Limits...
Planning activity for internally generated reward goals in monkey amygdala neurons.

Hernádi I, Grabenhorst F, Schultz W - Nat. Neurosci. (2015)

Bottom Line: The best rewards are often distant and can only be achieved by planning and decision-making over several steps.Such prospective activity could underlie the formation and pursuit of internal plans characteristic of goal-directed behavior.The existence of neuronal planning activity in the amygdala suggests that this structure is important in guiding behavior toward internally generated, distant goals.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.

ABSTRACT
The best rewards are often distant and can only be achieved by planning and decision-making over several steps. We designed a multi-step choice task in which monkeys followed internal plans to save rewards toward self-defined goals. During this self-controlled behavior, amygdala neurons showed future-oriented activity that reflected the animal's plan to obtain specific rewards several trials ahead. This prospective activity encoded crucial components of the animal's plan, including value and length of the planned choice sequence. It began on initial trials when a plan would be formed, reappeared step by step until reward receipt, and readily updated with a new sequence. It predicted performance, including errors, and typically disappeared during instructed behavior. Such prospective activity could underlie the formation and pursuit of internal plans characteristic of goal-directed behavior. The existence of neuronal planning activity in the amygdala suggests that this structure is important in guiding behavior toward internally generated, distant goals.

Show MeSH

Related in: MedlinePlus

Different forms of planning activity in four single amygdala neurons. (a) Activity of this neuron, as in Fig. 2, reflected sequence value across all trials. Right panel: regression betas obtained by fitting Eq. 6 to neuronal activity. (b) Activity of this neuron at trial start before fixation (“Pre-fix period”) reflected sequence value specifically on the first trial of each sequence (bold colors), but not on subsequent trials (light colors). Right panel: regression betas obtained by fitting Eq. 8 to neuronal activity. First trial indicator: indicator variable for the first trial in a saving sequence. First trial indicator × sequence value: regressor for testing sequence value coding specifically on first saving trials. (Statistics for first-trial effects were based on data from all save trials including bold and light colored data. The linear regression in the middle panel remained significant when the effect of outliers was reduced using robust regression.) (c) Activity of this neuron during the fixation and cue periods reflected final sequence length, rather than sequence value, across all saving trials. Activity was higher for shorter sequences. Right panel: regression betas obtained by fitting Eq. 7 to neuronal activity. (d) Activity of this neuron in the fixation period reflected sequence length specifically on first saving trials. Right panel: regression betas obtained by fitting Eq. 9 to neuronal activity. First trial indicator × sequence length: regressor for testing sequence length coding specifically on first saving trials.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4340753&req=5

Figure 3: Different forms of planning activity in four single amygdala neurons. (a) Activity of this neuron, as in Fig. 2, reflected sequence value across all trials. Right panel: regression betas obtained by fitting Eq. 6 to neuronal activity. (b) Activity of this neuron at trial start before fixation (“Pre-fix period”) reflected sequence value specifically on the first trial of each sequence (bold colors), but not on subsequent trials (light colors). Right panel: regression betas obtained by fitting Eq. 8 to neuronal activity. First trial indicator: indicator variable for the first trial in a saving sequence. First trial indicator × sequence value: regressor for testing sequence value coding specifically on first saving trials. (Statistics for first-trial effects were based on data from all save trials including bold and light colored data. The linear regression in the middle panel remained significant when the effect of outliers was reduced using robust regression.) (c) Activity of this neuron during the fixation and cue periods reflected final sequence length, rather than sequence value, across all saving trials. Activity was higher for shorter sequences. Right panel: regression betas obtained by fitting Eq. 7 to neuronal activity. (d) Activity of this neuron in the fixation period reflected sequence length specifically on first saving trials. Right panel: regression betas obtained by fitting Eq. 9 to neuronal activity. First trial indicator × sequence length: regressor for testing sequence length coding specifically on first saving trials.

Mentions: We found different forms of planning activity as illustrated in Fig. 3 for four single amygdala neurons. The neuron in Fig. 3a resembled the one in Fig. 2 as it signaled sequence value across all trials (P = 0.04, n = 53, multiple regression). In addition, it encoded spend values on single trials (Fig. 3aright). To be engaged in planned saving, amygdala neurons should also encode the initial setting of a plan, which may occur as early as the first trial of a sequence. This is exactly what we observed for the neuron in Fig. 3b. This neuron encoded sequence value specifically on the first trial of each sequence (Fig. 3a,b, bold colors) but not on subsequent trials (light colors). In this neuron, planning activity occurred early on at trial start before fixation. Multiple regression confirmed a parametric value signal (P = 5.9 × 10−4, n = 42, Fig. 3b right), which differed distinctly from categorical coding of sequence onset previously found in amygdala neurons during an instructed task33. Accordingly, this neuron encoded the prospective valuation of an internal saving plan, well before the animal implemented the plan.


Planning activity for internally generated reward goals in monkey amygdala neurons.

Hernádi I, Grabenhorst F, Schultz W - Nat. Neurosci. (2015)

Different forms of planning activity in four single amygdala neurons. (a) Activity of this neuron, as in Fig. 2, reflected sequence value across all trials. Right panel: regression betas obtained by fitting Eq. 6 to neuronal activity. (b) Activity of this neuron at trial start before fixation (“Pre-fix period”) reflected sequence value specifically on the first trial of each sequence (bold colors), but not on subsequent trials (light colors). Right panel: regression betas obtained by fitting Eq. 8 to neuronal activity. First trial indicator: indicator variable for the first trial in a saving sequence. First trial indicator × sequence value: regressor for testing sequence value coding specifically on first saving trials. (Statistics for first-trial effects were based on data from all save trials including bold and light colored data. The linear regression in the middle panel remained significant when the effect of outliers was reduced using robust regression.) (c) Activity of this neuron during the fixation and cue periods reflected final sequence length, rather than sequence value, across all saving trials. Activity was higher for shorter sequences. Right panel: regression betas obtained by fitting Eq. 7 to neuronal activity. (d) Activity of this neuron in the fixation period reflected sequence length specifically on first saving trials. Right panel: regression betas obtained by fitting Eq. 9 to neuronal activity. First trial indicator × sequence length: regressor for testing sequence length coding specifically on first saving trials.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4340753&req=5

Figure 3: Different forms of planning activity in four single amygdala neurons. (a) Activity of this neuron, as in Fig. 2, reflected sequence value across all trials. Right panel: regression betas obtained by fitting Eq. 6 to neuronal activity. (b) Activity of this neuron at trial start before fixation (“Pre-fix period”) reflected sequence value specifically on the first trial of each sequence (bold colors), but not on subsequent trials (light colors). Right panel: regression betas obtained by fitting Eq. 8 to neuronal activity. First trial indicator: indicator variable for the first trial in a saving sequence. First trial indicator × sequence value: regressor for testing sequence value coding specifically on first saving trials. (Statistics for first-trial effects were based on data from all save trials including bold and light colored data. The linear regression in the middle panel remained significant when the effect of outliers was reduced using robust regression.) (c) Activity of this neuron during the fixation and cue periods reflected final sequence length, rather than sequence value, across all saving trials. Activity was higher for shorter sequences. Right panel: regression betas obtained by fitting Eq. 7 to neuronal activity. (d) Activity of this neuron in the fixation period reflected sequence length specifically on first saving trials. Right panel: regression betas obtained by fitting Eq. 9 to neuronal activity. First trial indicator × sequence length: regressor for testing sequence length coding specifically on first saving trials.
Mentions: We found different forms of planning activity as illustrated in Fig. 3 for four single amygdala neurons. The neuron in Fig. 3a resembled the one in Fig. 2 as it signaled sequence value across all trials (P = 0.04, n = 53, multiple regression). In addition, it encoded spend values on single trials (Fig. 3aright). To be engaged in planned saving, amygdala neurons should also encode the initial setting of a plan, which may occur as early as the first trial of a sequence. This is exactly what we observed for the neuron in Fig. 3b. This neuron encoded sequence value specifically on the first trial of each sequence (Fig. 3a,b, bold colors) but not on subsequent trials (light colors). In this neuron, planning activity occurred early on at trial start before fixation. Multiple regression confirmed a parametric value signal (P = 5.9 × 10−4, n = 42, Fig. 3b right), which differed distinctly from categorical coding of sequence onset previously found in amygdala neurons during an instructed task33. Accordingly, this neuron encoded the prospective valuation of an internal saving plan, well before the animal implemented the plan.

Bottom Line: The best rewards are often distant and can only be achieved by planning and decision-making over several steps.Such prospective activity could underlie the formation and pursuit of internal plans characteristic of goal-directed behavior.The existence of neuronal planning activity in the amygdala suggests that this structure is important in guiding behavior toward internally generated, distant goals.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.

ABSTRACT
The best rewards are often distant and can only be achieved by planning and decision-making over several steps. We designed a multi-step choice task in which monkeys followed internal plans to save rewards toward self-defined goals. During this self-controlled behavior, amygdala neurons showed future-oriented activity that reflected the animal's plan to obtain specific rewards several trials ahead. This prospective activity encoded crucial components of the animal's plan, including value and length of the planned choice sequence. It began on initial trials when a plan would be formed, reappeared step by step until reward receipt, and readily updated with a new sequence. It predicted performance, including errors, and typically disappeared during instructed behavior. Such prospective activity could underlie the formation and pursuit of internal plans characteristic of goal-directed behavior. The existence of neuronal planning activity in the amygdala suggests that this structure is important in guiding behavior toward internally generated, distant goals.

Show MeSH
Related in: MedlinePlus