Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Despite the concern that has been expressed about potential method biases, and the pervasiveness of research settings with the potential to produce them, there is disagreement about whether they really are a problem for researchers in the behavioral sciences. Therefore, the purpose of this review is to explore the current state of knowledge about method biases. First, we explore the meaning of the terms “method” and “method bias” and then we examine whether method biases influence all measures equally. Next, we review the evidence of the effects that method biases have on individual measures and on the covariation between different constructs. Following this, we evaluate the procedural and statistical remedies that have been used to control method biases and provide recommendations for minimizing method bias.

Sources of Method Bias in Social Science Research and Recommendations on How to Control It

The field of neuroscience has, after a long period of looking the other way, again embraced emotion as an important research area. Much of the progress has come from studies of fear, and especially fear conditioning. This work has pin- pointed the amygdala as an important component of the system involved in the acqui- sition, storage, and expression of fear memory and has elucidated in detail how stimuli enter, travel through, and exit the amygdala. Some progress has also been made in understanding the cellular and molecular mechanisms that underlie fear conditioning, and recent studies have also shown that the findings from experimental animals apply to the human brain. It is important to remember why this work on emotion succeeded where past efforts failed. It focused on a psychologically well-defined aspect of emo- tion, avoided vague and poorly defined concepts such as "affect," "hedonic tone," or "emotional feelings," and used a simple and straightforward experimental approach. With so much research being done in this area today, it is important that the mistakes of the past not be made again. It is also time to expand from this foundation into broader aspects of mind and behavior

http://gruberpeplab.com/3131/LeDoux_2000_Emotioncircuitbrain.pdf

Emotion Circuits in the Brain

This article considers the role of the hippocampus in memory function. A central thesis is that work with rats, monkeys, and humans--which has sometimes seemed to proceed independently in 3 separate literatures--is now largely in agreement about the function of the hippocampus and related structures. A biological perspective is presented, which proposes multiple memory systems with different functions and distinct anatomical organizations. The hippocampus (together with anatomically related structures) is essential for a specific kind of memory, here termed declarative memory (similar terms include explicit and relational). Declarative memory is contrasted with a heterogeneous collection of nondeclarative (implicit) memory abilities that do not require the hippocampus (skills and habits, simple conditioning, and the phenomenon of priming). The hippocampus is needed temporarily to bind together distributed sites in neocortex that together represent a whole memory.

Memory and the hippocampus: A synthesis from findings with rats, monkeys, and humans.

The adolescent brain and age-related behavioral manifestations

A considerable body of evidence indicates that hippocampal circuitry is especially vulnerable to the neurodegeneration associated with normal and pathological aging. However, aged hippocampus appears to retain some of its capacity to regenerate in response to this damage [1–3]. Axonal sprouting and synaptic reorganization have been reported in hippocampal regions sustaining loss of cells or input during normal aging [2, 3]. Neurotrophic factors (NTFs) are believed to be necessary for such structural reorganization. One family of NTFs, the insulin-like growth factors (IGFs), may have actions on a broad spectrum of hippocampal cells [4–10]. This family of growth factors consists of two peptides, IGF-I and IGF-1I, which interact with two different receptors, the type 1 and type 2 IGF receptors (IGFR). The type 1 IGFR, which has high affinity for both IGFs, mediates many of the proliferative and differentiative actions of the IGFs [9, 10]. The functional role of the type 2 receptor, which has high affinity for IGF-II but low affinity for IGF-I, is not well defined [11–14]. The IGF system also includes a family of six IGF binding proteins (IGFBPs) that modulate IGF action and availability in tissue-, cell-, and development-specific manners [9,10].

Insulin-like Growth Factor I: Regulation and Interactions During Aging-Induced Cognitive Decline and Impairment Within the Hippocampus

This invention relates to novel extended release pharmaceutical compositions of levetiracetam and preparations and characterizations thereof. This invention further relates to using these extended release pharmaceutical compositions of levetiracetam for the treatment of cognitive impairment associated with central nervous system (CNS) disorders in a subject in need or at risk thereof.

Extended release pharmaceutical compositions of levetiracetam

Age-related memory deficits are correlated with neural hyperactivity in the CA1 and CA3 regions of the hippocampus. Abnormal CA3 hyperactivity in aged rats has been proposed to contribute to an imbalance between the normal tradeoff between pattern separation and pattern completion, resulting in overly rigid representations. Recent evidence of functional heterogeneity along the CA3 transverse axis suggests that proximal CA3 supports pattern separation while distal CA3 supports pattern completion. It is not known whether age-related CA3 hyperactivity is uniformly represented along the CA3 transverse axis. We examined the firing rates of CA3 neurons from male young and aged Long-Evans rats along the CA3 transverse axis. Consistent with prior studies, young CA3 cells showed an increasing gradient in mean firing rate from proximal to distal CA3. However, aged CA3 cells showed an opposite trend, with a decreasing gradient from proximal to distal CA3. Thus, CA3 cells in aged rats were hyperactive in proximal CA3, but possibly hypoactive in distal CA3, compared to young rats. We suggest that, in combination with altered inputs from the entorhinal cortex and dentate gyrus, the proximal CA3 region of aged rats may switch from its normal function that reflects the pattern separation output of the DG and instead performs a computation that reflects an abnormal bias toward pattern completion. In parallel, distal CA3 of aged rats may create weaker attractor basins that promote bistable representations under certain conditions.

https://biorxiv.org/content/10.1101/2020.08.31.275156v1.full.pdf

Heterogeneity of age-related neural hyperactivity along the CA3 transverse axis

L'invention concerne des procedes d'identification de genes impliques dans un trouble cognitif et des compositions permettant de traiter un tel trouble.

Cible destinee a la therapie d'un trouble cognitif

The lateral habenula (LHb) has been implicated in conditioned inhibition. Here, the modulating effects of LHb activity on the association of a conditioned stimulus (CS) with the nonoccurrence of an unconditioned stimulus (US) were assessed in vivo using chemogenetic methods. Animals initially received explicitly unpaired CS light and US food presentations. Animals subjected to a retardation-of-acquisition task subsequently underwent light and food pairings, whereas those subjected to a summation task underwent compound light-tone and food pairings. The inhibitory light strength was assessed based on retardation of the acquisition of food-cup conditioned responses (CRs) in light-food pairings and comparisons of food-cup CRs to each stimulus in a CS-alone test following compound training. Neurotoxic LHb lesions and chemogenetic LHb inhibition throughout unpaired training attenuated the inhibitory light strength. Furthermore, chemogenetic LHb activation accelerated the decline in CR induced by repeated light-alone presentations following light-food pairings. Therefore, the LHb critically contributes to conditioned inhibition.

Michela Gallagher

Papers

Insulin-like Growth Factor I: Regulation and Interactions During Aging-Induced Cognitive Decline and Impairment Within the Hippocampus

Extended release pharmaceutical compositions of levetiracetam

Heterogeneity of age-related neural hyperactivity along the CA3 transverse axis

Cible destinee a la therapie d'un trouble cognitif

The lateral habenula mediates the association of a conditioned stimulus with the absence of an appetitive unconditioned stimulus