TB10 B&B Lecture 2; How can multiple neurons represent information? 0.0 / 5 ? PsychologyTB10 B&BUniversityNone Created by: mint75Created on: 23-05-16 12:57 How can the ambiguity in single neuron bell curves be resolved? Adding another neuron, different patterns seen at each stimulus value 1 of 20 What is coarse coding? Each neuron represents a range of possible input values 2 of 20 What can be used to decode the value signalled from coarse coding? A firing rate weighted average of each neurons preferred value 3 of 20 Which is the correct way to work out a firing rate weighted average? (Sum of) Firing rate x preferred firing/total amount of firing 4 of 20 Population codes...? Resolve ambiguity present in the firing of individual neurons 5 of 20 Which is the best known population code? Retinal code for colour 6 of 20 What is the name for a pattern that cant be distinguished aka a indistinguishable percept? Metamers, mixtures that produce the same activity. Cant be distinguished from spectral colours 7 of 20 What is a metamer? Mixtures that produce the same activity as a spectral colour 8 of 20 What is a spectral colour? Colours that correspond to a single wavelength 9 of 20 Does the brain work by DECODING or RECODING? Recoding 10 of 20 What is sparsity? The proportion of neurons that fire in a given time window 11 of 20 What is breadth of tuning in relation to sparsity? The proportion of stimuli to which a given neuron responds 12 of 20 Which allow for rapid learning and allow for simple network architecture? Sparse population codes 13 of 20 Which is more likely to exist in the brain? Sparse/dense population codes 14 of 20 What are two dimensions through which shape can be represented? Curvature and outline 15 of 20 Shape representations in V4...? Show feature-based population coding 16 of 20 The preferred value/firing rate of V4 neurons... Varies systematically with the shape and orientation of simple silhouettes 17 of 20 What was the task in a study by Georgopoulous et al? The monkey moves the lever from the centre to a direction along 360 degree of points. 18 of 20 What was found in a study by Georgopoulous et al? Activity increases when lever is about to be moved in the preferred direction 19 of 20 How can you calculate a weighted average of directional measures as in Georgopoulous et al? Vector sum of prefered directions weighted by firing rate. Population vector predicts actual movement 20 of 20
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