in the ipsilateral cortex: two rostra1 to SI and three lateral to SI corresponding to the possible two motor areas, SII, PV (Parietal ventral area) and PR (Parietal rhinal area) (Fabri & Burton, 190 1).

In the

contralateral cortex, quite sparse labels were found in SI and other areas except jaw regions in SI where we found dense homotopical

callosal connections.

terminals in a rostrocaudally

When injected in a portion within CTA, we ipsilaterally saw labeled cell bodies and/or

elongated portion including the injection site: denser labels were recognized

the possible two motor areas, a site neighboring dense labels were found in the site homotopical

caudally to the injection site, SII, PV and PR.

in six regions.

to the injection site while sparse labels were seen in other sites.

showed that the SI and CTA have a similar ipsilateral cortical connections

i.e.,

In the contralateral cortex

but quite different contralateral ones,

The results