Aged Rats Exhibit Altered Behavior-Induced Oscillatory Activity, Place Cell Firing Rates, and Spatial Information Content in the CA1 Region of the Hippocampus.

Hippocampal gamma and theta oscillations are associated with mnemonic and navigational processes and adapt to changes in the behavioral state of an animal to optimize spatial information processing. It has been shown that locomotor activity modulates gamma and theta frequencies in rats, although how age alters this modulation has not been well studied. Here, we examine gamma and theta local-field potential and place cell activity in the hippocampus CA1 region of young and old male rats as they performed a spatial eye-blink conditioning task across 31 d.

The role of collegiality in academic review, promotion, and tenure.

Review, promotion, and tenure (RPT) processes at universities typically assess candidates along three dimensions: research, teaching, and service. In recent years, some have argued for the inclusion of a controversial fourth criterion: collegiality. While collegiality plays a role in the morale and effectiveness of academic departments, it is amorphic and difficult to assess, and could be misused to stifle dissent or enforce homogeneity.

How faculty define quality, prestige, and impact of academic journals.

Despite the calls for change, there is significant consensus that when it comes to evaluating publications, review, promotion, and tenure processes should aim to reward research that is of high "quality," is published in "prestigious" journals, and has an "impact." Nevertheless, such terms are highly subjective and present challenges to ascertain precisely what such research looks like. Accordingly, this article responds to the question: how do faculty from universities in the United States and Canada define the terms quality, prestige, and impact of academic journals? We address this question by surveying 338 faculty members from 55 different institutions in the U.

Why we publish where we do: Faculty publishing values and their relationship to review, promotion and tenure expectations.

Using an online survey of academics at 55 randomly selected institutions across the US and Canada, we explore priorities for publishing decisions and their perceived importance within review, promotion, and tenure (RPT). We find that respondents most value journal readership, while they believe their peers most value prestige and related metrics such as impact factor when submitting their work for publication. Respondents indicated that total number of publications, number of publications per year, and journal name recognition were the most valued factors in RPT.

Use of the Journal Impact Factor in academic review, promotion, and tenure evaluations.

We analyzed how often and in what ways the Journal Impact Factor (JIF) is currently used in review, promotion, and tenure (RPT) documents of a representative sample of universities from the United States and Canada. 40% of research-intensive institutions and 18% of master's institutions mentioned the JIF, or closely related terms. Of the institutions that mentioned the JIF, 87% supported its use in at least one of their RPT documents, 13% expressed caution about its use, and none heavily criticized it or prohibited its use.

How significant are the public dimensions of faculty work in review, promotion and tenure documents?

Much of the work done by faculty at both public and private universities has significant public dimensions: it is often paid for by public funds; it is often aimed at serving the public good; and it is often subject to public evaluation. To understand how the public dimensions of faculty work are valued, we analyzed review, promotion, and tenure documents from a representative sample of 129 universities in the US and Canada. Terms and concepts related to public and community are mentioned in a large portion of documents, but mostly in ways that relate to service, which is an undervalued aspect of academic careers.

The evaluation of scholarship in academic promotion and tenure processes: Past, present, and future.

Review, promotion, and tenure (RPT) processes significantly affect how faculty direct their own career and scholarly progression. Although RPT practices vary between and within institutions, and affect various disciplines, ranks, institution types, genders, and ethnicity in different ways, some consistent themes emerge when investigating what faculty would like to change about RPT. For instance, over the last few decades, RPT processes have generally increased the value placed on research, at the expense of teaching and service, which often results in an incongruity between how faculty actually spend their time vs.

Age-associated changes in waking hippocampal sharp-wave ripples.

Hippocampal sharp-wave ripples are brief high-frequency (120-250 Hz) oscillatory events that support mnemonic processes during sleep and awake behavior. Although ripples occurring during sleep are believed to facilitate memory consolidation, waking ripples may also be involved in planning and memory retrieval. Recent work from our group determined that normal aging results in a significant reduction in the peak oscillatory frequency and rate-of-occurrence of ripples during sleep that may contribute to age-associated memory decline.

Age Is Associated with Reduced Sharp-Wave Ripple Frequency and Altered Patterns of Neuronal Variability.

Unlabelled: Spatial and episodic memory performance declines with age, and the neural basis for this decline is not well understood. Sharp-wave ripples are brief (∼70 ms) high-frequency oscillatory events generated in the hippocampus and are associated with the consolidation of spatial memories. Given the connection between ripple oscillations and memory consolidation, we investigated whether the structure of ripple oscillations and ripple-triggered patterns of single-unit activity are altered in aged rats.

Tracking the course of hippocampal representations during learning: when is the map required?

Distinct ensembles of hippocampal cells can be active in numerous contexts, but specific "cognitive maps" tend to be retrieved on repeat visits to the same place. During aging, the reliability of map retrieval in CA1 networks is reduced; this provides a unique opportunity to investigate correlations between inconsistent activity patterns in circuits hypothesized to enable context encoding and hippocampus-dependent learning ability. Here, CA1 pyramidal cells were recorded in six young and six old rats, while memory for specific locations was probed using a place-dependent eyeblink conditioning task.

Reduced gamma frequency in the medial frontal cortex of aged rats during behavior and rest: implications for age-related behavioral slowing.

Age-related cognitive and behavioral slowing may be caused by changes in the speed of neural signaling or by changes in the number of signaling steps necessary to achieve a given function. In the mammalian cortex, neural communication is organized by a 30-100 Hz "gamma" oscillation. There is a putative link between the gamma frequency and the speed of processing in a neural network: the dynamics of pyramidal neuron membrane time constants suggest that synaptic integration is framed by the gamma cycle, and pharmacological slowing of gamma also slows reaction times on behavioral tasks.

Neural Protein Synthesis during Aging: Effects on Plasticity and Memory.

During aging, many experience a decline in cognitive function that includes memory loss. The encoding of long-term memories depends on new protein synthesis, and this is also reduced during aging. Thus, it is possible that changes in the regulation of protein synthesis contribute to the memory impairments observed in older animals.

Impaired hippocampal LTP in inbred mouse strains can be rescued by beta-adrenergic receptor activation.

Long-term potentiation (LTP), an activity-dependent enhancement of synaptic strength, and memory can be influenced by neuromodulatory transmitters such as norepinephrine (NE) and also by genetic background. beta-Adrenergic receptor activation can facilitate the expression of hippocampal CA1 LTP induced by weak stimulus patterns, but its influence on LTP induced by stronger stimulus patterns is unclear. We examined neural NE and dopamine (DA) levels, beta-adrenergic receptor expression and hippocampal LTP in genetically diverse inbred mouse strains.

Mouse models of impaired fear memory exhibit deficits in amygdalar LTP.

Inbred mouse strains have different genetic backgrounds that can result in impairments of synaptic plasticity and memory. They are valuable models for probing the mechanisms of memory impairments. We examined fear memory in several inbred strains, along with synaptic plasticity that may underlie fear memory.

Impaired fear memories are correlated with subregion-specific deficits in hippocampal and amygdalar LTP.

Inbred mouse strains have different genetic backgrounds that likely influence memory and long-term potentiation (LTP). LTP, a form of synaptic plasticity, is a candidate cellular mechanism for some forms of learning and memory. Strains with impaired fear memory may have selective LTP deficits in different hippocampal subregions or in the amygdala.

Selective modification of short-term hippocampal synaptic plasticity and impaired memory extinction in mice with a congenitally reduced hippocampal commissure.

The hippocampus is critical for forming new long-term memories, but the contributions of the hippocampal commissure (HC) to memory function and hippocampal synaptic plasticity are unclear. To shed light on this issue, we characterized behavioral memory and hippocampal synaptic plasticity in two inbred mouse strains. BALB/cWah1 mice display a range of corpus callosal defects and an intact HC, whereas 9XCA/Wah mice exhibit a complete absence of corpus callosum and a greatly reduced HC.