Disruption of the anterior thalamic head direction signal following reduction of the hippocampal theta rhythm.
There is overlap between the structures containing head direction (HD) cells and those mediating the hippocampal theta rhythm, and both signals are thought to play an important role in spatial navigation. Previous research has shown that reversible inactivation of the medial septum attenuates hippocampal theta activity and disrupts path integration-based navigation. Although the HD signal reflects navigational performance, it is unclear whether theta rhythm contributes to the direction-specific activity of HD cells. We sought to determine whether HD cell activity is changed following reversible inactivation of the medial s...
Source: Behavioral Neuroscience - February 11, 2021 Category: Neuroscience Source Type: research
Instantaneous amplitude and shape of postrhinal theta oscillations differentially encode running speed.
Hippocampal theta oscillations have a temporally asymmetric waveform shape, but it is not known if this theta asymmetry extends to all other cortical regions involved in spatial navigation and memory. Here, using both established and improved cycle-by-cycle analysis methods, we show that theta waveforms in the postrhinal cortex are also temporally asymmetric. On average, the falling phase of postrhinal theta cycles lasts longer than the subsequent rising phase. There are, however, rapid changes in both the instantaneous amplitude and instantaneous temporal asymmetry of postrhinal theta cycles. These rapid changes in amplit...
Source: Behavioral Neuroscience - February 11, 2021 Category: Neuroscience Source Type: research
Theta rhythm across the species: Bridging inconsistencies with a multiple memory systems approach.
The discovery of movement-modulated 7–8 Hz theta rhythm in rodents provided one of the earliest indications of synchronicity of neuronal firing in the hippocampus. Subsequent research expanded on this finding on theta rhythm and its role in other domains such as spatial navigation and memory. Nevertheless, discrepancies among animal models posed the question of how well the animal literature represents human mechanisms. Technological advances have since facilitated research taking place directly in humans, typically neurosurgical patients implanted with intracranial electrodes. Human studies have observed lower frequency...
Source: Behavioral Neuroscience - February 11, 2021 Category: Neuroscience Source Type: research
Floating ideas on theta waves.
This special issue on the theta rhythm highlights recent experiments aimed at understanding the relationship between this slow, large amplitude oscillation and plasticity, fast oscillations, cellular activity and disease in both animals and humans. The articles in this issue of Behavioral Neuroscience use a number of approaches across different model systems and behavioral paradigms to provide an up-to-date account of recent progress in understanding how the theta rhythm coordinates neural activity in the service of cognition. Prominent themes that emerge are how theta is tightly related to movement in humans and rodents a...
Source: Behavioral Neuroscience - February 11, 2021 Category: Neuroscience Source Type: research
Cholinergic modulation of hippocampally mediated attention and perception.
We examined cholinergic modulation on an attention task that recruits the hippocampus. On each trial, participants viewed two images (rooms with paintings). On “similar room” trials, they judged whether the rooms had the same spatial layout from a different perspective. On “similar art” trials, they judged whether the paintings could have been painted by the same artist. On “identical” trials, participants simply had to detect identical paintings or rooms. We hypothesized that cholinergic modulation would improve performance on the similar room task, given past findings that hippocampal representations predicte...
Source: Behavioral Neuroscience - November 5, 2020 Category: Neuroscience Source Type: research
Renewal of goal direction with a context change after habit learning.
An instrumental action can be goal-directed after a moderate amount of practice and then convert to habit after more extensive practice. Recent evidence suggests, however, that habits can return to action status after different environmental manipulations. The present experiments therefore asked whether habit learning interferes with goal direction in a context-dependent manner like other types of retroactive interference (e.g., extinction, punishment, counterconditioning). In Experiment 1, rats were given a moderate amount of instrumental training to form an action in one context (Context A) and then more extended trainin...
Source: Behavioral Neuroscience - October 29, 2020 Category: Neuroscience Source Type: research
GPR52 agonists attenuate ropinirole-induced preference for uncertain outcomes.
Dopamine D2/3 receptor agonists are less likely to trigger dyskinesias than L-dopa while still offering relief from the motor symptoms of Parkinson’s disease (PD). However, these drugs can cause serious impulse control problems and gambling disorders. Adjunctive therapies capable of blocking these side effects without impacting the antiparkinsonian effect would be clinically useful. G-protein-coupled receptor 52 (GPR52) is an orphan Gs-protein-coupled receptor that is coexpressed with striatal D₂ receptors. Activating GPR52 attenuates behaviors associated with increased striatal dopamine release without altering basal ...
Source: Behavioral Neuroscience - October 29, 2020 Category: Neuroscience Source Type: research
Olfactory recognition memory in mice depends on task parameters.
We use a simple two-trial odor recognition paradigm to test memory duration, span, and specificity in adult mice. Our paradigm allows mice to encode and/or recall multiple odors in one trial and necessitates no training or food/water deprivation. We show that this paradigm can be used for encoding and/or testing of multiple odors in single trials, leading to shorter behavioral testing. Using this simple paradigm, we show that mice can remember a single odor for up to 10 but no more than 15 min and two odors for up to 5 min. Mice could not remember 3 odors at any delays tested here. We also show that specificity for the enc...
Source: Behavioral Neuroscience - October 22, 2020 Category: Neuroscience Source Type: research
Chronic social defeat stress mouse model: Current view on its behavioral deficits and modifications.
Stress is the main cause of mood disorders such as depression and posttraumatic stress disorder. Individuals respond to stress differently, as some develop depressive symptoms, whereas others successfully cope with adversity, but it remains unclear what makes some particularly vulnerable to stress. The chronic social defeat stress (CSDS) mouse model, an ethologically valid rodent model that exhibits long-term physiological and behavioral phenotypes similar to depression and anxiety, can imitate individual differences in stress responses in humans. In this review, we not only summarize various behavioral deficits of the CSD...
Source: Behavioral Neuroscience - October 22, 2020 Category: Neuroscience Source Type: research
Role of dorsal and ventral hippocampal muscarinic receptor activity in acquisition and retention of contextual fear conditioning.
This study advances understanding of the neurobiology of the CPFE by showing that context-shock associations are not learned following disruption of the cholinergic and/or hippocampal function on either the preexposure or training day. Existing theories of the CPFE (Rudy, 2009) have inferred this effect based on impaired 24-hr retention observed in previous studies (Matus-Amat, Higgins, Barrientos, & Rudy, 2004; Robinson-Drummer et al., 2016). However, the present study is the first to demonstrate it directly by including a postshock freezing measure. Further, this study is the first to identify vHPC as another important r...
Source: Behavioral Neuroscience - October 1, 2020 Category: Neuroscience Source Type: research
Global study of variability in olfactory sensitivity.
Variability in human olfactory sensitivity has been attributed to individual-level factors such as genetics, age, sex, medical history of infections and trauma, neurogenerative diseases, and emotional disorders. Scarce evidence exists on the cross-cultural variation in olfactory sensitivity. Hence, we performed 2 studies to estimate the variability in olfactory threshold as a function of location and environment. Study 1 involved 11 laboratories from 4 continents (N = 802). In each location, in a designated laboratory, approximately 80 subjects underwent olfactory sensitivity testing with custom-made tests with eucalyptol ...
Source: Behavioral Neuroscience - October 1, 2020 Category: Neuroscience Source Type: research
Examining changes in rodent temperament following repetitive mild traumatic brain injury in adolescence.
Mild traumatic brain injuries are known to cause a host of symptoms, including headaches, nausea, and depression, that when persistent, are known as postconcussive syndrome. In addition to these overt symptomologies, individuals may experience changes in day-to-day behavior or temperament, which although not meeting criteria for postconcussive diagnosis, does cause distress to the individual. The aim of this study was to determine whether we could measure temperament in a rat and, if so, determine whether temperament is altered in response to repetitive mild traumatic brain injuries (RmTBI). Forty male and female adolescen...
Source: Behavioral Neuroscience - October 1, 2020 Category: Neuroscience Source Type: research
No evidence that prefrontal HD-tDCS influences cue-induced food craving.
This study investigated whether the application of high definition transcranial DC stimulation (HD-tDCS) to the dorsolateral prefrontal cortex reduces cue-induced food craving when combined with food-specific inhibitory control training. Using a within-subjects design, participants (N = 55) received both active and sham HD-tDCS across 2 sessions while completing a Go/No-Go task in which foods were either associated with response inhibition or response execution. Food craving was measured pre and post stimulation using a standardized questionnaire as well as desire to eat ratings for foods associated with both response inhi...
Source: Behavioral Neuroscience - October 1, 2020 Category: Neuroscience Source Type: research
The ever-changing OFC landscape: What neural signals in OFC can tell us about inhibitory control.
Despite decades of research on OFC function, the exact function(s) of OFC remain elusive. In recent years, 1 of the earliest hypotheses about OFC function, namely its involvement in inhibitory control, has drifted to the periphery of the functional OFC landscape in favor of theories suggesting a role for OFC in the representation of task or state space. The reasons for this drift are valid, owing in part to the development of more sensitive behavioral approaches, a clear emphasis on cross-species and cross-method comparisons, as well as the elegant integration of reinforcement learning theories. However, recent evidence re...
Source: Behavioral Neuroscience - September 10, 2020 Category: Neuroscience Source Type: research
Female rats take longer than male rats to update reward expectancies when outcomes are worse than expected.
The ability to update predictive relationships and adjust behavior accordingly is critical for survival. Females take longer to update expectancies under conditions of outcome omission. It remains unknown whether that is also the case under conditions when outcomes are delivered such as in overexpectation. Here we examined whether male and female rats are able to learn from overexpectation using the same learning parameters. Our data show that males but not females learn from overexpectation when given just a single day of compound training, whereas both sexes learn when given extended 2 days of overexpectation training. T...
Source: Behavioral Neuroscience - August 6, 2020 Category: Neuroscience Source Type: research
