Figure 1.

Hierarchical clustering analysis of BF neuronal response types. (A) Schematic of the reward-biased simple RT task. Each trial is initiated by a house light signal, prompting rats to enter a nosepoke fixation port. Rats encounter three possibilities while maintaining fixation: (1) S-Large sound predicting 4 drops of water in the adjacent reward port; (2) S-Small sound predicting 1 drop of water; or (3) Catch trials with no sound and no reward. (B) Histological reconstruction of electrode locations. Each color represents the reconstructed recording area from one rat. (C) Hierarchical clustering analysis of all BF neurons based on the similarity of neuronal responses and the associated dendrogram. The clustering algorithm identifies three major types of responses in BF neurons, identified by the same colors in all figure panels: Type-I, red; Type-II, blue; Type-III, green. (D) Three response features from each neuron are used in the hierarchical clustering algorithm, sorted based on neuronal order in the dendrogram. The three features are PSTHs in the [−300, 300]ms window relative to the trial-start light signal, S-Large sound and the Catch stimulus, with baseline firing rates subtracted.