The relationship of age and hypertension with cognition and gray matter cerebral blood volume in a rhesus monkey model of human aging.
The goal of this study was to investigate whether alterations in cerebral microvasculature, as measured by cerebral blood volume (CBV), contribute to age- and hypertension-related impairments in cognitive function with a focus on executive function and memory. Data were collected on 19 male rhesus monkeys ranging from 6.4 to 21.6 years of age. Hypertension was induced through surgical coarctation of the thoracic aorta. We assessed whether performance on tasks of memory and executive function corresponded to CBV in either the hippocampus or prefrontal cortex. We found a relationship between duration of hypertension and CBV ...
Source: Behavioral Neuroscience - July 1, 2021 Category: Neuroscience Source Type: research
Aversive outcomes impact human olfactory discrimination learning and generalization.
Learning associations between sensory stimuli and outcomes, and generalizing these associations to novel stimuli, are a fundamental feature of adaptive behavior. Given a noisy olfactory world, stimulus generalization holds unique relevance for the olfactory system. Recent studies suggest that aversive outcomes induce wider generalization curves by modulating discrimination thresholds, but evidence for similar processes in olfaction does not exist. Here, we use a novel olfactory discrimination learning paradigm to address the question of how outcome valence impacts associative learning and generalization in humans. Subjects...
Source: Behavioral Neuroscience - July 1, 2021 Category: Neuroscience Source Type: research
Role of dorsal hippocampal muscarinic receptor activity in acquisition and retention of single- versus multiple-trial contextual fear conditioning in adolescent rats.
The present study examined the effects of the muscarinic acetylcholine receptor (mAChR) antagonist, scopolamine, on standard contextual fear conditioning (sCFC). It compared effects of the drug on acquisition (post-shock freezing) versus 24-hr retention of a context-shock association acquired after one or three pairings of a context with unsignaled shock. During single-trial sCFC, systemic scopolamine (0.5 mg/kg, i.p.) prior to training abolished both post-shock and retention freezing (Experiment 1). This same injection during multiple-trial sCFC also abolished post-shock freezing and impaired 24-hr retention freezing (Exp...
Source: Behavioral Neuroscience - June 24, 2021 Category: Neuroscience Source Type: research
Prospective representations in rat orbitofrontal ensembles.
This study demonstrates a behaviorally relevant predictive code in rat OFC. (PsycInfo Database Record (c) 2021 APA, all rights reserved) (Source: Behavioral Neuroscience)
Source: Behavioral Neuroscience - June 24, 2021 Category: Neuroscience Source Type: research
Certainty and uncertainty of the future changes planning and sunk costs.
Many foraging experiments have found that subjects are suboptimal in foraging tasks, waiting out delays longer than they should given the reward structure of the environment. Additionally, theories of decision-making suggest that actions arise from interactions between multiple decision-making systems and that these systems should depend on the availability of information about the future. To explore suboptimal behavior on foraging tasks and how varying the amount of future information changed behavior, we ran rats on two matching neuroeconomic foraging tasks, Known Delay (KD) and Randomized Delay (RD), with the only diffe...
Source: Behavioral Neuroscience - June 24, 2021 Category: Neuroscience Source Type: research
Beyond olfaction: Beneficial effects of olfactory training extend to aging-related cognitive decline.
Studies on olfactory training (OT) outcomes have mostly been limited to olfactory performance, while direct neural connections between olfactory system and amygdala–hippocampal complex allow expecting OT to have psychological effects. To address this hypothesis, we examined olfactory, cognitive and emotional effects of OT in the group of 68 subjects aged between 50 and 88 years (Mage = 62.8 ± 8.9 years; 28 males) who are likely to experience an age-related decline in olfactory and cognitive performance. We diversified stimuli used in the OT to verify whether odor mixtures result in more effective activation of olfactory...
Source: Behavioral Neuroscience - June 10, 2021 Category: Neuroscience Source Type: research
Hesperetin rescues emotional memory and synaptic plasticity deficit in aged rats.
Emotional memory deficit is often accompanied by Alzheimer’s disease and normal aging. It is important to do what is possible to alleviate or rescue emotional memory deficit in aging to improve the quality of older adults. Hesperetin is a flavonoid and an aglycone of hesperidin, it easily passes through the blood–brain barrier into the brain and exerts neuroprotective effects. However, little is known about its neuroprotective effect on emotional memory in aging. To address this issue, we examined the role of hesperetin in the regulation of hippocampal long-term potentiation (LTP), surface expression of α-amino-3-hydr...
Source: Behavioral Neuroscience - June 7, 2021 Category: Neuroscience Source Type: research
A reminder before extinction failed to prevent the return of conditioned threat responses irrespective of threat memory intensity in rats.
After retrieval, reactivated memories may destabilize and require restabilization processes to persist, referred to as reconsolidation. The reminder-extinction procedure has been proposed as a behavioral reconsolidation-based intervention to persistently attenuate threat-conditioned memories. After the presentation of a single reminder trial, the conditioned threat memory may enter a labile state, and extinction training during this window can prevent the return of conditioned threat responses. However, findings on this reminder-extinction procedure are mixed and its effectiveness may be subject to boundary conditions, inc...
Source: Behavioral Neuroscience - June 7, 2021 Category: Neuroscience Source Type: research
The primacy of behavioral research for understanding the brain.
Understanding the brain requires us to answer both what the brain does, and how it does it. Using a series of examples, I make the case that behavior is often more useful than neuroscientific measurements for answering the first question. Moreover, I show that even for “how” questions that pertain to neural mechanism, a well-crafted behavioral paradigm can offer deeper insight and stronger constraints on computational and mechanistic models than do many highly challenging (and very expensive) neural studies. I conclude that purely behavioral research is essential for understanding the brain—especially its cognitive f...
Source: Behavioral Neuroscience - June 7, 2021 Category: Neuroscience Source Type: research
Piecing together the orbitofrontal puzzle.
For almost a century, researchers have puzzled over how the orbitofrontal cortex (OFC) contributes to behavior. Our understanding of the functions of this area has evolved as each new finding and piece of information is added to complete the larger picture. Despite this, the full picture of OFC function is incomplete. Here we begin by reviewing recent (and not so recent) theories of how OFC contributes to behavior. We then go onto highlight emerging work that has helped to broaden perspectives on the role that OFC plays in contingent learning, interoception, and social behavior. How OFC contributes to these aspects of beha...
Source: Behavioral Neuroscience - May 31, 2021 Category: Neuroscience Source Type: research
The orbital frontal cortex, task structure, and inference.
The orbital frontal cortex (OFC) has long been linked to goal-directed, flexible behaviors. Recent evidence suggests the OFC plays key roles in representing the abstracted structure of task spaces, and using this representation for flexible inferences during both learning and choice. Here, we review convergent evidence from studies in animal models and humans in support of this view. We begin by considering early accounts of OFC function, then discuss how more recent evidence supports theories that have re-cast OFC’s function as representing the structure of a task or environment for flexible inference. Finally, we turn ...
Source: Behavioral Neuroscience - May 31, 2021 Category: Neuroscience Source Type: research
Bridging across functional models: The OFC as a value-making neural network.
Many functions have been attributed to the orbitofrontal cortex (OFC)—some classical roles, such as signaling the value of action outcomes, being challenged by more recent ones, such as signaling the position of a trial within a task space. In this paper, we propose a unifying neural network architecture, whose function is to generate a value from a set of attributes attached to a particular object. Our model reverses the logic of perceptual choice models, by considering values as outputs of (and not inputs to) the neural network. In doing so, the model explains why univariate value signals have been observed in both lik...
Source: Behavioral Neuroscience - May 31, 2021 Category: Neuroscience Source Type: research
The orbitofrontal cartographer.
Theories of orbitofrontal cortex (OFC) function have evolved substantially over the last few decades. There is now a general consensus that the OFC is important for predicting aspects of future events and for using these predictions to guide behavior. Yet the precise content of these predictions and the degree to which OFC contributes to agency contingent upon them has become contentious, with several plausible theories advocating different answers to these questions. In this review we will focus on three of these ideas—the economic value, credit assignment, and cognitive map hypotheses—describing both their successes ...
Source: Behavioral Neuroscience - May 31, 2021 Category: Neuroscience Source Type: research
Call for a more balanced approach to understanding orbital frontal cortex function.
Orbital frontal cortex (OFC) research has historically emphasized the function of this associative cortical area within top-down theoretical frameworks. This approach has largely focused on mapping OFC activity onto human-defined psychological or cognitive constructs and has often led to OFC circuitry bearing the weight of entire theoretical frameworks. New techniques and tools developed in the last decade have made it possible to revisit long-standing basic science questions in neuroscience and answer them with increasing sophistication. We can now study and specify the genetic, molecular, cellular, and circuit architectu...
Source: Behavioral Neuroscience - May 31, 2021 Category: Neuroscience Source Type: research
Heterogeneous value coding in orbitofrontal populations.
Value signals in the brain are important for learning, decision-making, and orienting behavior toward relevant goals. Although they can play different roles in behavior and cognition, value representations are often considered to be uniform and static signals. Nonetheless, contextual and mixed representations of value have been widely reported. Here, we review the evidence for heterogeneity in value coding and dynamics in the orbitofrontal cortex. We argue that this diversity plays a key role in the representation of value itself and allows neurons to integrate value with other behaviorally relevant information. We also di...
Source: Behavioral Neuroscience - May 31, 2021 Category: Neuroscience Source Type: research
