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D D Simmons

Publications and source records attributed to D D Simmons.

9 recordsLinked to original sources
PubMed1992

Innervation of the amphibian and basilar papillae in the leopard frog: reconstructions of single labeled fibers.

Amphibians have two auditory organs specialized for reception of airborne sounds: the amphibian papilla and the basilar papilla. In this report we examine the morphology of the ganglion cells and the afferent innervation of the sensory epithelium in both auditory organs of the leopard frog, Rana pipiens pipiens. Extracellular injections of either biocytin or horseradish peroxidase (HRP) were made into the VIII nerve; they labeled ganglion cells, their axons, and their terminal fibers within the papillae. Ganglion cells that projected to either the amphibian papilla or basilar papilla had cell bodies that were morphologically distinct from other labeled cells. In the amphibian papilla thick fibers terminated in the rostral portion and thin fibers terminated in the caudal portion. Labeled fibers in the rostral portion traveled short distances before making contacts with up to nine hair cells whereas labeled fibers in the caudal portion traveled longer distances and contacted no more than five hair cells. In the basilar papilla labeled fibers were thick (around 4 microns) and terminated on as many as nine hair cells. Consistent with studies from the bullfrog, Rana catesbeiana, our results suggest that the amphibian papilla of R. pipiens pipiens has a convergent innervation (i.e., multiple hair cells provide input to a single ganglion cell) and is topographically organized. However, in contrast to reports in other ranid species, a highly convergent innervation like that found in the amphibian papilla is also found in the basilar papilla.

Animals↗
PubMed1991

Postnatal maturation of spiral ganglion neurons: a horseradish peroxidase study.

Using an in vitro cochlear preparation from postnatal hamsters, spiral ganglion cells (SGCs) were labeled retrogradely following extracellular injections of HRP into the cochlear nerve. In 24 cochleae from hamsters between postnatal days (P) 0 and 10, the neuronal morphology of 201 SGCs and their peripheral axons were analyzed. From P 0 to 3, labeled SGCs had few distinguishable features. Although SGCs could be traced separately to inner hair cells (IHCs) and outer hair cells (OHCs), they all had roughly bipolar-shaped cell bodies. Approximately half of the labeled SGCs had peripheral axons that spiraled some distance before entering radial fiber bundles. From P 3 to 7, SGCs increased in size by nearly 30% and the number of SGCs with spiraling peripheral axons decreased to near zero. At P 10, the central axon diameter to peripheral axon diameter ratios distinguished two populations of SGCs. The hair-cell innervation patterns of SGCs also changed morphologically as a function of postnatal age. At P 0, radial fiber (RF) terminals of peripheral axons contacted as many as 8 IHCs; by P 3, RFs contacted typically one or two IHCs. The terminal portions of peripheral axons contacting OHCs did not show any appreciable spiral until P 2. By P 5, individual outer spiral fibers (OSFs) had greater spiral lengths underneath row-3 OHCs and the number of OHC contacts was also greatest for row-3 OSFs. These data suggest that SGCs undergo a systematic maturational process. Furthermore, the morphological differentiation of SGCs occurs after they have established separate inner and outer hair cell innervations.

Age Factors↗
PubMed1991

Dietary restraint as values-related motivation: a psychometric clarification.

Psychological motivation toward dietary restraint can be measured by Cognitive Restraint, a subscale on the Three-factor Questionnaire (TFQ; Stunkard & Messick, 1985), and Drive for Thinness, a subscale on the Eating Disorder Inventory (EDI; Garner & Olmstead, 1984). On the basis of data obtained from American undergraduates, these two scales correlated significantly (r = .55); three value scales on the Eating Values Survey (EVS; Simmons, 1989) also correlated significantly with both Cognitive Restraint and Drive for Thinness (Appearance and Manners positively, Enthusiasm negatively). Correlations of other TFQ and EDI scales with values were minimal. Personal values specific to eating are discussed as components of a general motivational orientation toward self-management of eating but as relatively unrelated to such disruptive attributes of eating behavior as disinhibition or bulimia.

Adult↗
PubMed1990

Reconstructions of efferent fibers in the postnatal hamster cochlea.

It is well known that adult-like physiological functioning of the mammalian postnatal cochlea occurs coincidentally with the presence of efferent synapses on outer hair cells (OHCs). This study described the cochlear innervation patterns of thick efferent fibers traveling in the vestibular nerve in postnatal hamsters ranging in age from day zero to day 10. At least three kinds of efferent fibers were labeled via an in vitro horseradish peroxidase (HRP) technique: varicose, thin efferents; nonvaricose, thin efferents; and nonvaricose, thick efferents. Nonvaricose thick efferents were reconstructed from the basal third of the cochlea. Reconstructed efferent fibers traversed in the intraganglionic spiral bundle (IGSB) on the peripheral edge of the spiral ganglion and branched profusely in the osseous spiral lamina (OSL). From day zero to day five, large (greater than 1.0 microns) diameter nonvaricose efferent fibers gave rise to branches that either terminated underneath inner hair cells or appeared to end blindly in the OSL. Efferent fibers also had branches that traveled in the inner spiral bundle (ISB) and tunnel spiral bundle (TSB). In cochleae from hamsters six to eight days old, some thin and thick diameter efferent fibers contacted both inner and outer hair cells. By the tenth day, large diameter fibers traveled radially across the tunnel of Corti to terminate on one to five OHCs. As early as day seven, large diameter fibers also appear to terminate preferentially on OHCs in row one. These observations are consistent with the notion that the end of the first postnatal week represents a critical period in the formation of adult-like synapses on the OHCs. The data also suggest a developmental transition period when efferent fibers contact both hair cell types before contacting OHCs separately.

Animals↗
PubMed1989

Measuring personal values that are specific to eating: reliability, factors, and eating pattern correlates.

Eating disorders, particularly weight control disorders, appear resistant to long-term modification. While personal values have been shown to influence long-term behavior, their influence on eating patterns has not been studied because of the lack of an instrument to measure those values that are specific to eating. The Eating Values Survey (EVS) was created to measure priorities given to 21 eating-related values, such as sensory qualities of food, the experience of hunger, socializing with others, body appearance, nutritional contribution to health, etc. Responses of 109 male and 99 female university students to the EVS were found stable over a 2-week period and revealed five factors, identified as Gusto, Easy Necessity, Orderliness, Gourmet, and Social Approval. EVS scores also correlated significantly with such self-reported eating disorder variables as being overweight and self-induced vomiting. Sex differences in eating values appeared matters of emphasis rather than of distinction.

Adult↗
PubMed1988

Afferent innervation of outer hair cells in adult cats: I. Light microscopic analysis of fibers labeled with horseradish peroxidase.

Outer spiral fibers (OSFs), the afferent innervation of the outer hair cells (OHCs), were retrogradely labeled following horseradish peroxidase injections into the cat's auditory nerve. The peripheral branching patterns of 85 OSFs from adult cochleas were reconstructed. Fibers contacted OHCs via terminal or en passant swellings; however, the latter were seen exclusively in the apical half of the cochlea. Many OSFs also gave off branches ending on structures other than OHCs. Fibers in the cochlear apex were much more highly branched than in the base. Most fibers contacted only one row of OHCs, and more fibers contacted row 1 than row 2 or row 3 OHCs. Third-row fibers were the most highly branched in all cochlear regions. These results are consistent with a growing body of morphological evidence that suggests that the peripheral branching patterns of OSFs may be fundamentally similar in all mammalian ears.

Afferent Pathways↗
PubMed1988

Afferent innervation of outer hair cells in adult cats: II. Electron microscopic analysis of fibers labeled with horseradish peroxidase.

Outer spiral fibers (OSFs) were retrogradely labeled with injections of horseradish peroxidase. After the peripheral arborization patterns were reconstructed at the light microscopic level (Simmons and Liberman, '88), restricted regions of selected fibers were analyzed via electron-microscopic reconstruction of serial sections. The ultrastructural data in the present study suggested that the contact between the outer hair cell (OHC) and the terminal swellings of OSFs corresponds to the afferent synapse described in numerous other ultrastructural studies. The en passant swellings that contacted OHCs also appeared to be points of synaptic contact. However, en passant synapses were not always associated with a swelling of the OSF at the point of contact: thus, the light-microscopic reconstructions probably underestimate the numbers of synapses. OSF branches terminating well below the OHCs were seen to end most commonly in intimate contact with the Deiters' cells. Membrane specialization was occasionally seen at this point of contact; however, the specialization was sufficiently undifferentiated to preclude identification.

Animals↗