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Biomedical subjects

P Grigg

Publications and source records attributed to P Grigg.

45 records · Page 3Linked to original sources
PubMed1977

Response of primate joint afferent neurons to mechanical stimulation of knee joint.

1. One hundred thirty-eight knee joint afferents from posterior articular nerve (PAN), in primates, were recorded in dorsal root filaments. Responses of afferents were studied in relation to both passive manipulations of the knee and active contractions of quadriceps, semimembranosus, and gastrocnemius muscles. 2. When the knee was passively rotated, most neurons discharged only when extreme angular displacements were achieved. Response of neurons responding to passive extensions was linearly related to the torque applied to the knee. With maintained extensions, discharge in extension neurons adapted slowly. Some of the time constants of adaptation were similar to those for simultaneously recorded torque relaxation. 3. Contractions of quadriceps, semimembranosus, or gastrocnemius muscles could activate many neurons in the absence of changes in joint angle. For quadriceps-activated neurons, rather high torques (mean = 2,450 g with cm) were required. 4. The results support the hypothesis that joint afferents function as capsullar stretch receptors, responding to those mechanical events which result in loading of the capsule.

Adaptation, Physiological↗
PubMed1975

Spatial and chromatic properties of neurons subserving foveal and parafoveal vision in rhesus monkey.

The response properties of neurons in the region of striate cortex subserving central retina (0 degrees-2 degrees) and in a region of representation of parafoveal retina (4 degrees-7 degrees) were studied in unanesthetized paralyzed macaque monkeys. Neurons sensitive to the orientation of the stimulus in the visual field (simple, complex, and hypercomplex), and neurons lacking orientation selectivity (concentric, and a new class termed uniform) were found. In foveal cortex non-oriented cells were more numerous, and orientation sensitive cells had less strict spatial stimulus requirements than in parafoveal cortex. Most neurons received a monocular input, either exclusively or very predominantly. Three types of neurons were recognized on the basis of their responses to chromatic stimuli. (1) Luminosity neurons (about half the population) gave the same qualitative response to all effective wayelengths and had a spectral sensitivity similar to that of the macaque, determined behaviorally. Cells with all spatial types of receptive fields, except simple, occurred in this group. (2) Spectrally-treated neurons also responded in the same manner to different wavelengths, but over a narrower range than luminosity neurons, and their maximal sensitivity was shifted toward one or the other end of the visible spectrum. All tuned neurons had uniform or complex receptive field. (3) Spectrally-opponent neurons were either excited or inhibited by long wavelengths and responded in the opposite manner to short wavelengths. For cells with uniform or complex receptive fields the two opponent systems were coextensive. Simple or concentric neurons often had dual-opponent organization. The distribution of functional types among different cortical layers was similar in parafoveal and foveal cortex. The functional attributes of ocular dominance and orientation sensitivity were found to be statistically independent dimensions of cortical organization. On the other hand, the correlation between spatial and chromatic properties did not vary between different cytoarchitectonic layers, a finding suggesting that these neuronal properties depend on conjoined projectional and intracortical connecting mechanisms.

Animals↗
PubMed1975

Mechanical factors influencing response of joint afferent neurons from cat knee.

The responses of 67 slowly adapting joint afferent neurons in cat posterior articular nerve (PAN) were studied in relation to mechanical stimulation of the knee. The response of most neurons could be interpreted in terms of the stretching of joint tissues resulting from angular displacement of the knee. No neurons discharged at angles intermediate between the limits of movement of the joint. The limits of movement of the joint were operationally defined in terms of displacements resulting from applied torques.

Animals↗
PubMedDate not supplied

Computer-assisted learning in dentistry. A view from the UK.

OBJECTIVES: The objectives of this paper are to review the development and impact of computer assisted learning (CAL) in dentistry with emphasis on the UK. DATA SOURCES: This is a wide ranging review of dental, medical and technical literature. STUDY SELECTION: An attempt has been made to evaluate present knowledge in an objective manner and to make some prediction as to the future development and use of computer-based teaching methods in dentistry. CONCLUSIONS: The introduction of computers as an educational tool in dentistry and the provision of CAL is having an impact not only on how dentists are trained but also on the skills they will need to acquire in the future to keep pace with this new technology. It is suggested that there is a great potential for computer-based continuing professional education for dental practitioners, and that the Internet will provide access to such material.

Computer Communication Networks↗
PubMedDate not supplied

The evaluation of three computer-assisted learning packages for general dental practitioners.

Two studies were undertaken to determine the acceptability of computer-assisted learning (CAL) to general dental practitioners. The first was a single programme in two parts designed to give experience in orthodontic cases assessment and treatment planning, developed at the Bristol Dental School. The second contained two modules, one on the planning and management of dental biopsy and the other on surgical endodontics, developed within the Leeds Dental Institute. An identical self-administered questionnaire was completed by participants in the evaluation study. Knowledge and skill gains were indicated following study of the modules. The modules were also found to be easy to use and useful. The CAL approach was rated positively compared to audio tapes, books and journals, but a less consistent pictures when CAL was compared with videotapes. The study provides evidence for the acceptability and potential of the CAL approach to general dental practitioners.

Attitude to Computers↗