Isolated Partial Absence of the Septum Pellucidum: A Case Report.

The septum pellucidum is an important thin, membranous structure in the brain that separates the anterior horns of the lateral ventricles, essential for maintaining brain anatomy and function. Here, we describe a case of a 38-year-old male with a 20-year history of seizures, occurring approximately three to four times annually and lasting 30 minutes to one hour per episode, who presented with a recent seizure three days prior. Magnetic resonance imaging (MRI) of the brain revealed an absence of the septum pellucidum in its posterior portion, mild prominence of both lateral ventricles, and an abnormal course of the crura of the fornix, leading to a diagnosis of partial absence of the septum pellucidum. This case underscores the importance of comprehensive neuroimaging in detecting structural brain anomalies, which is crucial for effective diagnosis, management, and improving patient outcomes, particularly in long-standing seizure disorders.

Outcomes of conjunctivochalasis treatment after fornix deepening with retractor recession and repositioning.

PURPOSE: To evaluate outcomes of fornix deepening with retractor recession and repositioning for conjunctivochalasis (CCh) on improvement of conjunctival folds and ocular surface symptoms, particularly epiphora. METHODS: Retrospective, single-centre, observational case series of patients with refractory CCh who underwent fornix deepening and retractor recession. CCh was graded using the Hoh classification (grades 0 to 3 depending on the number and height of folds). Epiphora, reflex tearing, and dry eye symptoms were assessed using the validated 'TEAR' score pre- and post-CCh correction. RESULTS: 18 eyes of 11 patients with CCh (average age 68, range 46-82 years) were treated with fornix deepening and retractor recession. All had shallow fornices pre-operatively with a mean CCh grade of 1.7 (typically lower than the tear meniscus). Locations of the folds were variable: diffuse/middle (n = 10), nasal (n = 4), and temporal (n = 4). At 15-month mean follow-up, conjunctival redundancy was absent in 17 of 18 eyes postoperatively, resulting in a restored tear meniscus and reservoir. 91% saw a reduction in tearing frequency (T), with 73% gaining ≥ 2-point improvement. Improvements in clinical effects (E) and activity limitation (A) were seen in 82% and 91% of patients, respectively, with 36% and 64% gaining ≥ 2-point improvement. R scores (related to reflex tearing) improved in 73%, with 64% seeing ≥ 2-point gains. (P < 0.05 for all). CONCLUSION: Restoration of the tear reservoir by inferior fornix deepening with retractor recession and repositioning can result in improvement of CCh and epiphora.

Drug Delivery Systems for Glaucoma: A Narrative Review.

Glaucoma is one of the world's leading causes of blindness, and its management is challenging. The main objective is to lower intraocular pressure through medical, para-surgical, and surgical therapy. Medical therapy often represents the first line of treatment. Although effective in many cases, the eye drops are accompanied by significant problems. They require high patient compliance and can be associated with various side effects, limiting their efficacy. Consequently, the research for new drug delivery systems trying to overcome these limitations is ongoing: numerous devices are developing and gradually entering clinical practice. These new therapeutic options may offer better control of the intraocular pressure, with fewer side effects, and are less dependent on patients' compliance. Hence, the research in this field continues to flourish. This review summarizes the most recent findings in the scientific literature, underlines the role and possible limitations of the new glaucoma drug delivery systems in clinical practice, and recognizes their new horizons and perspectives.

Drawing promotes memory retention in a patient with sleep-related anterograde amnesia.

Drawing is a powerful tool to enhance memory in healthy participants and patients with probable dementia. Here, we investigated whether the drawing effect could extend to patient CT, a young woman with severe anterograde amnesia. Following surgery for a midline tumor involving her septum pellucidium and extending down into her fornices bilaterally, CT experienced a severe case of sleep-related amnesia. She can remember information encountered throughout the day, but when waking up in the morning or following a nap she forgets information learned prior to sleep. Here, we tested CT and 21 age-matched controls in a 3-day within-subjects design, during which participants encoded words by either drawing or writing them down. Memory for encoded words was tested in two conditions that each followed a 12-h delay, once after a night of sleep, and once after 12 h of wake. Despite her severe memory impairment, CT showed a drawing effect that was comparable to controls in both sleep and wake conditions. Whereas CT's memory for written words was consistently impaired relative to controls, her memory for drawn words was at the lower control range following a waking delay and above chance following a sleep delay. We suggest that amnesic patients may benefit from the drawing effect due to the recruitment of brain regions outside of the hippocampal system for encoding and consolidation. Furthermore, in control participants, sleep benefited memory for written words, but not for drawn words, suggesting that sleep preferentially consolidates memories that are more dependent on the hippocampal system.

Utilizing diffusion tensor imaging as an image biomarker in exploring the therapeutic efficacy of forniceal deep brain stimulation in a mice model of Alzheimer's disease.

Objective.With prolonged life expectancy, the incidence of memory deficits, especially in Alzheimer's disease (AD), has increased. Although multiple treatments have been evaluated, no promising treatment has been found to date. Deep brain stimulation (DBS) of the fornix area was explored as a possible treatment because the fornix is intimately connected to memory-related areas that are vulnerable in AD; however, a proper imaging biomarker for assessing the therapeutic efficiency of forniceal DBS in AD has not been established.Approach.This study assessed the efficacy and safety of DBS by estimating the optimal intersection volume between the volume of tissue activated and the fornix. Utilizing a gold-electroplating process, the microelectrode's surface area on the neural probe was increased, enhancing charge transfer performance within potential water window limits. Bilateral fornix implantation was conducted in triple-transgenic AD mice (3 × Tg-AD) and wild-type mice (strain: B6129SF1/J), with forniceal DBS administered exclusively to 3 × Tg-AD mice in the DBS-on group. Behavioral tasks, diffusion tensor imaging (DTI), and immunohistochemistry (IHC) were performed in all mice to assess the therapeutic efficacy of forniceal DBS.Main results.The results illustrated that memory deficits and increased anxiety-like behavior in 3 × Tg-AD mice were rescued by forniceal DBS. Furthermore, forniceal DBS positively altered DTI indices, such as increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD), together with reducing microglial cell and astrocyte counts, suggesting a potential causal relationship between revised FA/MD and reduced cell counts in the anterior cingulate cortex, hippocampus, fornix, amygdala, and entorhinal cortex of 3 × Tg-AD mice following forniceal DBS.Significance.The efficacy of forniceal DBS in AD can be indicated by alterations in DTI-based biomarkers reflecting the decreased activation of glial cells, suggesting reduced neural inflammation as evidenced by improvements in memory and anxiety-like behavior.

Synergistic effects of GFAP and Aß42: Implications for white matter integrity and verbal memory across the cognitive spectrum.

Background: Plasma glial fibrillary acidic protein (GFAP), an astrocytic biomarker, has previously been linked with Alzheimer's disease (AD) status, amyloid levels, and memory performance in older adults. The neuroanatomical pathways by which astrogliosis/astrocyte reactivity might impact cognitive outcomes remains unclear. We evaluated whether plasma GFAP and amyloid levels had a synergistic effect on fornix structure, which is critically involved in AD-associated cholinergic pathways. We also examined whether fornix structure mediates associations between GFAP and verbal memory. Methods: In a cohort of both asymptomatic and symptomatic older adults (total n = 99), we assessed plasma GFAP, amyloid-ß42 (Aß42), other AD-related proteins, and vascular markers, and we conducted comprehensive memory testing. Tractography-based methods were used to assess fornix structure with whole brain diffusion metrics to control for diffuse alterations in brain white matter. Results: In individuals in the low plasma amyloid-ß42 (Aß42) group, higher plasma GFAP was associated with lower fractional anisotropy (FA; p = 0.007), higher mean diffusivity (MD; p < 0.001), higher radial diffusivity (RD; p < 0.001), and higher axial diffusivity (DA; p = 0.001) in the left fornix. These associations were independent of APOE gene status, plasma levels of total tau and neurofilament light, plasma vascular biomarkers, and whole brain diffusion metrics. In a sub-analysis of participants in the low plasma Aß42 group (n = 33), fornix structure mediated the association between higher plasma GFAP levels and lower verbal memory performance. Discussion: Higher plasma GFAP was associated with altered fornix microstructure in the setting of greater amyloid deposition. We also expanded on our prior GFAP-verbal memory findings by demonstrating that in the low plasma Aß42 group, left fornix integrity may be a primary white matter conduit for the negative associations between GFAP and verbal memory performance. Overall, these findings suggest that astrogliosis/astrocyte reactivity may play an early, pivotal role in AD pathogenesis, and further demonstrate that high GFAP and low Aß42 in plasma may reflect a particularly detrimental synergistic role in forniceal-memory pathways.

Superior rectus/levator complex in acquired anophthalmic socket repaired with spheric implant-a computed tomography scan and topographic study.

AIM: To determine whether the levator palpebrae superioris (LPS)/superior rectus (SR) muscle complex, can influence the position of the upper lid and fornix in acquired anophthalmic sockets. METHODS: This comparative non-randomized and non-interventional study included retrospective data of 21 patients with unilateral acquired anophthalmic sockets repaired with spheric implants. High-resolution computed tomography (CT) measurements of the LPM/SR muscle complex and clinical topographic position of the upper lid, superior and inferior fornix depth in primary gaze position were evaluated. Demographic data were presented as frequency and percentage proportions and quantitative variables comparing the socket measurements with the normal contralateral orbit was statistically analyzed using non-parametric tests considering P<0.05. RESULTS: The anophthalmic orbits had a significantly shorter LPS length (P=0.01) and significantly thicker SR (P=0.02) than the normal orbit. Lagophthalmos was present in anophthalmic sockets but not in normal orbits (P=0.002), while levator function was normal in both (P>0.05, all comparisons). The superior fornix depth was similar in the anophthalmic socket and the contralateral normal orbit (P=0.192) as well the inferior fornix depth (P=0.351). CONCLUSION: Acquired anophthalmic sockets repaired with spheric implants have shorter LPS, thicker SR, and more lagophthalmos than normal orbits. The relationship of the LPS and SR with other orbital structures, associated with passive or active forces acting in the final position of the lids and external ocular prosthesis should be further investigated.

A Critical Examination of Ligamentous Pathogenesis of Bladder Pain/Lower Urinary Tract Symptoms Using the UEDA Criteria.

To critically analyse the relationship of bladder pain syndrome (BPS/IC), as defined, to the posterior fornix syndrome, "PFS" predictably co-occurring bladder urgency, frequency, nocturia, chronic pelvic pain, emptying symptoms/retention, caused by uterosacral ligament (USL) laxity and cured by USL repair. The starting and end points of this paper are the questions, "Are there arguments that BPS/IC can, in some cases, be linked to PFS?" And if so, "To what extent?" We used the criteria required by Ueda for proper diagnosis: "understanding symptoms, detecting abnormal findings and verifying them as a cause of the symptoms." Literature, diagnostic and surgical, indicate that chronic pelvic pain "of unknown origin" can be caused by unsupported visceral pelvic plexuses because of weak USLs; these cause fire of afferent impulses, which the brain mistakenly interprets as coming from the end-organ itself (i.e., genitourinary pain, lower urinary tract symptoms). The same lax USLs can also weaken the pelvic muscles which contract to stretch the vagina to support the urothelial stretch receptors from below: these may prematurely fire off afferent impulses to activate micturition at lower bladder volumes, interpreted as urgency. A speculum placed in the vagina can relieve pain and urgency by mechanically supporting the vaginal wall and USLs, thus predicting an eventual cure by USL repair. There is need to evaluate what percentage of women with known BPS/IC also pass the criteria for PFS. Identifying a significant percentage of BPS/IC women with the causative relation between PFS pathogenesis and BPS/ IC may open a new way of diagnosing and treating BPS/IC in some women.

A Hypothesis for Anatomical Pathways of Chronic Pelvic Pain of "Unknown Origin".

BACKGROUND: Interstitial cystitis/bladder pain syndrome (IC/BPS) is a disabling bladder condition. ESSIC, the IC/BPS society defines two types of IC/BPS: with Hunner's lesion (HL) and without. Pathogenesis is stated as unknown, with no cure possible. Scheffler in 2021 reported cystoscopically validated cure of HL IC/BPS by repair of uterosacral ligaments (USLs) and in 2022, Goeschen reported non-HL IC/BPS cure in 198 women following USL repair. Both Scheffler and Goeschen hypothesized IC/BPS may be a phenotype of the Integral Theory's Posterior Fornix Syndrome "PFS" (chronic pelvic pain, OAB, and emptying dysfunctions) and therefore potentially curable. SUMMARY: The hypothesis explores whether visceral plexuses (VPs), due to weakened USLs support, serve as a primary source of pelvic pain impulses, leading to development of an inflammatory condition - for example, IC/BPS, a chronic inflammatory condition, which shares similarities with vulvodynia and complex regional pain syndrome (CRPS). According to our hypothesis, such conditions involve axon reflexes. Stimuli such as gravity applied to unsupported nerve branches within the visceral pelvic plexus, trigger centrally propagating impulses, which then progress antidromally to influence innervated tissues through cytokine release and nociceptor stimulation, perpetuating inflammatory processes at the end organs, and pain perception. KEY MESSAGES: The hypothesis raises the question, "are IC/BPS, vulvodynia, other pain sites, even nonbacterial "chronic prostatitis" in the male, different phenotypes of the chronic pelvic pain syndrome which includes PFS. If so, the hypothesis opens several new research directions and would predict inflammatory findings in tender end organ pain sites.

Cognitive and brain morphological deviations in middle-to-old aged autistic adults: A systematic review and meta-analysis.

Cognitive challenges and brain structure variations are common in autism spectrum disorder (ASD) but are rarely explored in middle-to-old aged autistic adults. Cognitive deficits that overlap between young autistic individuals and elderlies with dementia raise an important question: does compromised cognitive ability and brain structure during early development drive autistic adults to be more vulnerable to pathological aging conditions, or does it protect them from further decline? To answer this question, we have synthesized current theoretical models of aging in ASD and conducted a systematic literature review (Jan 1, 1980 - Feb 29, 2024) and meta-analysis to summarize empirical studies on cognitive and brain deviations in middle-to-old aged autistic adults. We explored findings that support different aging theories in ASD and addressed study limitations and future directions. This review sheds light on the poorly understood consequences of aging question raised by the autism community to pave the way for future studies to identify sensitive and reliable measures that best predict the onset, progression, and prognosis of pathological aging in ASD.

Interstitial cystitis/bladder pain syndrome: when part of the posterior fornix syndrome is potentially curable surgically.

Interstitial cystitis/bladder pain syndrome (IC/BPS) is defined as chronic pelvic pain plus a bladder symptom, usually urge. Evidence is offered to show IC/BPS forms part of the posterior fornix syndrome (PFS), which was defined in 1993 as: chronic pelvic pain (CPP), urge, frequency, nocturia, abnormal emptying, post-void residual urine, caused by uterosacral ligament (USL) laxity and cured or improved by USL repair. The IC/BPS definition implies that the urge and pain of IC/BPS is from a single (as yet unknown) pathogenic origin. However, when urge and pain are viewed from the perspective of the PFS, though both have the same lax USL origin, the anatomical pathway from lax USL to symptom manifestation is very different manifestation. For CPP the anatomical pathway is the inability of loose USLs to support pelvic visceral plexuses (VPs); it is hypothesized that inability of weak USLs to mechanically supports VPs, the afferent nerve synapse from end organs may fire off autologous afferent impulses to the brain which interprets them as pain from end organs such as urothelium, vulva, lower abdomen. For urge, the anatomical pathway is very different: lax USLs weaken the directional pelvic muscle forces which stretch the vagina to support the urothelial stretch receptors. The receptors fire off afferent impulses to the cortex at a lower bladder volume, and these are interpreted as "urge to go". Mechanical support of USLs relieves both pain and urge, as does USL repair.

Pubourethral and uterosacral male analogues suggest parallel male/female pelvic anatomy and symptom pathogenesis.

The thesis that functional/dysfunctional male/female pelvic floor anatomy are parallel, originated from two studies: a successful retropubic perineal male sling for post-prostatectomy stress urinary incontinence (SUI) and discovery of a male uterosacral ligament (USL) analogue, we named "prostatosacral ligament" (PSL). In 25 out of the studied 27 males (92.6%), it starts on both sides of the median sulcus of the prostate the ligament passes lateral to the rectum being fused with the lateral margin of the mesorectum before leaving it as it thins out to be attached posteriorly similar to the USL. The ultrasound data during straining in men and women showed the same three oppositely acting muscle vectors contracting around analogous ligaments, puboprostatic ligament (PPL) (male), and pubourethral ligament (PUL) (female). Further parallels were pubovesical ligaments (PVLs) and arc of Gilvernet as part of the continence and micturition mechanisms. Impressive evidence for parallel anatomy came from the successful cure of 22 males with post-prostatectomy SUI using a perineal retropubic tissue fixation system (TFS) minisling applied to the PPL using a similar methodology to that used in the female for PUL midurethral sling repair for cure of SUI. Laparoscopic evidence confirmed the prostate as a male analogue of the cervix, and PSLs as analogues of USLs: PSL origin from the prostate attached laterally to the mesorectum and inserted into the sacrum. Histologically, PSLs had identical features with USLs: collagen, elastin, smooth muscle, blood vessels and nerves. Virtually identical symptoms for "chronic prostatitis" (CP) and "posterior fornix syndrome" (PFS), such as chronic pelvic pain, overactive bladder (OAB), abnormal emptying, gave birth to the hypothesis, of a common pathogenesis for "CP" and "PFS", USL (or PSL) laxity. If this could be proven by "simulated operations", "CP", at least in theory, may be potentially correctible by PSL repair.

Targeting papez circuit for cognitive dysfunction- insights into deep brain stimulation for Alzheimer's disease.

Hippocampus is the most widely studied brain area coupled with impairment of memory in a variety of neurological diseases and Alzheimer's disease (AD). The limbic structures within the Papez circuit have been linked to various aspects of cognition. Unfortunately, the brain regions that include this memory circuit are often ignored in terms of understanding cognitive decline in these diseases. To properly comprehend where cognition problems originate, it is crucial to clarify any aberrant contributions from all components of a specific circuit -on both a local and a global level. The pharmacological treatments currently available are not long lasting. Deep Brain Stimulation (DBS) emerged as a new powerful therapeutic approach for alleviation of the cognitive dysfunctions. Metabolic, functional, electrophysiological, and imaging studies helped to find out the crucial nodes that can be accessible for DBS. Targeting these nodes within the memory circuit produced significant improvement in learning and memory by disrupting abnormal circuit activity and restoring the physiological network. Here, we provide an overview of the neuroanatomy of the circuit of Papez along with the mechanisms and various deep brain stimulation targets of the circuit structures which could be significant for improving cognitive dysfunctions in AD.

Altered fornix integrity is associated with sleep apnea-related hypoxemia in mild cognitive impairment.

INTRODUCTION: The limbic system is critical for memory function and degenerates early in the Alzheimer's disease continuum. Whether obstructive sleep apnea (OSA) is associated with alterations in the limbic white matter tracts remains understudied. METHODS: Polysomnography, neurocognitive assessment, and brain magnetic resonance imaging (MRI) were performed in 126 individuals aged 55-86 years, including 70 cognitively unimpaired participants and 56 participants with mild cognitive impairment (MCI). OSA measures of interest were the apnea-hypopnea index and composite variables of sleep fragmentation and hypoxemia. Microstructural properties of the cingulum, fornix, and uncinate fasciculus were estimated using free water-corrected diffusion tensor imaging. RESULTS: Higher levels of OSA-related hypoxemia were associated with higher left fornix diffusivities only in participants with MCI. Microstructure of the other white matter tracts was not associated with OSA measures. Higher left fornix diffusivities correlated with poorer episodic verbal memory. DISCUSSION: OSA may contribute to fornix damage and memory dysfunction in MCI. HIGHLIGHTS: Sleep apnea-related hypoxemia was associated with altered fornix integrity in MCI. Altered fornix integrity correlated with poorer memory function. Sleep apnea may contribute to fornix damage and memory dysfunction in MCI.

Metastases and Primary Brain Tumors Affecting the Fornix of the Brain.

Background The aim of this study is to evaluate the clinical and radiological findings of metastatic tumors and primary brain tumors affecting the fornix. Methods  Between January 2015 and March 2023, we retrospectively evaluated 1087 patients of both sexes who underwent cranial magnetic resonance imaging (MRI) for a preliminary diagnosis of intracranial malignancy in the radiology department of our hospital. Two radiologists with six and 10 years of experience in MRI examination assessed the relationship between primary and metastatic tumors and the fornix. Results  Involvement of the fornix was diagnosed in 29 of the 1087 patients (2.66%), of which fornix was affected by metastatic lesions in 14 patients (48.2%) and primary tumors in 15 patients (51.7%). The majority of metastatic lesions were from lung and breast cancers, with other tumor types including osteosarcoma, renal cell carcinoma, pancreatic adenocarcinoma, pleomorphic sarcoma, and diffuse large B-cell lymphoma. Among all primary tumors, glioblastoma was the most common primary brain tumor invading the fornix, with other diagnoses including diffuse astrocytoma, medulloblastoma, and anaplastic oligodendroglioma. Metastatic and primary brain tumors affecting the fornix were detected over a broad timeline, from the time of diagnosis up to 120 months after diagnosis. A retrospective evaluation of medical records revealed memory deficits in four patients. Conclusion The fornix can be affected by both metastatic and primary brain tumors. It is crucial to understand the relevant neuroanatomical relationships when evaluating lesions that affect the fornix.

Multi-shell diffusion MRI of the fornix as a biomarker for cognition in Alzheimer's disease.

BACKGROUND AND PURPOSE: A substantial fraction of those who had Alzheimer's Disease (AD) pathology on autopsy did not have dementia in life. While biomarkers for AD pathology are well-developed, biomarkers specific to cognitive domains affected by early AD are lagging. Diffusion MRI (dMRI) of the fornix is a candidate biomarker for early AD-related cognitive changes but is susceptible to bias due to partial volume averaging (PVA) with cerebrospinal fluid. The purpose of this work is to leverage multi-shell dMRI to correct for PVA and to evaluate PVA-corrected dMRI measures in fornix as a biomarker for cognition in AD. METHODS: Thirty-three participants in the Cleveland Alzheimer's Disease Research Center (CADRC) (19 with normal cognition (NC), 10 with mild cognitive impairment (MCI), 4 with dementia due to AD) were enrolled in this study. Multi-shell dMRI was acquired, and voxelwise fits were performed with two models: 1) diffusion tensor imaging (DTI) that was corrected for PVA and 2) neurite orientation dispersion and density imaging (NODDI). Values of tissue integrity in fornix were correlated with neuropsychological scores taken from the Uniform Data Set (UDS), including the UDS Global Composite 5 score (UDSGC5). RESULTS: Statistically significant correlations were found between the UDSGC5 and PVA-corrected measure of mean diffusivity (MDc, r = -0.35, p < 0.05) from DTI and the intracelluar volume fraction (ficvf, r = 0.37, p < 0.04) from NODDI. A sensitivity analysis showed that the relationship to MDc was driven by episodic memory, which is often affected early in AD, and language. CONCLUSION: This cross-sectional study suggests that multi-shell dMRI of the fornix that has been corrected for PVA is a potential biomarker for early cognitive domain changes in AD. A longitudinal study will be necessary to determine if the imaging measure can predict cognitive decline.

Microglial phagolysosome dysfunction and altered neural communication amplify phenotypic severity in Prader-Willi Syndrome with larger deletion.

Prader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder of genetic etiology, characterized by paternal deletion of genes located at chromosome 15 in 70% of cases. Two distinct genetic subtypes of PWS deletions are characterized, where type I (PWS T1) carries four extra haploinsufficient genes compared to type II (PWS T2). PWS T1 individuals display more pronounced physiological and cognitive abnormalities than PWS T2, yet the exact neuropathological mechanisms behind these differences remain unclear. Our study employed postmortem hypothalamic tissues from PWS T1 and T2 individuals, conducting transcriptomic analyses and cell-specific protein profiling in white matter, neurons, and glial cells to unravel the cellular and molecular basis of phenotypic severity in PWS sub-genotypes. In PWS T1, key pathways for cell structure, integrity, and neuronal communication are notably diminished, while glymphatic system activity is heightened compared to PWS T2. The microglial defect in PWS T1 appears to stem from gene haploinsufficiency, as global and myeloid-specific Cyfip1 haploinsufficiency in murine models demonstrated. Our findings emphasize microglial phagolysosome dysfunction and altered neural communication as crucial contributors to the severity of PWS T1's phenotype.

Development of an MR-Guided Focused Ultrasound (MRgFUS) Lesioning Approach for the Fornix in the Rat Brain.

OBJECTIVE: High-intensity magnetic resonance-guided focused ultrasound (MRgFUS) is a non-invasive therapy to lesion brain tissue, used clinically in patients and pre-clinically in several animal models. Challenges with focused ablation in rodent brains can include skull and near-field heating and accurately targeting small and deep brain structures. We overcame these challenges by creating a novel method consisting of a craniectomy skull preparation, a high-frequency transducer (3 MHz) with a small ultrasound focal spot, a transducer positioning system with an added manual adjustment of ∼0.1 mm targeting accuracy, and MR acoustic radiation force imaging for confirmation of focal spot placement. METHODS: The study consisted of two main parts. First, two skull preparation approaches were compared. A skull thinning approach (n = 7 lesions) was compared to a craniectomy approach (n = 22 lesions), which confirmed a craniectomy was necessary to decrease skull and near-field heating. Second, the two transducer positioning systems were compared with the fornix chosen as a subcortical ablation target. We evaluated the accuracy of targeting using histologic methods from a high-frequency transducer with a small ultrasound focal spot and MR acoustic radiation force imaging. RESULTS: Comparing a motorized adjustment system (∼1 mm precision, n = 17 lesions) to the motorized system with an added micromanipulator (∼0.1 mm precision, n = 14 lesions), we saw an increase in the accuracy of targeting the fornix by 133%. CONCLUSIONS: The described work allows for repeatable and accurate targeting of small and deep structures in the rodent brain, such as the fornix, enabling the investigation of neurological disorders in chronic disease models.