Question

1. Conversion of stimulus energy into a signal which can be conveyed to the central nervous system is called coding. Describe how the following relationships (between characteristics of sensory units and characteristics of stimuli) influence primary sensory coding and subsequent afferent input to the CNS. Modality - Receptive field overlap Stimulus intensity - Recruitment Stimulus location-Labeled Lines Acuity-Receptive field size, Receptive field density, Convergence Make sure to demonstrate understanding of involved concepts/important related terms in order to get full credit- describing the above relationships without adequate background information will not be enough.

Answer 1

Ans: sensory input has different steps and each relationship has its own influence or importance in the process:

Sensory coding: - Typing of inf processing that occur in nervous system Have following steps: - Reception: - Specialized sensory receptors absorb physical energy from sensory stimuli Transduction: - Physical energy rightarrow Electrical energy by neuronal firing. Coding: - Correspondence b/w specific parameters of stimulus & specific parameters of neuronal firing that represent it. Awareness: Possible conscious perception of encoded. Sensory stimuli. Effect of various Relationships: Modality - Receptive field Overlap: - Receptive field overlap: - Receptive field of sensory neuron is particular region of sensory space in which a stimulus will modify firing of neuron. eg hair, piece al skin so the reception of stimulus at receptive field cause modulation of neuron firing rate Reception field have central firing) & concentric rings (firing) so the fields overlap to modify receptor field at other cells \r\n Stimulus intensity - Recruitment: - When there is increase in no. of as primary afferent fibres responding. The selection at fibres are to intensity is called recruitment.