Evolution in Nervous Systems

Figure 1: The evolving literature on the default mode network (DMN). Since the publication of “A Default Mode of Brain Function” (Raichle et al. 2001), nearly 3,000 papers have been published on this ...

Figure 2: Views of the default mode network from the perspective of activity decreases during task performance (a) and resting-state functional connectivity (b and c), and in relation to other network...

Figure 3: Comparison of the default mode network (DMN) in rat, monkey, and human. For the rat DMN (a, top panel): significant clusters include 1, orbital cortex; 2, prelimbic cortex (PrL); 3, cingulat...

Figure 1: Elements of a simple decision between two alternatives. The left side represents elements of the world. The right side represents elements of the decision process in the brain. Black element...

Figure 2: Sequential analysis. (a) General framework. The decision is based on a sequence of observations. After each acquisition, a DV is calculated from the evidence obtained up to that point; then ...

Figure 3: Neural correlates of a decision about vibrotactile frquency. (a) Testing paradigm. A test probe delivers a sinusoidal tactile stimulus to the finger at base frequency f1. After a delay perio...

Figure 4: Representation of an evolving DV by the motor system. (a) Interrupted direction discrimination task. The monkey decides the net direction of motion, here shown as up versus down. Task diffic...

Figure 5: Neural mechanism of a decision about direction of motion. (a) Choice-reaction time (RT) version of the direction discrimination task. The subject views a patch of dynamic random dots and dec...

Figure 6: Effects of microstimulation in MT and LIP. In both areas microstimulation (red curves) causes a change in both choice and RT. The schematic shows the consequences of adding a small change in...

Figure 7: Motion detection. (a) Detection task. The monkey views a RDM stimulus without any net direction of motion and must release a bar when the motion becomes coherent. Task difficulty is controll...

Figure 8: Vibrotactile detection. (a) Task. The VTF probe is placed on the finger pad. After a random delay, a 20-Hz sinusoidal indentation is applied on half the trials. The monkey must decide whethe...

Figure 9: A simple model for “go” reaction times. (a) The LATER model. Instead of accumulating random draws of momentary evidence, the DV is a ramp with a slope drawn from a Gaussian distribution. The...

Figure 1: Schematic diagram of some of the extrinsic and intrinsic connections of the prefrontal cortex. The partial convergence of inputs from many brain systems and internal connections of the pref...

Figure 2: Schematic diagram illustrating our suggested role for the PF cortex in cognitive control. Shown are processing units representing cues such as sensory inputs, current motivational state, me...

Figure 3: (A) Shown is the activity of four single prefrontal (PF) neurons when each of two objects, on different trials, instructed either a saccade to the right or a saccade to the left. The lines ...

Figure 4: Schematic of the Stroop model. Circles represent processing units, corresponding to a population of neurons assumed to code a given piece of information. Lines represent connections between...

Figure 5: Time course of fMRI activity in dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) during two phases of a trial in the instructed Stroop task. During the instruction...

Figure 1: Zebrafish is an ideal species to study the neurobiological basis of natural behavior. This is made possible by a combination of techniques, including new developments in animal tracking, mat...

Figure 2: Behavioral tracking, from individual posture to group dynamics. (a) Larval fish swimming in shallow water observed from above with a high-speed camera. (b) Automated image processing is used...

Figure 3: Illustrations of some larval behaviors. (a) Phototaxis using spatial and temporal cues. Larvae can stay in a small illuminated area by turning away from a light-dark boundary (left). They ca...

Figure 4: Adult and juvenile behaviors. (a) Freely moving groups of four-week-old zebrafish show strong schooling behavior. (b) Two-choice setup with transparent divider used to show attraction of thr...

Figure 1: Example dynamics and population state of a frictionless pendulum. (a–c) A pendulum is a 2D dynamical system that has a simple relationship between the changes of the state of the pendulum (1...

Figure 2: Neural population state and neural dynamics. (a) Three neurons spike through time (left), and these spikes are binned and counted (center). These spike counts are plotted in a three-dimensio...

Figure 3: Linear dynamics and linear approximations of nonlinear systems around fixed points. (a–g) Examples of linearized dynamics around fixed points in a nonlinear system, showing fixed points (lar...

Figure 4: Contextual inputs. A static or slowly varying input can be viewed as contextualizing a nonlinear system such that it produces different dynamics under different values of the contextual inpu...

Figure 5: Subspaces and manifolds. (a) Two-dimensional (2D) linear subspace (blue) embedded in a three-dimensional (3D) space. (b) One-dimensional (1D) ring manifold (green) embedded in 3D space. (c) ...

Figure 6: Null and potent subspaces. A state space can be divided up into nonoverlapping subspaces, called the potent and null (sub)spaces, where the potent space may be read out by a downstream area,...